3 rear main seal failures in 1 year

I have a 93 civic lx 1.5L. I had a bad rear main seal leak 1 year ago and had the seal replaced. It lasted maybe 7 months and then i had it replaced again. Now it is in the shop again for the seal leaking again. The mechanic and i are trying to figure out what the problem is here. Anyone have any ideas why a rear seal would repeatedly fail?

could be several things.. mis-alignment during installation, although highly unlikely to happen repeatedly...

the seal housing could be bad
the transmission input shaft bearing could be bad, which would cause excessive vibration, which could lead to bad seal.

There are probably other things, but those are the basics.

Also, excessive crank/flywheel/clutch assy. vibration could cause the seal to get damaged, and eventually start leaking again.

There is always option "D"... your mechanic isn't fixing the real problem, and is just screwing you over, knowing you'll keep coming back to him.

I had been thinking of having him check for crankshaft endplay.

The input shaft bearing is a good idea that i will suggest checking.

All of the repairs since the very first are on his dime so he is loosing out on the deal but i would still like to be done with it.

Thanks for your ideas Dr0pZ0n3!

np
always here to help... in such a cynical way.

I had the mechanic check the crankshaft end play and it was out of spec. So he replaced the thrust washer. No more failures!!

thanks for the update!!