Rear Axle Seal, National P/N #2081.

[MEP]

Has anyone replaced an 11.5" rear axle hub seal with a National seal, P/N #2081? This seal is different than the GM seal. Its one piece and looks like your ordinary spindle/hub seal that been around forever. The GM seal look like it has 3 pieces, the seal in the hub, a "sleeve" on the spindle and a ring that looks like a grease slinger that WAS pressed into the hub at one time. The National will press into the hub ok, but in order for the seal lip to fit over the spindle, I'll have to pry off the "sleeve". The dimensions of the National seal are: 2.844 x 3.939 x .510 ".

Another question. Are you really supossed to torque the 18 mm caliper mounting bracket bolts to 252 lb-ft as stated in the manual?

[MEP]

I replaced the rear axle seal and bearings (both sides) a few weeks ago. The GM seal came off in 3 pieces. One of these pieces remained on the spindle and you have to remove it in order to instal the National seal. The spindle dia is 2.843 " which is what this seal calls for, www.federal-mogul.com . This cost of the National seal is around $9.00. I believe this seal has been used on GM rear ends since the 70's. I think the GM seal has the inner sleave in order to prevent damage to the seal lip when installing the hub on the spindle at the factory. Here are some pics of what the seals look like.

[jbplock]

MEP,

Good info ... thanks for documenting your results!

:)

[YZF1R]

Good info. My rear seals have been replaced but start leaking after a short time. The parking brake gets progressively worse over time until it barely holds the truck on the slightest grade. I can't believe the number of seal problems reported. I mean, wheel seals have been around for how long? This is the first vehicle I have ever owned with this problem.

Do you or anyone else seem to have taken care of the problem with the National seal? Maybe that's what I need.

BTW, that inner ring looks suspiciously like a speedy sleeve of some sort. Needed to cover up rough machining surface where the seal rides on the axle?

[cowboywildbill]

Sounds like the problem I'm having with my output shaft seal at the transfer case on the front of the rear driveshaft yoke ? I wonder if GM is having issues with the seals in general ?

[MEP]

YZFIR,

The inner piece of the seal is not to cover a worn/rough spindle surface. I believe its purpose was to prevent the seal lip from being damaged during installation of the hub on the spindle at the factory. They probably use a robotic arm that installs the hub on the spindle. When you install the National seal, that inner piece has to be pryed off the spindle with two screw drivers. (It comes right off.) The ID of the ring is faced with rubber (nitrile). I think its this interface, between the inner ring and the spindle, thats the source of the leakage. Maybe if installing an OEM seal, (say because you had a zillion miles on your rear axle and had a groove worn in the spindle), I would apply some sort of sealer to the inner ring where its contacts the spindl.

BTY, if you go the web site of Federal Mogul, www.federal-mogul.com , look under their parts catalog section for detailed application information.

[YZF1R]

MEP, thanks for the reply. If that's what National says that seal is for, that suits me. Guess I'll have to put those in. I'm just going to try to clean up the parking brake pads, as they are so expensive to replace.

Thanks again,
Steve

[Turbo Al]

Yes you are correct LOL I used 2081 seals when I rebuilt the rear end of my 1993 so they have been used for quite some time.
Al