Rebuilt the motor recently, changed flywheels around after the rebuild. Is banging with a 2x4to get flywheel on and new pilot bearing going to break the rear main seal? I have a rear oil leak that is causing a mess around the flywheel area. Can't tell if it is just the oil pan gasket. Engine is in car and I am already changing the clutch (damn OEM clutch from Autozone)and I'd like to fix this oil leak. I don't want to drop the crank and replace the seal, which means taking off front end to get the timing gear off, etc. I just want opinions on whether or not a rear main seal is hard to break.

 

I don't think you damaged it by banging on the back of the crank. But I'm sure it wasn't good for your thrust bearing. I don't think it was anything fatal.

Rear oil leak can be something as simple as oil pan bolts requiring a retorque, or something more involved. Inproperly installed seal (installed dry, backwards, not offset to parting line), no sealer used on chamferred corners of rear main cap, leaking oil gallery plug, no sealer on the cam bore cap.

Hope it's just loose bolts.

 

engine never leaked before i changed the flywheel etc. just removed the rear main cap. removed seal...there was oil under it.