View Full Version : Rear Main Seal

Phantom Menace
03-08-2003, 08:20 PM
My engine was rebuilt last year and when it was done the new rear main seal leaked a bit. We just replaced it again and it appears to be leaking again. Are these seals problematic on our cars or is there some trick I don't know about.:confused:

XR7 Dave
03-08-2003, 08:58 PM
The crankshaft likely has a wear ring in it that is preventing the seals from working correctly. You can get a replacement sleeve that goes over the end of the crank to give you a new sealing surface, but I don't know what it's called or where to get it. Ask your machinist.

Phantom Menace
03-08-2003, 09:49 PM
Dave, thanks for the quick reply. I'll check into that first thing Monday morning.

06-23-2003, 05:54 AM
I just had a complete long block installed a little under 14,000 miles ago. I blew a trans line on the way to Carlisle and cooked the fluid a little from slippage due to fluid loss. Bob Simpson of the NJTACC really helped me out as well as doing a great job fixing the leak. I had the fluid and filter changed at Jacob's Service Center in N. Smithfield, RI. While they were checking for leaks from the trans pan after reinstalling it they told me my rear main seal was leaking a little. Should this be leaking so soon? I might be mistaken, but wouldn't that have been a new part not transfered from the previous engine. The cause for the new long block was a broken crank (snapped at first journal). Is this a common problem for SC's or should my car be rechristened as "Jinx"? I mean this is the 3rd engine in under 100,000 miles, and most of the guys and gals I've talked to in various forums on this board have gone at least 70,000 plus with just the typical HG problems. Aside from a little fun now and then, I don't drive my car as hard as people think I do. I don't baby it, but I don't beat on it either. At the very least I expected the previous engine to outlast my tires! Any ideas?

06-23-2003, 12:25 PM
The most comon devices I've heard of are called Speedi-Sleeves. Though I think that is a trademarked name by Chicago Rawhide, it's a bit like Kleenix, and ones from various manufacturers are similarly identified.


There is also similar devices that are Wear Sleeves, designed to allow for wear, but they are physically thicker, and could require a different seal to allow it to fit.

These are common on over the road trucks for use on Input and output shafts as well as drive axles.

06-23-2003, 12:53 PM
While you have the transmission off the rear to the motor, check for crank end and side play. Put a dial indicator on the crank and try to move it (prybar). If it moves more than .008" in and out or more than .006" up and down it will likely be hard to seal.

If the clearances were not checked on assembly this crank movement will result and soon wear out any seal, even if the journal is sleeved.