Hot Rod Forum banner

12 bolt GM car Pinion seal

5K views 5 replies 5 participants last post by  Overdriv 
#1 · (Edited)
I assembled a 69 vintage GM 12 bolt three years ago for my 68 Chevelle. I have driven it about 10000 miles since and it developed a pinion seal leak recently.

So I pulled the pinion yoke off, pryed out the seal. The sealing edge of the seal was riding right on the very end of the pinion yoke, actually rubbing the inner race of the outer pinion bearing.

See images at end;

The seal used was a National 8460N, the new seal I got from NAPA looks to be exactly like the 8460.

I had installed the seal all the way into the housing till the outer flange touched the housing. That's the way I always had installed Pinion seals in the past.

I measured the seal area in the housing, .500"+/-. The seal also measures .500", so there is little chance of driving it in to far, as one "expert" told me.

So finding a lot of discussion about this very problem on the internet, some say there use to be a different seal for the Truck 12 bolt and Car 12 bolt??

All that seems to be available is the truck seal??

The fix seems to be just leave the 8460 seal out about .125" and be done with it.

So I called around and some didn't know what I was talking about, some said they had seen this before and they just leave the 8460 seal .125" out, which would work without a problem.

But I thought there ought to be a seal out there that would fit correctly without short seating it. There use to be.

One place knew exactly what was going on and they have and sell a seal that they had made just for this problem.

Strange Engineering sells a seal#R5211D that is made with the seal not as deep as the 8460. They also suggested a SFK17627 that would work and I might be able to find it locally. Not where I live.

But anyway, I just wanted to put this out there to see if there is more to this saga and maybe save someone a day of searching.

Comments welcome.
 

Attachments

See less See more
2
#2 ·
The car 12 bolt seal was discontinued years ago. All of the installation kits have the truck seal in them, which works fine in most housings. For about 18 years now I have been leaving the seal sticking out about 1/16th to 1/8th inch on all of the car 12 bolt rear ends that I rebuild. I've had this problem before and I know exactly what you are talking about. I always check the seal to be sure that it isn't making contact with the outer bearing.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top