Component Maintenance Manual for External Design Wheels ...

3. Wheel Assembly Troubleshooting ..................................................................................... 104 SECTION 200 - ON-AIRCRAFT MAINTENANCE....................................................................... 201 1. General .............................................................................................................................. 201 2. Brake Assembly On-Aircraft Inspection and Maintenance ................................................ 201 A. Brake Inspection.......................................................................................................... 201 B. Corrective Maintenance of Brakes .............................................................................. 201 (1) Replacement of Metallic Brake Linings ................................................................ 202 (2) Replacement of Organic Brake Linings ................................................................ 204 (6) Lining Conditioning Procedures ........................................................................... 209 3. Wheel Assembly On-Aircraft Inspection and Maintenance................................................ 210 A. Nose and Tail Wheel Inspection .................................................................................. 210 B. Main Wheel Inspection ................................................................................................ 210 4. Tire On-Aircraft Inspection and Maintenance .................................................................... 210 SECTION 300 - OFF-AIRCRAFT MAINTENANCE ..................................................................... 301 1. General .............................................................................................................................. 301 2. Brake Assembly Off-Aircraft Maintenance ......................................................................... 301 A. Removal From Aircraft................................................................................................. 301 B. Brake Disassembly...................................................................................................... 302 (1) Disassembly Procedures ...................................................................................... 302 (2) Lining Removal ..................................................................................................... 305 (3) Anchor Bolt Removal ............................................................................................ 306 C. Inspection .................................................................................................................... 307 D. Brake Reassembly ...................................................................................................... 309 (1) Reassembly Procedures ...................................................................................... 309 (2) Installation of Pistons ........................................................................................... 310 (3) Lining Installation .................................................................................................. 310 (4) Further Reassembly of Brake Components ......................................................... 310 E. Storage ........................................................................................................................ 311 3. Wheel Assembly Off-Aircraft Maintenance ........................................................................ 311 A. Bearing Grease ........................................................................................................... 312 B. Removal From Aircraft................................................................................................. 312 (1) Removal of Main Wheel ....................................................................................... 312 (2) Removal of Nose Wheel ....................................................................................... 313 (3) Removal of Tail Wheel .......................................................................................... 314 Manual AWBCMM0001-28/USA Return to Table of Contents Table of Contents 1 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual 1 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE SUBJECT PAGE C. Wheel Disassembly..................................................................................................... 315 (1) Tire Removal ........................................................................................................ 315 (2) Bearing Cone Removal ........................................................................................ 316 (3) Inflation Valve Removal ........................................................................................ 317 (4) Bearing Cup Removal .......................................................................................... 317 D. Inspection .................................................................................................................... 318 E. Wheel Reassembly ..................................................................................................... 321 (1) Bearing Cup Installation ....................................................................................... 321 (2) Tire Mounting ........................................................................................................ 322 (3) Disc Installation .................................................................................................... 323 (a) Brake Disc Attached with Wheel Tie Bolts ...................................................... 323 (b) Brake Disc Not Attached with Wheel Tie Bolts ............................................... 324 (4) Inflation Valve Installation ..................................................................................... 325 (5) Bearing Installation ............................................................................................... 325 (6) Tire Inflation .......................................................................................................... 326 F. Storage ........................................................................................................................ 326 4. Brake and Wheel Refinishing ............................................................................................ 327 A. Degreasing .................................................................................................................. 327 B. Paint Removal ............................................................................................................. 328 C. Surface Pretreatment .................................................................................................. 329 D. Repainting ................................................................................................................... 330 5. Installation of Brake and Wheel Assemblies Onto Aircraft................................................. 332 A. Brake Installation ......................................................................................................... 332 B. Wheel Installation ........................................................................................................ 333 (1) Main Wheel .......................................................................................................... 333 (2) Nose Wheel .......................................................................................................... 334 (3) Tail Wheel ............................................................................................................. 335 APPENDIX A - WEAR LIMITS AND TORQUE VALUES ............................................................. A-1 A1. Brake Lining Wear Limits ............................................................................................... A-1 A2. Brake Disc Minimum Thickness ...................................................................................... A-2 A3. Back Plate Tie Bolt Torque ............................................................................................. A-4 A4. Wheel Assembly Torque Values ...................................................................................... A-8 A5. Tire Inflation Valve Stem Torque...................................................................................... A-11 APPENDIX B - SPECIAL TOOLS / LUBRICANTS / REPAIR MATERIALS................................. B-1 B1. Special Tools ................................................................................................................. B-1 B2. Lubricants For Elastomeric Compounds ......................................................................... B-1 B3. Lubricants ....................................................................................................................... B-1 B4. Surface Repair ................................................................................................................ B-2 B5. Primers and Paints .......................................................................................................... B-2 B6. Chemical Stripping Agents .............................................................................................. B-2 APPENDIX C - BRAKE ASSEMBLY / LINING CROSS-REFERENCE ....................................... C-1 C1. Brake Assembly / Lining Cross-Reference ..................................................................... C-1 Manual AWBCMM0001-28/USA Return to Table of Contents Table of Contents 2 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual 2 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE FIGURES PAGE 1 Typical External Wheel and Brake .........................................................................................7 2 Typical External Disc Brake....................................................................................................9 3 Typical Nose/Tail Wheel Assembly ....................................................................................... 11 4 Typical Main Wheel Assembly .............................................................................................. 12 201 Pin Installation, Metallic Lining ........................................................................................... 203 202 Rivet Installation, Organic Lining ........................................................................................ 206 203 Pressure Plate Straightening.............................................................................................. 207 204 Rivet/Pin Installation, Acceptance Criteria For Metallic and Organic Linings ..................... 207 205 Installation of 066-00504 Lining to Brake Shoe.................................................................. 208 301 External Piston Guide......................................................................................................... 303 302 Internal Piston Guide .......................................................................................................... 305 303 Anchor Bolt Removal.......................................................................................................... 306 304 Cylinder To Back Plate Surface Inspection ........................................................................ 307 305 Anchor Bolt Installation....................................................................................................... 309 306 Tire Removal ...................................................................................................................... 316 307 Bearing Cup Removal ........................................................................................................ 317 308 Bead Seat Inspection ......................................................................................................... 318 309 Disc Coning Limits.............................................................................................................. 320 310 Disc Inspection ................................................................................................................... 320 311 Bearing Cup Installation ..................................................................................................... 322 312 Wheel Tie Bolts .................................................................................................................. 324 313 Pack Bearing Cones........................................................................................................... 325 314 Typical Torque Plate (Cast), Painted Surfaces ................................................................... 330 315 Typical Brake Cylinder, Painted Surfaces .......................................................................... 331 316 Typical Wheel Half, Painted Surfaces ................................................................................ 331 A1 Minimum Lining Thickness ................................................................................................. A-1 A1-1 Disc Wear Measurement (Piper Aztec) .............................................................................. A-1 A2 Disc Thickness Measurement ............................................................................................ A-2 A3 Back Plate Tie Bolts ........................................................................................................... A-4 TABLES PAGE -- Units of Measure ....................................................................................................................5 101 Brake Assembly Troubleshooting ....................................................................................... 101 102 Wheel Assembly Troubleshooting ...................................................................................... 104 Manual AWBCMM0001-28/USA Return to Table of Contents List of Figures and Tables 3 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual 3 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE General There are a variety of publications available from Cleveland Wheels & Brakes to assist in the maintenance, overhaul or troubleshooting of Cleveland products. These documents are intended to supplement, not replace, the airframe manufacturer’s instructions when Cleveland products are used. The “Component Maintenance Manual” (CMM) is an excellent reference publication used by many installers and technicians. It has been generically written to address the common practices and procedures used to inspect, troubleshoot and overhaul most General Aviation external type wheels and brakes. The CMM is often used in conjunction with the Product Catalog which presents detailed illustrated parts breakdowns. The more complex internal type wheels and brakes generally have a manual expressly written for their overhaul and maintenance type activities. Manual Use Use of this manual requires reference to the Cleveland Wheels & Brakes Product Catalog. When referencing the Product Catalog, please note the term “cylinder assembly” or “caliper” is a reference to a brake assembly which includes the cylinder in addition to a back plate, pressure plate, brake linings, piston(s), and other components. The term “cylinder” is used to identify the housing for the piston(s), o-rings, and brake fluid. The cylinder is a component of the caliper. When referencing the Product Catalog, you may note terms “cylinder assembly” and “caliper” being used interchangeably. Manual Updates The manual publication number will reflect the latest issue in effect with a suffix “-X” (X being the latest issue), e.g. AWBCMM0001-8. The publication number will advance numerically with each update issued. Each page will reflect the latest issue in effect. Refer to the Revision Highlights Page in this publication for details of each update. Consult the Parker Hannifin website, www.parker.com, for current publications. For additional information regarding publications on CD-Rom, please contact the Cleveland Wheels & Brakes Technical Support Team. For technical assistance, contact the TECHNICAL SERVICES HOTLINE: clevelandwbhelp@parker.com 1-800-BRAKING (272-5464) Fax: 440-937-5409 NOTE: This manual, along with the Product Catalog, is also available as part of a Parker General Aviation Product Information CD ROM. Manual AWBCMM0001-28/USA Return to Table of Contents Introduction 4 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual 4 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Units of Measure The measurements used in this manual are presented in U.S. Standard Units with metric equivalents in parentheses after or below the U.S. units. Conversions and abbreviations are listed in the following table: U.S. Standard Unit U.S. Standard Abbreviation Corresponding Metric Unit Metric Abbreviation degrees Fahrenheit °F degrees Celsius °C foot pounds ft-lb Newton-meter N·m gallon gal liter l inch in. millimeter mm inch pounds in-lb Newton-meter N·m mile mi kilometer km miles per hour mph kilometers/hour km/hr ounce oz milliliter ml pounds per square inch psi kilopascals kPa Abbreviations Abbreviations used in this manual are listed and defined below. para .... paragraph P/N .... part number ref .... reference Manual AWBCMM0001-28/USA Return to Table of Contents Introduction 5 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual 5 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Two part numbering methods have been used by Cleveland over the years to identify products. The long form is an eight-digit (computer friendly) number and is used to identify detail and subassembly parts. The short form can contain both alpha and numeric characters. Past practices used the short form number on all of the products. Current practice is the use of the eight-digit format to identify all detail and subassembly components. Top assemblies are identified using the FAA TSO approval. These are usually short form numbers, but occasionally are long form, or neither form, depending on the era in which the approval was granted. To convert from the short form to the long form use the following method: 1. Examples of converting older short version part numbers to the current eight-digit format is shown below: Example: 65-144 becomes 065-14400 2. For numbers not ending in 00, replace the last two digits with a letter using the table below as a reference. Example: 65-144C becomes 065-14403 01=A 06=F 11=L 16=R 21=W 02=B 07=G 12=M 17=S 22=X 03=C 08=H 13=N 18=T 23=Y 04=D 09=J 14=P 19=U 24=Z 05=E 10=K 15=Q 20=V Letter I and O are deleted, so as not to be confused with the numbers 1 and 0. Manual AWBCMM0001-28/USA Return to Table of Contents Part Numbering System 6 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 1 - Typical External Wheel and Brake 1. Wheel and Brake Assemblies All wheel and brake combinations, Reference Figure 1, are matched components and qualified as such in accordance with Technical Standard Order (TSO) C26. Unauthorized substitution of wheel and brake components is a violation of the TSO of which the units are jointly qualified, and is prohibited. Manual AWBCMM0001-28/USA Return to Table of Contents Description and Operation 7 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE 2. Brake Assemblies The brake assembly and disc combination have been designed and qualification tested in accordance with Technical Standard Order (TSO) C26 and specific aircraft requirements to properly and safely decelerate the aircraft under various conditions. Unauthorized substitution of components can compromise brake effectiveness, is a violation of the qualification basis, and is prohibited. A. Brake Description The brake is an external caliper-type design. The cylinder (1), Ref. Figure 2, is a cast aluminum or magnesium housing. The pistons (7) are contained by the cylinder and form a pressure vessel for the brake fluid. Two anchor bolts are press fitted into the cylinder and are retained with nuts (12) and washers (13). The pressure plate (5) is held in position by the two anchor bolts. Back plate (4) is secured to the cylinder with bolts (2) and washers (3) on the opposite side of the brake disc. The back plate and pressure plate each hold brake linings (11). The cylinder is allowed to slide or float in torque plate (16) bushings. The torque plate is mounted to the landing gear axle. The caliper (cylinder assembly) is the assembly which includes the cylinder, pistons, back and pressure plates, linings, and other related components. Back plate to cylinder insulator shim (18) and piston to pressure plate insulator disc (17) are typically found on calipers that use the metallic based lining only. Specific illustrated parts breakdown for brake assemblies may be found in the product catalog. B. Brake Operation Hydraulic pressure, applied via the pilot’s and co-pilot’s master cylinders, enters the brake via lines connected to an inlet fitting on the caliper. The pressure then flows through the cylinder and forces the pistons outward against the pressure plate. The caliper should be free to slide on the torque plate assembly bushings allowing both pressure plate and back plate linings to contact the brake which will in turn contact the brake disc at precisely the same time. The braking action generates a torque which transmits a braking force converting the kinetic energy into heat which is absorbed by the brake disc and surrounding components. This braking force is transmitted to the wheel and into the tire, bringing the aircraft to a stop. Whenever a maximum energy Rejected Take Off (RTO) has occurred the intrinsic heat buildup can be quite severe and the components are to be inspected for airworthiness and overhauled in accordance with these procedures or procedures established by the airframe manufacturer. Releasing toe pedal pressure will allow the hydraulic pressure to decay in the brake caliper removing pressure from the disc. The wheel should be free to rotate with minimal drag. Some caliper designs incorporate a mechanism on the piston that will retract the piston and attached pressure plate lining away from the disc. These units are self-adjusting and retract to obtain approximately 0.02 to 0.04 inch of lining clearance to the disc. Manual AWBCMM0001-28/USA Return to Table of Contents Description and Operation 8 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 2 - Typical External Disc Brake Assembly 3. Wheel Assemblies All aircraft wheels are designed and qualification tested in accordance with TSO C26 for a particular tire type and size matching the aircraft requirements. Operating a wheel assembly with unapproved tires, improper inflation pressures or subjected to loads in excess of its design is a violation of the wheel certification basis and is prohibited. Description and operation of three different wheel assemblies is covered in the following text. The nose wheel assembly and the tail wheel assembly are sufficiently similar to consider together. The main wheel will be described separately. In each case, information is based on a typical wheel assembly. Specific Illustrated parts breakdown for wheel assemblies may be found in the Product Catalog. Manual AWBCMM0001-28/USA Return to Table of Contents Description and Operation 9 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE CAUTION: THE FELT GREASE SEALS ARE SHIPPED DRY. THEY MUST BE LUBRICATED TO PROVIDE PROTECTION AND LUBRICANT RETENTION FOR THE BEARINGS. IF THEY ARE NOT PROPERLY LUBRICATED THEN MOISTURE CAN SOAK PAST THE FELTS AND CONTACT THE BEARINGS WHICH CAN LEAD TO BEARING FAILURE. REFER TO PARAGRAPH 3.A AND 3.B BELOW. A. Nose and Tail Wheel Description Wheels are made from either aluminum castings, magnesium castings, or aluminum forgings. The wheel is of the divided type, incorporating inner wheel half (10) and outer wheel half (8), Ref. Figure 3, which are fastened together with tie bolts (7), washers (6), and nuts (5). An o-ring (9) fitted between the two wheel halves provides the air seal for wheels designed to operate with tubeless tires. The wheel rotates on two tapered roller bearings (4) which seat in bearing cups, shrink fitted into the hubs. Grease seals (3) provide protection and lubricant retention for the bearings. All new product shipped will have the bearings packed with the appropriate grease (refer to Section 300 Off-Aircraft Maintenance, paragraph 3.A. Bearing Grease). Felt grease seals are shipped dry. Remove the felt seals and lightly coat all surfaces of the felt with the wheel bearing grease and reinstall prior to wheel use. Hubcaps, when used, are secured to the outboard wheel half by a snap ring (1) or three attachment screws. Full wheel covers are fastened by three attachment screws. B. Main Wheel Description Wheels are made from either aluminum castings, magnesium castings, or aluminum forgings. The wheel is of the divided type, incorporating inner wheel half (10) and outer wheel half (8), Ref. Figure 4, which are fastened together with tie bolts (7), washers (6), and nuts (5). The brake disc (11) is attached to the wheel by the tie bolts. In a few designs, the brake disc bolts are threaded directly into inserts pressed into the back of the inboard wheel half. Wheels fall into two categories, tubeless and tube type. An o-ring (9) fitted between the two wheel halves provides the air seal for wheels designed to operate with tubeless tires. The wheel rotates on two tapered roller bearings (4) which seat in bearing cups in the hubs. Grease seals (3) provide protection and lubricant retention for the bearings. All new product shipped will have the bearings packed with the appropriate grease (refer to Section 300 Off-Aircraft Maintenance, paragraph 3.A. Bearing Grease). Felt grease seals are shipped dry. Remove the felt seals and lightly coat all surfaces of the felt with the wheel bearing grease and reinstall prior to wheel use. Hubcaps, when used, are secured to the outboard wheel half by a snap ring (1) or three attachment screws. Full wheel covers are fastened by three attachment screws. C. Wheel Operation The wheels, attached to the landing gear, support the tires and weight of the aircraft. The nose wheel provides a means of steering control, if so equipped. The main wheels transmit stopping forces from the brake to the ground. Manual AWBCMM0001-28/USA Return to Table of Contents Description and Operation 10 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 3 - Typical Nose/Tail Wheel Assembly Manual AWBCMM0001-28/USA Return to Table of Contents Description and Operation 11 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 4 - Typical Main Wheel Assembly Manual AWBCMM0001-28/USA Return to Table of Contents Description and Operation 12 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Component Maintenance Manual Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE 1. General This section provides information necessary to identify, diagnose, and correct potential problems which may occur with the wheel or brake assemblies. 2. Brake Assembly Troubleshooting Refer to the troubleshooting chart in Table 101 for assistance in diagnosing brake related difficulties. When a correction has been identified for a particular problem, refer to the appropriate reference in either the ON-AIRCRAFT or OFF-AIRCRAFT MAINTENANCE sections of this manual, or if available, refer to individual wheel and brake maintenance manual for the specific aircraft application. Table 101 Brake Assembly Troubleshooting TROUBLE PROBABLE CAUSE CORRECTION 1. Unable to obtain sufficient hydraulic brake pressure. Air in hydraulic system. Check for source, then bleed hydraulic system. Excessive toe pedal travel; spongy pedal. Vent in master cylinder reservoir clogged. Clean vent or overboard drain. Leak in system; brake, master cylinder, fittings, or lines. Locate leak and repair. Defective master cylinder. Replace or repair. Back plate bolts loose (not properly torqued), causing excessive brake deflection. Torque bolts to proper value. See Torque chart in Appendix A. Excess bolt torque has caused back plate to crush cylinder, evidenced by depressions around bolt holes. Replace cylinder and follow manufacturer’s recommended torque values. Defective brake line (ballooning). Replace. Improper adjustment of master cylinder rod length restricting the development of maximum stroke. Adjust length per the aircraft maintenance manual. Manual AWBCMM0001-28/USA Return to Table of Contents Troubleshooting 101 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 100 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Table 101 - Continued Brake Assembly Troubleshooting TROUBLE PROBABLE CAUSE CORRECTION 2. Brake drag. Piston cocked in cylinder, resulting in overheating brake and/or excessive lining wear. Remove and repair cylinder or piston, or replace brake. Foreign matter wedged in brakes. Locate and remove. Back pressure due to malfunction of master cylinder or parking valve. Bleed hydraulic system and/or repair/replace master cylinder or parking valve. Water or ice in hydraulic system. Flush and bleed hydraulic system (thaw ice first). Excessive bolt torque has caused back plate to crush cylinder, evidenced by depressions around bolt holes. Replace cylinder and follow manufacturer’s recommended torque value. Piston does not retract. Bleed system and/or remove piston. Inspect for damage. Warped pressure plate. Replace pressure plate or flatten to within 0.010 inch (0.254 mm). Rigid hydraulic line(s) prevents brake from floating freely. Flexible hydraulic lines are recommended. Check free cylinder movement. Position cylinder and re-tighten fitting. Corroded anchor bolts and/or torque plate bushings. Clean and lubricate or replace. Cocked anchor bolts and/or torque plate bushings. Replace. Bent/cracked torque plate. Replace. Warped brake disc - can be checked by laying a straightedge across disc face. Replace and use caution during operation to prevent excessive energy input into brake. Out of position/stuck lining. Repair/replace. Restriction in hydraulic line. Isolate and remove restriction. Lining not firmly seated flush against pressure/back plate. Debur rivet hole on surface adjacent to lining. Manual AWBCMM0001-28/USA Return to Table of Contents Troubleshooting 102 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 100 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Table 101 - Continued Brake Assembly Troubleshooting TROUBLE PROBABLE CAUSE CORRECTION 3. Rapid disc and lining wear. Dragging brakes. See Table 101, Trouble #2. Improper conditioning of brake linings. See lining conditioning procedures, ON-AIRCRAFT MAINTENANCE PARA 2.B. (2) Excessive rusting, scoring, or pitting of brake disc Clean or replace disc. Use factory chrome-plated disc where applicable. Excessive back plate deflection caused by bent bolts or over torquing bolts. Check and replace bolts. Check torque per Appendix A. Incorrect lining and/or disc. Replace with correct parts. 4. Brakes won’t hold. Contaminated lining. Replace lining. Improper conditioning of brake linings. See lining conditioning procedures, ON-AIRCRAFT MAINTENANCE para 2.B. (2). Lining worn below minimum wear limits. Replace lining. Refer to Appendix A. Discs worn below minimum wear limits. Replace discs. Refer to Appendix A. Insufficient hydraulic pressure. See Table 101, TROUBLE #1 Organic brake lining carburized (overheated). Replace lining. Pressure plate contacting torque plate assembly. Check for correct torque plate/wheel installation. New Lining installed with old disc, Lining not seated in wear track creating partial contact with disc. Replace excessively worn disc. Manual AWBCMM0001-28/USA Return to Table of Contents Troubleshooting 103 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 100 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE 3. Wheel Assembly Troubleshooting Refer to the troubleshooting chart in Table 102 for assistance in diagnosing wheel related difficulties. When a correction has been identified for a particular problem, refer to the appropriate reference in either the ON-AIRCRAFT or OFF-AIRCRAFT MAINTENANCE sections of this manual, or if available refer to the specific wheel and brake maintenance manual for that equipment. Table 102 Wheel Assembly Troubleshooting TROUBLE PROBABLE CAUSE CORRECTION 1. Cracked or distorted wheel or wheel half. CAUTION: DO NOT ATTEMPT TO WELD OR REPAIR CRACKS IN WHEEL HALVES. Hitting rocks or other hard objects during landing or takeoff. Inspect wheel using Zyglo to determine condition. Replace wheel or wheel half. Use of sharp objects to break tire bead. Replace wheel or wheel half. Landing with flat tire or abnormally hard landing. Replace wheel or wheel half. Landing in crabbing position in crosswind causing excessive side force. Replace wheel or wheel half. Normal fatigue failure when used beyond expected wheel life. Replace wheel or wheel half. 2. Damaged bearing cone. Misalignment of bearings. Replace bearing cone being sure it is properly seated in bearing bore. Axle nut improperly torqued. Replace and torque axle nut to aircraft manufacturer’s specifications. Foreign matter in bearing grease. Check grease seals for damage. Replace seals and be sure bearing grease is free from foreign matter. Lack of bearing grease. Replace bearings and repack with grease. 3. Worn or damaged grease seals. Normal wear or improper installation. Replace grease seals. Manual AWBCMM0001-28/USA Return to Table of Contents Troubleshooting 104 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 100 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE CAUTION: RUNWAY ANTI-ICING FLUIDS AND CERTAIN DISINFECTANTS USED TO PREVENT THE SPREAD OF HOOF AND MOUTH DISEASE HAVE BEEN FOUND TO HAVE ADVERSE EFFECTS ON THE AIRCRAFT WHEEL AND BRAKE SYSTEM COMPONENTS. A HIGHER DEGREE OF PREVENTATIVE MAINTENANCE IS REQUIRED IN THOSE AREAS USING SUCH AGENTS. 1. General This section covers maintenance which can be performed while the wheel and brake assemblies remain attached to the aircraft. 2. Brake Assembly On-Aircraft Inspection and Maintenance On-aircraft inspection and maintenance of brake assemblies is essentially limited to inspection of the assembly and replacement of the linings. A. Brake Inspection (1) Visually inspect the brakes for corrosion, cracks, or other visible damage. Check inlet fitting bosses and anchor bolt lugs for cracks. Check inlet flares on aircraft side of rigid hydraulic tubing for fatigue cracks. (2) Check back plate attachment bolts to ensure they are properly torqued and have not worked loose. Gaps between the back plate and cylinder would be evidence of this. (3) Check fit of brake cylinder anchor bolts in torque plate bushings for sloppiness. This can be accomplished by grasping the cylinder and moving it; slight movement is normal. Excessive movement is cause for removal and detailed inspection. (4) Linings should be visually checked for extreme chipping on the edges. Lining worn to a minimum thickness of 0.100 inch (2.54 mm) must be replaced. (Ref. Appendix A for more details.) (5) Visually check torque plate for corrosion, cracks, loose anchor bolt bushings, or other visible damage. Anchor bolt bushings must be flat against torque plate surface. (6) Check for any brake fluid leaks. Organic linings which have been contaminated with fluid should be replaced. B. Corrective Maintenance of Brakes On-aircraft corrective maintenance of the brake assembly involves replacement of the linings. This maintenance procedure may be accomplished without raising the aircraft or removing the main wheel. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 201 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (1) Replacement of Metallic Brake Linings The minimum wear thickness for replacement of metallic linings is 0.100 inch (2.54 mm). Ref. Appendix A, Figure A1. The metallic lining is a sintered metal composition and is attached by torque pins which fit into the back surface (steel carrier plate) of the lining. The holes for the pins are not visible on the lining surface unless the lining is worn beyond its wear limit. Ref. Figure 201. (a) Removal of Linings from Calipers WARNING: BLOCK WHEELS AND ENSURE THAT PARKING BRAKE IS IN OFF POSITION. 1 Remove back plate attaching bolts and washers, and remove back plates, shims, and insulators (if applicable). 2 Carefully slide brake caliper out of torque plate bushing. 3 Slide pressure plate assembly (lining carrier) off anchor bolts. (b) Inspection of Caliper and Torque Plate Assembly Inspect the caliper for corrosion, bent anchor bolts, cracks around bolts, cracks around anchor bolt lugs and inlet fittings, and other visible damage. Inspect the torque plate assemblies for corrosion around anchor bolt bushings and excessive wear in bushings. (c) Replacement of Metallic Linings 1 On models so equipped, remove center retention rivet, by drilling out with a 1/8- inch drill. 2 Pry off old lining using a screwdriver. 3 Clean pressure plate and back plate surfaces of dirt, grease, etc. before installing new linings. 4 Inspect pressure plate and back plates for excessive warping. Straighten pressure plate to less than 0.010 inch (0.254 mm) flatness, as shown in Figure 203. 5 Check lining attachment pins for mushroomed heads or other visible damage. Damaged attachment pins must be replaced by carefully drilling out the pins. a Install replacement pin in holes in pressure plate or back plate with tail of pin toward the counterbored side of part. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 202 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE b Hole locations in pressure plates / back plates should allow installation of lining after pin upset. c Place pins and pressure plate or back plate on a flat metal surface. d Using appropriate rivet tools, install pins on pressure plate or back plate. e Check to be sure pins are tight and movement free with no distortion of parts. f Refer to Figure 204 for rivet / pin installation acceptance criteria. 6 Apply a light film of spray adhesive to steel carrier plate of lining and install lining segment onto pins. Fit of counterbores of the lining segments with pins can be a clearance to press fit depending on lining segment part numbers. Check to ensure the steel carrier plate is tight against the pressure plates / back plates. Ref. Figure 201. NOTE: The adhesive is used to maintain position of lining until brake is assembled onto disc, and will be burned off in the first few stops. Lining will remain in place on assembly trapped between the brake disc and pressure / back plates. 7 On design so equipped, install the center retention rivet as shown in Figure 202. PIN BACK PLATE (SHOWN) OR PRESSURE PLATE (STEEL CARRIER PLATE- INTEGRALLY PART OF LINING) L I N I N G L I N I N G BACK PLATE PIN TO CBORE MISALIGNMENT LINING STEEL CARRIER PLATE NOT SEATED TO BACKPLATE OR PRESSURE PLATE PROPER LINING INSTALLATION IMPROPER LINING INSTALLATION Figure 201 - Pin Installation, Metallic Lining Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 203 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (d) Reassembly of Metallic Linings to Caliper 1 Carefully wipe dirt, grease, etc. from cylinder, pressure plate, and portions of piston extending beyond cylinder face, and push piston back into cylinder. 2 Lubricate the anchor bolts with a dry film lubricant (Appendix B, Section B3) specified for your climate environment: amphibious/extremely wet or non- amphibious. DO NOT USE GREASE OR OIL. These materials will attract dirt and enhance the wear of the anchor pins. 3 Slide pressure plate with new lining over anchor bolts and install brake caliper into torque plate. 4 Install back plate attachment bolts and washers in brake caliper. 5 Install insulator shims (typically used with metallic lining) and spacers as applicable. 6 Slide back plates between brake disc and wheel/tire and install back plate attachment bolts and washers into back plates. 7 Torque brake assembly back plate tie bolts to values listed in Appendix A. Two different types of back plate tie bolts are used. The patch lock bolt (nylon material embedded in threaded end) will require replacement after 6 to 8 installations or whenever the bolts can be run in past the locking feature by use of fingers only. Bolts with drilled heads require safety wire after torquing. 8 Actuate brake pedal prior to towing or taxiing. Check lining for proper alignment and engagement onto pins. Lining steel carrier plate should be seated on back plate or pressure plate. Ref. Figure 201 NOTE: Actuating the brake pedal will ensure pistons are extended prior to towing or taxiing. This will minimize running clearance for proper placement of linings. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 204 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (2) Replacement of Organic Brake Linings The organic brake lining is identified by its semi hard composition and rivets used to attach the lining to the pressure plate or back plate. The rivet holes are visible on the lining. Non asbestos, lead free lining material is also being used as a replacement for the old style organic lining and is removed and installed in the same manner as the organic lining. Ref. Figure 202. Appendix C provides a brake assembly / lining cross-reference information. (a) Removal of Linings from Calipers WARNING: BLOCK WHEELS AND ENSURE THAT PARKING BRAKE IS IN OFF POSITION. 1 Remove back plate attaching bolts and washers, and remove back plates, shims, and insulators (if applicable). 2 Carefully slide brake caliper out of torque plate bushing. 3 Slide pressure plate assembly (lining carrier) off anchor bolts. (b) Inspection of Caliper and Torque Plate Assembly Inspect the caliper for corrosion, bent anchor bolts, cracks around bolts, cracks around anchor bolt lugs and inlet fittings, and other visible damage. Inspect the torque plate assemblies for corrosion around anchor bolt bushings and excessive wear in bushings. (c) Replacement of Organic Linings 1 Old organic lining may be removed by using a small drift pin or carefully drilling out the rivets with a 1/8-inch diameter drill. Use care to prevent elongating the rivet holes. Deburr the surface adjacent to the lining to allow lining to set flush. 2 Clean pressure plate and back plate surfaces of dirt, grease, etc. before installing new linings. 3 Inspect pressure plate and back plate for excessive corrosion, visible damage, or excessive warping. Pressure plate should not be used if warped in excess of 0.010 inch (0.254 mm) flatness, by using draw flattening or straightening techniques. Ref. Figure 203. Excessive warping can result in brake drag, especially when new disc and linings are installed. 4 Align new factory authorized replacement lining segments on pressure plate/back plates and install rivets of corresponding part number, using appropriate riveting tools. 5 Check to be sure lining is tight and movement free with no distortion of parts. 6 With tubular rivets, splits may result from the clinching operation. Refer to rivet sketch, Figure 204, for acceptance criteria. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 205 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 202 - Rivet Installation, Organic Lining (d) Reassembly of Organic Linings to Caliper 1 Carefully wipe dirt, grease, etc. from cylinder, pressure plate, and portions of piston extending beyond cylinder face, and push piston back into cylinder. 2 Lubricate the anchor bolts with a dry film lubricant (Appendix B, Section B3) specified for your climate environment: amphibious/extremely wet or non-amphibious. DO NOT USE GREASE OR OIL. These materials will attract dirt and enhance the wear of the anchor pins. 3 Slide pressure plate with new lining over anchor bolts and install brake caliper into torque plate. 4 Install back plate attachment bolts and washers in brake caliper. 5 Install insulator shims (typically used with metallic lining) and spacers as applicable. 6 Slide back plates between brake disc and wheel/tire and install back plate attachment bolts and washers into back plates. 7 Torque brake assembly back plate tie bolts to values listed in Appendix A. Two different types of back plate tie bolts are used. The patch lock bolt (nylon material embedded in threaded end) will require replacement after 6 to 8 installations or whenever the bolts can be run in past the locking feature by use of fingers only. Bolts with drilled heads require safety wire after torquing. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 206 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (3) Pressure Plate Straightening Setup Technique (4) Rivet / Pin Installation Acceptance Criteria for Metallic and Organic Linings 1 The split shall not occur inside the crest of the clenched surface. 2 No more than two splits shall occur in a 90° area. 3 A total of no more than three splits shall be allowed. Figure 204 - Rivet / Pin Installation Acceptance Criteria For Metallic and Organic Linings Figure 203 - Pressure Plate Straightening Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 207 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (5) Installation of 066-00504 Lining to Brake Shoe a Using an 1/8 inch drill bit, drill out six rivets and remove the old lining from brake shoe. b Clean and deburr brake shoe as needed. c Place new lining on brake shoe, centered as closely as possible onto lining mount surface. Using a scribe, mark centerline location of 6 holes to be drilled in new lining. d Drill and counterbore lining as shown in Figure 205 (6 places). Mount new linings onto shoe with 6 rivets, P/N 105-00300; rivet head to seat to bottom of lining counterbore. Figure 205 - Installation of 066-00504 Lining to Brake Shoe Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 208 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (6) Lining Conditioning Procedures When new linings have been installed, it is important to condition them properly to obtain the service life designed into them. The metallic and organic linings are not conditioned in the same manner because they have different operating characteristics. Separate conditioning procedures are given for metallic and organic linings. ORGANIC LININGS METALLIC LININGS 1. Taxi aircraft for 1500 feet with engine at 1700 rpm applying brake pedal force as needed to develop a 5-10 mph taxi speed. 1. Perform two (2) consecutive full stop braking applications from 30 to 35 knots. Do not allow the brake discs to cool substantially between the stops. 2. Allow the brakes to cool for 10 to 15 minutes. 2. Allow the brakes to cool for 10-15 minutes. 3. Apply brakes and check for restraint at high static throttle. If brakes hold, conditioning is complete. 3. Apply brakes and check for restraint at high static throttle. If brakes hold, conditioning is complete. 4. If brakes cannot hold aircraft during static run up, allow brakes to completely cool, and repeat steps 1 through 3. 4. If brakes cannot hold aircraft during static run- up, allow brakes to completely cool, and repeat steps 1 through 3. CAUTION: DUE TO THE EFFICIENCY OF THESE BRAKES, EXTREMELY HARD BRAKING ON AIRCRAFT WITH TAIL WHEELS COULD RESULT IN LIFTING THE TAIL FROM THE GROUND. This conditioning procedure will wear off high spots and generate sufficient heat to create a thin layer of glazed material at the lining friction surface. Normal brake usage should generate enough heat to maintain the glaze throughout the life of the lining. Properly conditioned linings will provide many hours of maintenance free service. A visual inspection of the brake disc will indicate the lining condition. A smooth surface, one without grooves, indicates the linings are properly glazed. If the disc is rough (grooved), the linings must be reglazed. The conditioning procedure should be performed whenever the rough disc condition is observed. Light use, such as in taxiing, will cause the glaze to be worn rapidly. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 209 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE 3. Wheel Assembly On-Aircraft Inspection and Maintenance On-aircraft maintenance of wheel assemblies is limited to inspection of wheel assemblies. Inspections of the nose and trail wheels and of the main wheel are treated separately as follows. A. Nose and Tail Wheel Inspection Perform on-aircraft inspection as follows: (1) Visually inspect the wheels for corrosion, cracks, or other visible damage. (2) Check wheel nuts to be sure they are properly installed and have not worked loose. Bolt threads should be flush to 1.5 threads extending beyond the nut. B. Main Wheel Inspection Perform on-aircraft inspection as follows: (1) Visually inspect the wheels for corrosion, cracks, or other visible damage. (2) Check wheel nuts to be sure they are properly installed and have not worked loose. Bolt threads should be flush to 1-1/2 threads extending beyond the nut. Nuts should be on the side of wheel opposite the brake disc (outboard side of wheel), except in those cases where spline nuts and bolts are used to secure wheel halves. NOTE: Brake Disc cracks are not allowed unless covered by a PRM (Product Reference Memo) or SB (Service Bulletin) issued specifically for a brake disc. (3) Inspect the brake disc for rust, excessive grooves, large cracks, or other visible damage. Refer to Appendix A. 4. Tire On-Aircraft Inspection and Maintenance On-aircraft maintenance of tires is limited to inspection and air pressure maintenance. A. Tire Inspection (1) Visually inspect tires for cuts, flat spots, and tread or sidewall damage. (2) Check inflation pressure. Proper inflation will provide maximum tire and wheel life. (a) Pressure should be checked daily, when tires are cool. (b) Tubeless tires have an allowable 5% pressure loss in any 24-hour period. (3) Refer to tire manufacturer’s service and maintenance manuals for recommended servicing procedures. Manual AWBCMM0001-28/USA Return to Table of Contents On-Aircraft Maintenance 210 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 200 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE 1. General The following maintenance to brake assemblies and wheel assemblies is intended to be performed while these assemblies are off the aircraft. 2. Brake Assembly Off-Aircraft Maintenance This section provides complete repair and refinishing instructions for the brake assembly. When servicing the brake assembly, careful handling of the brake components will assure optimum service life and trouble free operation. CAUTION: A PRESSURE TEST [PARAGRAPH 2.D. (5)] IS REQUIRED WHENEVER THE FOLLOWING OCCURS: – ANY REPAIR TO THE CYLINDER PRESSURE CHAMBER OR PISTON. – ANY TIME A PISTON OR O-RING IS REMOVED WHICH CAN CAUSE DAMAGE TO THE O-RING; OR A NEW O-RING IS INSTALLED WHICH MAY UNKNOWINGLY BE DEFECTIVE. THE BRAKE CYLINDER AND TORQUE PLATE SHOULD BE PROPERLY MAINTAINED TO PROTECT THE PAINT AND SURFACE FINISHES; EXPOSED ALUMINUM OR MAGNESIUM IS SUSCEPTIBLE TO CORROSION. NICKS, SCRATCHES, AND OTHER DAMAGE CAUSED BY IMPROPER HANDLING OF BRAKE PARTS DURING MAINTENANCE INVITE CORROSION, WHICH IF UNATTENDED, COULD LEAD TO FATIGUE CRACKS AND BRAKE FAILURE. A. Removal From Aircraft NOTE: Wheel removal is not necessary unless brake torque plate is to be removed. The following procedure describes how to remove the brake assembly from the main wheel. WARNING: ENSURE PARKING BRAKE IS IN OFF POSITION AND WHEELS ARE BLOCKED. (1) Remove and cap hydraulic line attached to brake. Cap brake inlet fitting. (2) Remove back plate tie bolts and washers, and remove back plate. (3) Carefully slide brake cylinder out of torque plate. (4) If torque plate removal is required, remove wheel/tire per wheel removal instructions in paragraph 3. Wheel Assembly Off-Aircraft Maintenance. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 301 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE SAFETY WARNING : D E F L AT E T I R E I M M E D I AT E LY A F T E R J A C K I N G AIRCRAFT AND BEFORE AXLE NUT IS LOOSENED. FAILURE TO DEFLATE TIRE BEFORE WHEEL REMOVAL C O U L D R E S U LT I N S E V E R E P E R S O N A L I N J U RY. (5) Remove torque plate attachment bolts, nuts, and washers. Note the torque plate mounting rotational orientation for reinstallation. (6) Remove torque plate. B. Brake Disassembly (1) Disassembly Procedures The following disassembly procedures for the removed brake assembly also apply to dual caliper brakes. Disassembly should be performed only to the level required to effect necessary repairs. Refer to Figure 2, DESCRIPTION AND OPERATION section for a general illustration, or to the Product Catalog for the specific illustration of the unit being disassembled. CAUTION: DISASSEMBLE BRAKE ON A CLEAN, CUSHIONED, FLAT SURFACE, BEING CAREFUL NOT TO NICK, SCRATCH, OR GOUGE BRAKE PARTS. NOTE: Inspect parts in the dirty condition, as removed, for sources of leakage, damage, corrosion, and moisture in brake fluid. (a) Separate assembled cylinder (1) and torque plate (16). Brake assemblies that use metallic lining will also incorporate a thermal insulator shim (18) located between the back plate (4) and cylinder (1), and piston insulator (17), pressed into piston pocket, isolating piston (7), and pressure plate (5). (b) Remove back plate attachment bolts (2) and washers (3). Separate cylinder (1) and back plate (4). (c) Remove pressure plate (5) by sliding over anchor pins (14). (d) Remove inlet fitting. (e) On brakes so equipped, remove external retract mechanism from back of caliper. Note position of components for reassembly purposes. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 302 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 301 - External Piston Guide SAFETY WARNING : USE CAUTION IN BLOWING PISTONS OUT OF CYLINDER WITH AIR, AS PISTONS COULD FLY OUT AT HIGH VELOCITY. IT IS SUGGESTED THAT THE CYLINDER BE TURNED OVER SO THAT PISTONS FACE WORKING SURFACE. USE A RAG TO CUSHION PISTON CONTACT WITH SURFACE TO PREVENT PISTON DAMAGE. SAFETY GLASSES SHOULD BE WORN TO PROTECT EYES AND PREVENT DIRT OR BRAKE FLUID FROM ENTERING EYES. DEATH OR SERIOUS INJURY COULD OCCUR IF COMPRESSED AIR IS DIRECTED AGAINST THE SKIN. MAXIMUM PRESSURE SHALL NOT EXCEED 20 PSI (138 kPa). WHEN WORKING WITH COMPRESSED AIR ALWAYS USE CHIP GUARDS, EYE PROTECTION, AND OTHER PERSONAL PROTECTIVE EQUIPMENT. (f) Remove pistons (7) by injecting air into the ports (15 to 20 psi) [103 to 138 kPa] maximum pressure. NOTE: Some pistons are equipped with a friction spring (drag ring) on the piston tail. It is recommended that this ring not be removed unless it is damaged or corroded. Ref. Figure 301. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 303 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (g) Remove o-rings (8) from either pistons or cylinder. It is recommended that o-rings be replaced at reassembly. However, if necessary, o-rings may be reused if not damaged, cut, or deteriorated. CAUTION: CARE SHOULD BE USED IN HANDLING O-RINGS TO PREVENT DAMAGE. (h) If possible, it is always best to remove o-rings without the use of tools. This may be accomplished as follows: Securely holding piston in one hand, using opposite hand, form a “V” with thumb and index finger and push directly against o-ring to extrude it away from the piston groove on opposite side of piston. Push until outside diameter of the piston matches the natural radius on your hand between the index finger and thumb. Piston should now be held firmly in place with this hand. Grip extruded o-ring on opposite side and remove from piston. If this method is unsuccessful use Cleveland’s O-ring Extractor Kit, P/N 199-18, for o-ring removal. (i) A piston to pressure plate insulator disc is used on brake assemblies with metallic linings. Constant heat and pressure will compress the insulator over time. Replace the insulator when it is flush with the head of the piston. Drill 1/8” diameter hole directly into insulator approximately .10 inches deep, slightly off center, but not close to outside diameter of piston. Use small screwdriver working through the 1/8” diameter hole, lift and pry off insulator disc. (j) Remove bleeder fitting (9), rubber caps, and o-rings from cylinder. NOTE: Some designs have an internal piston guide (inside of the piston) attached to the cylinder by a bolt, washer, and Stat-O-Seal. It is recommended that this unit not be removed unless it is damaged or corroded. Ref. Figure 302. If Stat-O-Seal is removed, replace it. Do not reuse as it will not re-seal properly. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 304 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 302 - Internal Piston Guide (2) Lining Removal Removal of the linings is unique for both metallic and organic linings. The following text explains how to identify whether a lining is metallic or organic and gives step-by-step removal procedures. The minimum wear thickness on metallic and organic linings is 0.100 inch (2.54 mm) thickness. Ref. Appendix A, Figure A1. A brake assembly / lining cross-reference list is located in Appendix C. (a) Removal of Metallic Linings The metallic lining is a hard composition and is attached by pins which press fit into the back surface (steel carrier plate) of the lining. Ref. Figure 201. The holes for the pins are not visible on the lining surface unless the lining is worn beyond its wear limit. Remove as follows: NOTE: On some designs with a wide face lining, a rivet is also used for retention. 1 Pry lining off pressure plate/back plate with a thin screwdriver. 2 Damaged attachment pins may be removed by carefully drilling out the pin. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 305 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 303 - Anchor Bolt Removal (b) Removal of Organic Linings The organic brake lining is identified by its semi hard composition and rivets used to attach the lining to the pressure plate. The rivet holes are visible on the lining. Remove as follows: 1 Being careful not to enlarge holes in pressure plate/back plate, drill out rivets attaching lining with a 1/8-inch diameter drill. 2 Separate lining from pressure plate/back plate. (3) Anchor Bolt Removal NOTE: The anchor bolt is a press fit into the cylinder body and should only be removed if any of the following conditions are observed. • Scratches, nicks, pitting, corrosion, or evidence of overheating • Spinning when turned by hand • Movement when force is applied by hand • Elongated brake cylinder bore or evidence of movement in bore • A gap between the anchor bolt and cylinder housing (inspected visually or under magnification) NOTE: Please be aware of potential degradation of the press fit with repeated removals and replacements of the anchor bolts. (a) Remove anchor bolt attachment nuts (12) and washers (13). The anchor bolts should be removed by using an arbor press. Ref. Figure 303. (b) Place on a clean, flat surface to prevent damage and nicks to soft cylinder material. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 306 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 304 - Cylinder To Back Plate Surface Inspection C. Inspection NOTE: Parts of the inspection procedure require removal of paint. Refer to Section 4 for information concerning paint removal and refinishing of these parts. (1) Visually inspect cylinder for cracks, nicks, corrosion, or other damage. Cracks in the lug area around the anchor bolts or the port bosses are cause for replacement of the cylinder. Check for dimpled areas around back plate bolt holes. Maximum allowable depression is 0.005 inch (0.127 mm). Ref. Figure 304. (2) Inspect the fitting ports and piston bores for contamination. Light scratches or nicks in the piston bores, pilot bores, or on the chamfered surfaces within these bores may be hand polished with 600 grit emery. Power tools are not recommended as they may remove excessive amounts of material. Thoroughly clean part. NOTE: Heavy scratches, nicks and burrs in the pilot bore area can prevent the pistons from properly retracting, resulting in brake drag. (3) Replace o-rings with o-rings of corresponding part numbers. If necessary, o-rings may be reused in the same position from which they were removed if not damaged. Inspect o-rings for cuts, nicks, distortion, or excessive wear. Check to be sure o-ring has not become brittle. Refer to o-ring removal procedure in paragraph 2B (1)(h). Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 307 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA Section 300 External Design Wheels & Brakes Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (4) Inspect pistons for nicks or burrs. Check the piston tail for damage, and replace piston if damaged beyond repair. Remove nicks or burrs by hand polishing with 600 grit emery paper. Thoroughly clean part. (5) Inspect brake lining for edge chipping and surface deterioration. Normal use will result in some edge chipping. A maximum of 10 percent surface loss is acceptable. Minor accumulation of metal chips in lining is normal and not detrimental. Elongated rivet or pin holes is cause for replacement. Smearing of lining material on the brake disc which exceeds 30 percent of the surface is cause for replacement. NOTE: Any fluid contamination of organic brake lining is cause for replacement. (6) Inspect back plates and pressure plate for cracks, nicks, rust, warping, stripped threads, elongated holes, or other damage. Small nicks and light corrosion may be hand finished using emery of 600 grit sandpaper. Any area from which the protective coating is removed should be thoroughly cleaned and treated per instructions in Chapter 4 of this section. NOTE: Slightly warped pressure plates can be cold straightened, Ref. Figure 203. When laid on a flat surface, flatness should be within 0.010 inch (0.254 mm). Warped pressure plates can cause brake drag. (7) Inspect anchor bolt bushings in torque plate for internal corrosion or contamination. If present, clean with emery and apply a light coat of dry film lubricant (Appendix B, Section B3 for your climate environment). DO NOT USE GREASE OR OIL. Exercise care in removing corrosion from torque plate bushings to prevent material removal. NOTE: Cast torque plates have bushings press fit into the casting. The unit must be replaced as an assembly. Individual components are not available. (8) Check for steps in bushing holes, which indicate severe cocking of the cylinder anchor bolts in the torque plate. Bushing damage is cause for torque plate replacement. NOTE: Bushings installed in cast torque plates must have the lip of the bushing seated flat against the machined torque plate surface. (9) Check the anchor bolt bushings and mounting bolt hole areas for elongation or cracks. Badly elongated holes or cracked torque plates should be replaced with a new torque plate of corresponding part number. Minor corrosion on the torque plates should be removed with 600 grit emery. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 308 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE Figure 305 - Anchor Bolt Installation (10) Inspect bolts for cracks, bending, thread damage, or excessive corrosion. Bolts with evidence of any of these should be replaced with bolts of corresponding part numbers, as specified in the Cleveland parts list or catalog. Two different types of back plate tie bolts are used. The patch lock bolt (nylon material embedded in threaded end) will require replacement after 6 to 8 installations or whenever the bolts can be run in past the locking feature by use of fingers only. Bolts with drilled heads require safety wire after torquing. D. Brake Reassembly CAUTION: ASSEMBLE BRAKE ON A CLEAN FLAT SURFACE, BEING CAREFUL NOT TO NICK, SCRATCH, OR DAMAGE PROTECTIVE FINISH OF BRAKE PARTS. (1) Reassembly Procedures (a) Thoroughly clean parts before assembling. (b) If anchor bolts were removed, the following items shall be completed prior to installation. • Remove any surface corrosion from the anchor bolt hole diameter with a fine emery cloth or a scotch brite pad. If corrosion has caused pitting, the brake cylinder should be replaced. • Measure in any direction the anchor bolt hole diameter. The anchor bolt hole diameter shall not be larger than the diameter of the anchor bolt (line to line press fit is the minimum criteria). 1 Install anchor bolts using an arbor press and a holding fixture. Refer to Figure 305. Ensure that bolt is perpendicular to the cylinder and parallel to one another. 2 The press fit should be felt immediately when attempting to install the new bolt. 3 Install washers and nuts. Dry torque nuts to 90 inch-pounds (7.9 Nm). The torque to overcome the locking feature of the nut must be added to the above torque level to obtain the true torque. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 309 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (2) Installation of Pistons Installation of pistons with an internal guide is the same as for other pistons. Care must be taken to ensure that no damage to parts occurs during installation. If considerable effort is required, remove piston and inspect bore and pilot bore area for damage. If bore is damaged, check the corresponding area of piston for damage. (a) Place piston in bore and rotate to seat friction spring (if applicable), and ensure that piston and o-ring are in proper alignment. Press piston into bore by hand. Tap the piston squarely with a wooden or plastic mallet (if required) while rotating piston. (3) Lining Installation Refer to ON-AIRCRAFT MAINTENANCE Section 200 for detailed lining instructions. (4) Further Reassembly of Brake Components The remaining components of the dissembled brake unit shall be reassembled as follows: (a) Install inlet fitting, bleeder fitting, rubber caps, and O-rings, if applicable. A majority of the inlet fittings used on Cleveland brakes are pipe threads. Care should be exercised to prevent over tightening which could result in cracking of the cylinder casting. Install pipe thread fittings as follows. CAUTION: NEVER BACK OFF (LOOSEN) PIPE THREADED FITTINGS TO ACHIEVE ALIGNMENT. 1 Inspect and clean each fitting to remove any oil or surface contamination prior to assembly. CAUTION: AVOID COATING THE FIRST THREAD TO AVOID SYSTEM CONTAMINATION. 2 Apply a light coat of a thread lubricant (Lubon #404) to the threads of the fitting. 3 Screw the fitting into the port to the finger tight position. 4 Wrench tighten the fitting 1 to 1-1/2 turns from finger tight. Fittings that require a specific orientation to receive the incoming tube or hose assembly may be adjusted from 1 to 2 turns, beyond finger tight to achieve the desired location. Straight thread inlet fittings and bleeder adapter fittings with o-rings are to be torqued 65-70 in-lb. Bleeder seats are to be tightened snug to preclude leakage. NOTE: Cap fittings if brake is not being immediately installed on the aircraft. (b) Install pressure plate lining facing away from pistons by sliding over anchor bolts. Pressure plate should slide freely over anchor bolts. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 310 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (c) Install back plates with attachment bolts and washers. Install metal or insulating shim, if applicable. Do not tighten bolts if brake is to be installed on aircraft or put into storage. Insulating (fiber) shims are used on brakes with metallic linings. (d) A dry film lubricant (Appendix B, Section B3 for your climate environment) should be applied to anchor bolts and torque plate bushings to assist sliding motion. Exercise care to ensure that linings do not become contaminated with fluid or lubricant. For best service life, cylinders must slide freely in torque plate. (e) Install cylinder assembly in torque plate by sliding anchor bolts into bushings. (5) After installation on the aircraft, pressure test the brake assembly at 600 psi and check for leakage. E. Storage Brake assemblies which are not to be immediately installed on the aircraft must be properly stored. Acceptable storage conditions are listed below. CAUTION: BRAKES STORED IN CARDBOARD BOXES, WHICH HAVE BECOME WET OR HAVE BEEN EXPOSED TO HIGH HUMIDITY, CAN BECOME CORRODED. (1) The length of time that a brake assembly can be stored is governed by the storage life of its rubber components. Basically, rubber components are considered to have a storage life of up to ten years from the date of cure. The storage life may be shortened by exposure to sunlight, extreme temperatures, humidity, ozone, contamination of fluids, severe operating conditions, etc. (2) Normal storage environmental temperatures of 50° to 77°F (10° to 25°C) are desired. If this temperature range cannot be maintained, temperatures as high as 125°F (51.7°C) and as low as -20°F (-28.9°C) can be tolerated for shorter periods. Total time above 100°F (37.8°C) shall not exceed three months. 3. Wheel Assembly Off-Aircraft Maintenance This section covers the removal, disassembly, inspection, reassembly, and installation of the main, nose, and tail wheel assemblies. When conducting wheel maintenance, observe the following general cautions: • Careful handling of the wheel components will assure a long service life and trouble free operation. • Strictly observe the tire deflation and inflation procedures, and the torque values specified. Wheel nut torque values are shown on the nameplate or on the outboard wheel half. Do not overtighten any bolt, nut, or fitting. Do not employ impact or power wrenches to remove or tighten any threaded parts. • Handle the wheel bearing cones with extreme care. Many bearing failures can be traced to dropping or mishandling the cones during maintenance. Bearing cups and cones should be used as a matched set to provide maximum service life. Do not drive bearing cones onto the aircraft axle, and never overtighten the axle nut. For more information, refer to Timken Bearing Company’s catalog, “How to Recognize and Prevent Tapered Roller Bearing Damage.” Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 311 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE • The wheel halves should be properly maintained to protect the paint and surface finishes; exposed aluminum/magnesium is susceptible to corrosion. Nicks, scratches, and other damage caused by improper handling of the wheel halves during maintenance invite corrosion which, if unattended, could lead eventually to fatigue cracks and wheel failure. A. Bearing Grease CAUTION: DO NOT MIX AVIATION WHEEL BEARING GREASES WITH EACH OTHER. IF USING OTHER APPROVED GREASE, COMPLETE REMOVAL OF CONTAINED GREASE AND BEARING CLEANING IS REQUIRED. REPLACEMENT OF PREVIOUSLY LUBRICATED FELT GREASE SEALS IS ALSO REQUIRED. CAUTION: THE FOLLOWING GREASE CHANGE DOES NOT APPLY TO AMPHIBIOUS APPLICATIONS NOTED IN TABLE A4. Beginning March, 2007 all active wheel assemblies listed in Table A4, except those noted for amphibious application, will be shipped from the Cleveland Wheels & Brakes facility with the bearings packed with Mobil Aviation Grease SHC 100, the approved preferred grease for all Parker Hannifin wheel assemblies. NOTE: If your non-amphibious wheel assembly was shipped prior to March 2007 it may contain other approved bearing grease. To change to the Mobil Aviation Grease SHC 100, you must completely remove the contained grease and clean the bearings. You must also replace any felt grease seals which were previously lubricated with other approved grease. Refer to paragraph 3.E. (5) (a) for grease packing instructions. B. Removal From Aircraft Separate removal procedures are given for the main, nose, and tail wheels. (1) Removal of Main Wheel SAFETY WARNING : ENSURE AIRCRAFT IS SECURE AND STABLE BEFORE BEGINNING ANY WORK. WORKING UNDER AN IMPROPERLY STABILIZED AIRCRAFT COULD CAUSE INJURY OR DEATH. NOTE: Brake back plates must be removed for wheel removal. Refer to paragraph 2.A of this section. Hydraulic line need not be disconnected for wheel removal. (a) Remove wheel pants/fairings if aircraft is so equipped. (b) Properly raise the aircraft off the ground following the aircraft manufacturer’s instructions. (c) Remove hubcap/wheel cover, if applicable. SAFETY WARNING : DEFLATE TIRE IMMEDIATELY AFTER JACKING AIRCRAFT AND BEFORE AXLE NUT IS LOOSENED. FAILURE TO DEFLATE TIRE BEFORE WHEEL REMOVAL COULD RESULT IN SEVERE PERSONAL INJURY. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 312 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (d) Remove air from tire by depressing the valve stem plunger until air can no longer be heard escaping from the tire. SAFETY WARNING : DO NOT ATTEMPT TO REMOVE VALVE CORE UNTIL TIRE HAS BEEN COMPLETELY DEFLATED. VALVE CORES WILL BE EJECTED AT HIGH VELOCITIES IF UNSCREWED BEFORE AIR PRESSURE HAS BEEN RELEASED. (e) Remove valve core. (f) Remove cotter pin from axle and remove axle nut. (g) Rock wheel/tire slightly to unseat the outboard bearing. (h) Carefully remove and store the bearing. Label the bearing for reinstallation into position from which it was removed. (i) Remove wheel/tire. (j) Carefully remove and store inboard bearing. (2) Removal of Nose Wheel SAFETY WARNING : ENSURE AIRCRAFT IS SECURE AND STABLE BEFORE BEGINNING ANY WORK. WORKING UNDER AN IMPROPERLY STABILIZED AIRCRAFT COULD CAUSE INJURY OR DEATH. (a) Remove wheel pants/fairings if aircraft is so equipped. (b) Properly raise the aircraft off the ground following the aircraft manufacturer’s instructions. SAFETY WARNING : DEFLATE TIRE IMMEDIATELY AFTER JACKING AIRCRAFT AND BEFORE AXLE NUT IS LOOSENED. FAILURE TO DEFLATE TIRE BEFORE WHEEL REMOVAL COULD RESULT IN SEVERE PERSONAL INJURY. (c) Remove air from tire by depressing the valve stem plunger until air can no longer be heard escaping from the tire. SAFETY WARNING : DO NOT ATTEMPT TO REMOVE VALVE CORE UNTIL TIRE HAS BEEN COMPLETELY DEFLATED. VALVE CORES WILL BE EJECTED AT HIGH VELOCITIES IF UNSCREWED BEFORE AIR PRESSURE HAS BEEN RELEASED. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 313 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (d) Remove valve core. (e) Support wheel/tire and remove axle attachment bolts, nuts, and washers. In some cases, the nose wheel will be attached with an axle nut, similar to the main gear, which must be removed. (f) Remove wheel/tire, axle spacers, and shims. (g) Separate wheel/tire from axle, axle spacers, and shims. Carefully remove and store bearings. Label bearings for reinstallation into positions from which removed. (3) Removal of Tail Wheel SAFETY WARNING : ENSURE AIRCRAFT IS SECURE AND STABLE BEFORE BEGINNING ANY WORK. WORKING UNDER AN IMPROPERLY STABILIZED AIRCRAFT COULD CAUSE INJURY OR DEATH. (a) Properly raise the aircraft off the ground following the aircraft manufacturer’s instructions. SAFETY WARNING : DEFLATE TIRE IMMEDIATELY AFTER JACKING AIRCRAFT AND BEFORE AXLE NUT IS LOOSENED. FAILURE TO DEFLATE TIRE BEFORE WHEEL REMOVAL COULD RESULT IN SEVERE PERSONAL INJURY. (b) Remove air from tire by depressing the valve stem plunger until air can no longer be heard escaping from the tire. SAFETY WARNING : DO NOT ATTEMPT TO REMOVE VALVE CORE UNTIL TIRE HAS BEEN COMPLETELY DEFLATED. VALVE CORES WILL BE EJECTED AT HIGH VELOCITIES IF UNSCREWED BEFORE AIR PRESSURE HAS BEEN RELEASED. (c) Remove valve core. (d) Support wheel/tire and remove axle attachment bolts, nuts, and washers. (e) Remove wheel/tire, axle spacers, and shims. (f) Carefully remove and store bearings. Label bearings for reinstallation into positions from which removed. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 314 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE C. Wheel Disassembly The step-by-step disassembly procedure given below is common to the main, nose, and tail wheels. Disassembly should be performed only to the level required to effect necessary repairs. When doing any wheel maintenance, the technician shall first refer to the aircraft manufacturer’s maintenance manual for guidance. In the absence of detailed information from the aircraft manufacturer the technician may use the information in this publication by referring to Figure 3 or 4, Typical Wheel Assemblies, or to the Product Catalog for the specific unit being disassembled. Cleveland products of identical part number are used on a variety of different aircraft. The combined effects of negligent service, environmental conditions and the application itself may affect the service life of the product. Therefore, a very thorough inspection of the wheel and its components is recommended whenever the tire is changed or whenever the technician determines that it is warranted. Organizations that routinely perform their own maintenance may want to use their experiential observations to develop their own unique inspection procedures. Some organizations will perform the more thorough dye penetrant inspection after a predetermined number of tire changes with newly introduced wheel assemblies typically permitting the largest number of tire changes. The tire change to dye penetrant inspection interval will be progressively reduced as the time in service of the product increases. This type of program will eventually result in a more thorough dye penetrant detailed inspection at each tire change. SAFETY WARNING : DO NOT ATTEMPT TO DISASSEMBLE WHEEL UNTIL TIRE HAS BEEN COMPLETELY DEFLATED. SERIOUS INJURY TO PERSONNEL OR EQUIPMENT DAMAGE CAN RESULT IF THESE PRECAUTIONARY MEASURES ARE IGNORED. DO NOT ATTEMPT TO REMOVE VALVE CORE UNTIL TIRE HAS BEEN COMPLETELY DEFLATED. VALVE CORES WILL BE EJECTED AT HIGH VELOCITIES IF UNSCREWED BEFORE AIR PRESSURE HAS BEEN RELEASED. CAUTION: DISASSEMBLE WHEEL ON A CLEAN FLAT SURFACE, BEING CAREFUL NOT TO NICK, SCRATCH, OR GOUGE WHEEL HALVES. (1) Tire Removal (a) Remove valve cap and deflate tire completely. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 315 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE CAUTION: DO NOT PRY BETWEEN WHEEL FLANGE AND TIRE BEADS, AS THIS COULD CAUSE DAMAGE TO WHEEL AND TIRE. (b) Separate tire beads from wheel halves, using a bead breaker or by applying pressure in even increments around the entire sidewall of the tire as close to the tire beads as possible. Suggestion: Fabricate two each rings from a substantially thick piece of plywood. The inside diameter should be slightly larger than the wheel rim outside diameter. Sandwich the wheel/tire between the two rings and apply pressure to the top ring. The tube well area of the wheel is tapered and once the bead is broken the tire should slide progressively easier. Ref. Figure 306. (c) Remove nuts (5), washers (6), and bolts (7) holding wheel halves together. If brake disc bolts are separate from wheel tie bolts, remove them and separate brake disc (11) from wheel. (d) Separate inner wheel half (10), outer wheel half (8), and brake disc (11), and remove tire. Mark wheel halves to note relationship to each other for reassembly. (2) Bearing Cone Removal Remove hubcap/wheel cover, grease seals, and bearing cones. Use caution in handling bearing cones to prevent damage or contamination. CAUTION: USE CARE IN REMOVING OUTBOARD WHEEL HALF TO PREVENT DAMAGE TO INFLATION VALVE STEM. Figure 306 - Tire Removal Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 316 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (3) Inflation Valve Removal Remove o-ring (9) and inflation valve if wheel is designed for use with a tubeless tire. Mark o-ring with respect to wheel half for reassembly. Retaining o-ring position will aid in minimizing leakage at reassembly. It is recommended that the o-ring be replaced at reassembly. (4) Bearing Cup Removal The bearing cup is a shrink fit into the wheel half and should not be removed, unless replacement is necessary due to scratches, nicks, pitting, corrosion, or evidence of overheating. WARNING: USE PROTECTIVE GLOVES WHEN HANDLING HEATED PARTS. (a) If replacement is necessary, place wheel half in an oven not exceeding 212°F (100°C) for 15 minutes. (b) Remove wheel half from heat source and immediately remove bearing cup. If bearing cup does not fall out, tap it evenly with a fiber drift pin or use a suitable arbor press. Figure 307 - Bearing Cup Removal Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 317 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE D. Inspection (1) Visually inspect wheel halves for cracks, nicks, corrosion, or other damage. Any cracks in the wheel half are cause for replacement of wheel half. The tire bead seat area of a wheel (Fig 308) is typically an area of stress concentration and possibly subjected to trauma from tire beads and tools used to remove tires. These combined effects warrant that this area receive special attention when inspecting for defects. All defect indications must be thoroughly investigated to determine part airworthiness. Dye penetrant inspection and visual examination is an effective method to evaluate a defect indication. To facilitate the inspection process it is recommended that the paint be stripped in the area being evaluated. The use of alternate inspection methods such as eddy current can also be very effective when performed by an experienced NDT Technician. Cleveland has not developed the acceptance standards or tooling for eddy current inspection techniques. Maintenance facilities that want to use this method will have to locally develop tooling and acceptance standards that adequately identify defects. Replace any cracked or excessively corroded parts. Small nicks, scratches, or pits may be blended out and polished with fine sandpaper. Treat and repaint per paragraph 4. Brake and Wheel Refinishing. Figure 308 - Bead Seat Inspection Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 318 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (2) Inspect wheel bearing grease for contamination and solidification at each periodic inspection. Repack bearings with fresh grease – Refer to paragraph 3.A. Bearing Grease. NOTE: Repack wheel bearings per aircraft OEM requirements, at tire change or annual inspection (12 months), whichever comes first. If aircraft wheel uses felt seals, do not exceed 500 wheel miles (804.5 km) or annual inspection (12 months), whichever comes first between repacking intervals. (3) Inspect wheel half bearing cup bore for burrs, primer residue, or foreign matter. Make sure surface is clean. (4) Inspect snap rings and grease seals for distortion or wear. Replace grease seal felts if they are hard or contaminated. Lightly coat all surfaces of the new felt with the wheel bearing grease (refer to paragraph 3.A. Bearing Grease). Molded rubber grease seals should be replaced if cracked, dried out or distorted. (5) Wheel tie bolts by nature of their application are subjected to fatigue type loads. It is best to replace these fasteners at overhaul. If bolts are to be reused they must be inspected for cracks, bending, thread damage, or excessive corrosion. Bolts with evidence of any of these should be replaced with bolts of corresponding part numbers, as specified in the Cleveland Parts List or Catalog. Magnetic particle inspection is the recommended procedure for bolt inspection. Alternate nondestructive inspection techniques, such as ultrasonic inspection, can demonstrate determination of non-airworthy ferromagnetic products consistent with the fluorescent magnetic particle methods. Cleveland typically uses AN, MS, and NAS bolts which, as part of the procurement specification, employ the fluorescent magnetic particle inspection as one of the recognized standards in determining acceptance of product. Therefore, the acceptance standards and methodologies for the ultrasonic inspection techniques have not been specifically developed at Cleveland. Use of the ultrasonic method or any other inspection techniques is the responsibility of the agency determining airworthiness of the product. NOTE: Inspect self-locking nuts for damage. If nut can be turned onto bolt by hand, past the nut’s self-locking section, it should be replaced with nuts of corresponding part numbers. (6) Replace o-rings with o-rings of corresponding part numbers. If necessary, o-rings may be reused. Inspect o-rings for cuts, nicks, distortion, or excessive wear. Check to be sure o-ring has not become brittle or hard. NOTE: Brake disc cracks are not allowed unless covered by a PRM (Product Reference Memo) or SB (Service Bulletin) issued specifically for a brake disc. (7) Inspect brake disc for cracks, excessive wear, or scoring, mounting hole elongation, corrosion, and warpage. Remove corrosion and blend out small nicks using fine (400 grit) sandpaper. Replace brake disc if worn below wear limits detailed in Appendix A. Coning of disc in excess of 0.015 inch (0.381 mm) is cause for replacement. Ref. Figure 309. Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 319 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY REVISION BEFORE USE (8) Welded brake discs will have a slight gap on the side opposite the weld at the cup interface. This is normal. Ref. Figure 310. (9) Heat created during braking promotes the development of corrosion and pitting at the flange to cup area. Annually, or on condition, sandblast these areas or use a wire wheel to remove corrosion and pitting. Treat affected areas with zinc chromate primer and a coat of heat resistant spray paint. Heat resistant paints may be locally procured from auto parts supply. NOTE: Corrosion, if left unattended will result in decreased service life of the part. Figure 309 - Disc Coning Limits Figure 310 - Disc Inspection Manual AWBCMM0001-28/USA Return to Table of Contents Off-Aircraft Maintenance 320 Parker Hannifin Corporation Aircraft Wheel & Brake Division Avon, Ohio, USA External Design Wheels & Brakes Section 300 Released: 5/6/2022 Delivered from Parker Vault - VERIFY R