SERVICE BULLETIN No. 3548

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SERVICE BULLETIN No. 3548 Piper Aircraft Corporation Lock Hoven, Pennsylvania, U.S.A. Modiflcation FAA Approved May 19, 1982 (Voids and supersedes Service Bulletin No. 141 dated October 4, 1955 .) ~ Voids and supersedes Service Letter No. 35! dated Decen;_ber 23, 1960 .) V01ds and supersedes Servtce Bullettn No; 3~4 dated Tune::> 1972.) Voids and supersedes Service Bullenn No. 354A dated April19, 1982 .) Subject: Fuel Selector Valve Lubrication s Reason for Revision: Revise Serial Numbers, announce replacement parts. Models Affected: Pil-18 Super Cub Senes PA- 20 Pacer Series PA-22 Tri-Pacer PA-24-180 Comanche PA-24-250 Comanche Serial Numbers Affected: 18-1 to 18-7909039 Inclusive 20-1 to 20-1121 Inclustve 22-1 to 22-9393 Inclusive 24-1 and Up. 24-1 to 24-"2174 Inclusive 24-2176 to 24-2298 Inclusive NOTE: This Bulletin applies to only those aircraft equipped with metal plug fuel selector valve with Part No. 11383-00, -02, -03, or -04. If original installation has been replaced with Plastic Plug Fuel Selector Valve with Piper Part Number 77413-02 refer to Piper Service Letter No. 944. Compliance Time: 1. Within the next ten (10) hours of operation from Effectivity Date, below, check fuel selector valve for ease of rotation. Repeat at 100 hour intervals. a. If selector is difficult to rotate, comply with provisions of InstrucLions on Page 2. b. If selector rotates easily, no further action is required at this time (See Compliance Time, section 2, below.). 2. Atrcraft with 400 hours or more time in operation; within the next one hundred (100) hours of operation or at one year's time from Effectivity Date, below, whichever occurs first. Comply with Instructions on Page 2. Aircraft with less than 400 hours time in operation; at 400 hours of operation or one year's time from Effectivity Date, below, whichever occurs first. Comply with Instructions on Page 2. (over) Service Bulletin No. 354B Page 2 of 6 Compliance Time: (continued) 2. continued The inspection/maintenance provisions of this Service Bulletin are to be repeated at every 400 hours of operation or annually, whichever occurs first. 'lllis inspection/maintenance procedure must also be conducted whenever the Fuel Selector Valve is difficult to operate. Purpose: The fuel selector valve installed in the above referenced aircraft models is a three position type valve Piper Part Numbers 11383-00, -02, -03 and -04 (depending on aircraft model application). An integral part of the above valves is the tapered plug which is the focal point of this Service Bulletin in the area of proper maintenance procedures . The tapered plug unless properly lubricated, is subject to binding or "freezing", caused by (1) fuel ccming in contact with the plug and gradually dissolving the film of lubricant, (2) presence of foreign material, and (3) hardened or congealed lubricants (usually caused by improper lubricant). The primary objective of this Service Bulletin is to insure that these valves are periodically and properly inspected and lubricated, in accordance with Instructions, below. Instructions: 1. With the valve removed from the aircraft, remove the valve cap and intenor parts (see attached sketch for an exploded view of valve components). 2. Inspect position washer inner perimeter surface for indications of extreme wear; should this be evident, replace position washer. (See Material Required, below.) 3. Check condition of plug and valve body for scored surfaces. The surfaces, if not badly scored, may be conditioned by lapping with a fine grinding compound. Clean away all compound after lapping. If plug will not seat properly or if scoring remains evtdent, replace valve with Valve Replacement Kit 764 295. 4. Check condition of valve stem in the area where the "0" ring seats. Should the stem be worn or damaged so that the "0" Ring will not seal, replace valve with Valve Replacement Kit 764 295. 5. With a lOx magnifying glass, inspect valve ports for cracks; if cracks are visible, replace valve with Valve Replacement Kit 764 295. NOTE: Valve Replacement Kit 764 295 contains Valve, Piper Part No. 77413·02. Refer to Piper Service Letter No. 944 if Part No. 77413-02 is installed. 6. Clean valve of all foreign matter, lubricate plug with a light film of MIL-G-6032 (Type I) grease, turn the plug several times in its seat and wipe off any excess, especially in the valve ports. Also, lubricate position washer with a light film of MIL-G-6032 (Type I) grease. Reassemble valve with a new "0" ring, Piper Part Number 752 822. Service Bulletin No. 354B Page 3 of 6 Instructions: (continued) 7. Rotate fuel selector to check for smooth operation and to insure proper seating in detent positions . 8. Before reinstalling valve, it may be checked by attaching an air hose and determining that it will withstand 50 PSI of air pressure without leaking. 9. After reinstallation of valve, check operation and check for fuel leaks. 10. Make appropriate logbook entry of compliance with this Service Release. Material Required: 1. MIL-G-6032 Grease, Plug Valve (Type I) which may be procured locally under the brand names specified on the Qualified Products List (of products qualified under military specification MIL-G- 6032) reproduced on pages 5 and 6. 2. One (1) each per aircraft Position Washer, Piper Part Number 756 645. 3. One (1) each per aircraft "0" Ring, Piper Part Number 752 822. 4. Only if required per Instruction 3, 4 or 5, Valve Replacement Kit 764 295. Availability of Parts: Your Piper Field Service Facility. Effectivity Date: This Service Bulletin in effective upon receipt. Summary: Please contact your Piper Field Service Facility to make arrangements for compliance with this Service Release, which is submitted tn the interest of helping you maintain your fuel system in proper operattng conditiOn. Service 13ullettn 1'-:o. 35413 Page 4 of o o~------ "0'' Ring o----washer @r-•,..----Spring