The Stovebolt Site Forums The Parking Lot Big Bolts O-ring size on rear axles

Does anyone know the dash number for the o ring that the inner bearing race seats up against on the rear axles? This on my 56 chevy 6100, nothing is in the manual about it.

I probably have this information for GMC trucks. Do you have ID of the complete rear axle? Below is a list of ALL the rear axles GMC used from 55.2-60.

I do have that information written down so I'll get that tomorrow, I did however find some part numbers and sizes ( two are listed) in the parts catalog. 3707389 - 2 5/8" ID and 3739112 - 2 25/32" ID. The last one is listed as pass. corv. not sure what corv. is... in section 5.819 - 5.830

Those two numbers you listed are for Passenger cars and Corvettes, not a 6100 truck.

This may help. See the attached screenshot with the red box. Those dimensions seem to be close to a -150 size.

I can't believe I missed that one being it's listed right above where I was looking!! Thank you very much, I really appreciate it. Now I know what corv is , didn't see it listed in the abriviations section...

I don't remember any O-rings on the big bolt rear axle, I'm confused about the description, you don't want a bearing race to have any "cushion" or movement that an O-ring might allow.

I believe this is the O ring he is talking about. The black line near the flange. Sits under the inner race. I didn't know it was there until I got to deep cleaning. Also not exactly what function it serves.

Lots of GMC mid-size truck rear axles used this o-ring.

I certainly missed that when I did the brakes on mine. I didn't remove the backing plates, maybe mine are missing?

Doug is correct, you have to remove the inner bearing race to see it therei is a groove cut into the axle tube it sits in , I think the idea was to be certain there would be no weeping of gear lube on the backside of the backing plate near weld... maybe. In searching for hub seal on carters they show a o ring with the seal, so I called them to ask about it two people there said they had no idea why it was pictured with the seal. I did get the seal for cheap on fleabay and have found numerous suppliers for the o ring. Klhansen was on the money for the dash size ( many thanks 😊)

Orings arrived yesterday, at first there appeared to be a discrepancy in size but after removing the old one ( pretty stiff) it had only flattened out. So put the new one on and the inner race seats nicely against it, there is also no machined groove as I thought earlier and still don't understand the purpose of the oring