The Stovebolt Site Forums The Parking Lot Tons 'o Fun 1940 GMC AC252 rear axle seals

I went to replace the rear wheels cylinders in this truck that has been sitting 40 years. When removing the hub/drum, the outer seal was shot and there is no inner wheel bearing seal on either side of the truck. I have tried finding seals that fit this truck's description, but no luck. I purchased one from Jim Carter's for a 1 1/2 ton b/c the 1 ton was too small (3 15/16) and the dimensions appeared very close, but was 4 5/8 inches bore versus the 4.5 inches that I have. The inner seal shoulder/shaft is 3.188 with the hub measuring 4.5 inches. There is possibly a seal on the axle housing that has a metal facing w/ a felt backing a little over 1/2 inch thick and measures 4.40 inches in diameter. So this is 0.05 gap between this "seal" and the hub. My brakes were soaked on one side from brake fluid and maybe grease but definitely had grease throughout the drum on the other side where my wheel cylinders did not leak. Also my wheel bearing grease was washed out.


Did these trucks come with a wb seal and the last guy just didn't put them in or did this model use these metal-backed felt seals? I'm afraid my new shoes will be grease soaked in no time.
By the way, the felt ones are inward on the axle housing with the 3.188 inch shoulder described earlier in between it and the bearing and the shoulder is about 1/4 inch deep.

Also, can someone confirm this is a one ton and not a ton and a half...I have been told both but have not had much luck searching the internet for confirmation?


Thanks,

Hilarious

Hy Hilarious Chevy, Merry Christmas, C/R/SKF seal p/n 31855 has the dimensions of I.D. 3.188", O.D. 4.501", width .438" hope that helps.

I’m not familiar with a 1940 model and couldn’t quite follow your descriptions.
Have you looked in the shop manual and the parts manual, were they much help?

Hilarious,
you would probably get an answer from the folks over at OldGMCTrucks.com Old GMC Website

Belated Merry Christmas! I did order these seals just before Christmas from the local auto parts. Thanks for the advice 3B. This is the exact seal I ordered. Hope they work. A stupid question, but I'm not much of mechanic especially when it comes to this old stuff. Did these truck have inner seals to begin with...I would assume so? This is not the first time I've discovered some parts missing or someone improvised on this old firetruck turned farm truck.

Grigg,
I haven't been able to locate a shop manual or parts manual and have been going off an online manual for a 1942 Chevy but still not quite the same. I may just have to bite the bullet and buy one online.


Truckernix,

I have looked on Old GMC Trucks.com but didn't find anything as of yet. I haven't registered on that website, but will.


Thanks for the responses!
Hilarious

1940 GMC repair shop manual.

A much more expensive example is listed on eBay.

Thank you for the link Tim!

Just an update for anyone that cares. I put the modern seals in and everything fits nice with no scrapping and feels smooth. The inner seal seems to fit just fine. I was worried about clearance between the old felt seal and the inner bearing. I did have to tap back the leather backed "seal" a little with the end of a 2x4; so I had enough clearance for the near inner seal to fit. It is a little snugger after I tightened down the adjusting nut like before due to the tight seals, new grease, and it being 20 degrees. Info provided by a poster on OldGMCtrucks.com states the Master parts manual lists the part # 675758 which is a felt seal or a stamped seal with part #2098655. Hopefully this info may help anyone in the future.
Please response if you have any other words of advice,

Thanks,

Hilarious

Thanks for the update.