Service Bulletin No. 632 B

Identification of Connecting Rods with Non-Conforming Small End Bushings

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August 4, 2017


(1) Engines with a serial number listed in Table 1 of this Service Bulletin
(2) Engines that have been overhauled or repaired that could contain connecting rod assemblies or connecting rod bushings shipped from Lycoming during dates identified in Table 2 of this Service Bulletin


Within the next 10 hours of engine operation


Clarified MODELS AFFECTED; added NOTICE on page 1; clarified Steps 1.B and 4.B in “Required Action”; under the “Connecting Rod Bushing Press-Out Verification Procedure” - deleted Step 1 (reference to SB-630), added new Steps 7, 9, and 10 and new Figure 9 for better measuring procedure for indication of bushing movement, clarified the NOTICE after Step 11.A.(2) on page 5; added text to “use new seals and gaskets” in Steps 11.A.(4) and 11.B.(2) on pages 5 to 6; added IO-580 and AEIO-580 engine models to row for LW-12034 in the Top Overhaul Gasket Kit table on page 9.

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