1. Press a new oil seal into the front bearing cap. Use a sealer on the outer rim of the oil seal. The spring side of the oil seal must face the crankcase when installed. The seal case should be flush to 0.15 mm (.006 in) below the front surface of the bearing cap.
2. Place a new gasket on the crankcase cap mating surface.
3. Apply a small amount of engine oil to the lip of the oil seal. Slide the front bearing cap over the crankshaft end. Do not damage the oil seal.
4. Install the four bearing cap bolts torquing alternately to 13 to 18 N·m (120 to 160 lb ft).
5. Place a new gasket on the rear bearing cap.
6. On air compressors with sleeve-type bearings, slide the rear bearing cap over the crankshaft end. Align the crankshaft and bearing cap so that the bearing cap fits evenly in the crankcase bore.
7. On air compressors with rear ball bearings, slide the rear bearing cap over the ball bearing.
8. Install the four bearing cap bolts torquing alternately to 13 to 18 N·m (120 to 160 lb ft).
9. Ensure the crankshaft turns freely after installing the bearing caps.
10. On air compressors that are bottom oiled, place two new O-rings on the dumb-bell. (Lubricate the dumb-bell with a film of engine oil before assembly). Insert the dumb-bell into the rear of the crankcase and proceed with Step 5 above.