This procedure covers the replacement of the Single Cylinder Air
Compressor Rear Seal and Adapter Kit, Cummins kit part number
4089222. The repair kit includes an adapter, O-ring, gasket, and two flat
Remove two bolts (1, Figure I-3) securing the back cover (2).
Remove and discard cover gasket (3).
Remove two flat head screws (4), if installed. Then remove and discard the metal pump
Remove and discard O-ring seal (6).
Lube new O-ring seal (6, Figure I-3) with clean oil, MIL-L-2104. Then insert the seal into
the fillet pocket formed by the corner of the rear bearing and the wall of the crankcase.
Install new pump adapter (5, Figure I-3) into compressor while aligning the mounting
holes for the two flat head screws (4). Install and torque the flat head screws (4) to 5 ft-
lbs (6 Nm).
Install back cover (2) with new cover gasket (3) and secure with two bolts (1). Torque
bolts (1) to 15 ft-lbs (20 Nm).