Info on rear wheel bearings
 

Hi all! New to this forum. I have a 66 gmc that I have dragged around with me for almost 30 years now and I have started to rebuild it. Long story short, driver side rear wheel bearing and axle look fine and I can replace them np. The passenger side, however, the bearing is badly pitted and the axle is also pitted. Its a HA - 3.73 12 bolt rear end. Here are my q's:

1) do I buff the axle and try and smooth the surface? If so, what is the best way? What to watch out for?
2) I see there are "repair bearings" which incorporate a seal and are suppose to shift the bearing to ride on a newer surface of the axle. Do these actually work?
3) do I run a normal bearing on the pitted axle?
4) do I run a normal replacement on one side and the repair kit on the other or should I keep them matched?
5) bearing brand of choice? Who is the best? Part numbers?

Rockauto only has Centric bearings. The current bearings are Hyatt which where made in Canada.

Thanks in advanced!

Re: Info on rear wheel bearings
 

First, what is an "HA" 3.73 12 bolt? Can you state year of diff and what vehicle it came from? Second, can you post pics of the pitted area in question?

Re: Info on rear wheel bearings
 

HA is stamped on the rear end indicating its a 3.73 gear ratio (i also verified this on the stamp on the crown gear). Its the original, as far as I can tell, from 1966. I don't think my uncle changed it out to something else. There are 12 bolts in the dif cover (not 10). 8.875 inch ring gear without posi.

Bearing dimensions are:
2.531 OD
1.622 ID
0.832 W

Seal:
2.591 OD
1.62 ID
0.5 W

I have been using this to source parts:
https://www.lmctruck.com/1960-66-che...ferential-1-2t

The original truck is a 1966 GMC C1000. My uncle chopped and shortened the frame and put on a GMC 1960's hood and step side box before he gave it to me back in 85'.

I don't have pics handy but will later tonight when I get home and post them up. Thanks for responding!

Re: Info on rear wheel bearings
 

The axle he is describting sounds to me like a Chevrolet full size passenger car from the mid to later 1960's. Most were open rear-ends unless they it ordered along with a high performance engine which then would be positraction/limited slip versions. 12 bolt posi could be ordered in full-size , mid-size and compact cars with higher horsepower engines. The GMC rear-ends are unlike the Chevrolet versions in the way the axles are secured.

Re: Info on rear wheel bearings
 

I was confused also, I thought it would have a Dana 44, like my original 1960 GMC and many GMC's. Does not really matter. If it's Canadian, could have used different diff than USA? (Canadian bearings found and he lives in Canada) "C" 1000.
Steve: It depends on how pitted the shaft is. You could actually ruin the fit by sanding on it, until you reconnoiter the situation. Move cautiously. I don't know anything about repair bearings except it sounds like something I would not want to do.
Don't worry about brand of bearings, even the biggest names are made in China. Just buy a bearing from an auto parts place.

Pitting does not automatically mean it can't be reused. However, at $130, it's better to buy new than to spend anything on them or special bearings. Check around for pricing. Be sure you know your dimensions and spline count

Re: Info on rear wheel bearings
 

Here are the pics. I would not be surprised if my uncle swapped the diff’s between this truck and his chevelle. I will have to ask him next time I see him! The shaft is pretty pitted. I guess I might have to source an axle then or can I get it resurfaced? I might ask around and see as where I work, the mechanics once told me we send bearing housings and shafts out to be spray coated...

Re: Info on rear wheel bearings
 

Here is a pic of the good axle... The VIN is 6C91534818957A which tells me is was a C1000 and an 8 cylinder. There are a couple more numbers: FT069302 PAINT 5306. The HA stamp on the rear end does line up with the documentation for the VIN to be correct as well from what I can tell. Thanks for your help!

Re: Info on rear wheel bearings
 

Hard to tell if the axles are still within spec for OD. Could be worn such that the fit is too loose. The method of fix or replace is up to you. You will spend to get it spray welded and remachined, so see what that cost compared to a new axle and decide of it's worth it.

Re: Info on rear wheel bearings
 

could I interject a different solution here? in the aftermarket auto parts world there is a part known as a repair bearing. basically, it is a extended wheel bearing/seal asm. which repositions both the seal and the bearing further out on the axle shaft and is a self contained unit. I hope I have been of some assistance in this matter. BTW, welcome to the 6066 GMC truck group!

cordially,

Lewis Ellis Matkin, Jr.
Ridge Manor, Fla.
1965 1002 305E-V6(soon to be 401M)

Re: Info on rear wheel bearings
 

Thanks for the help folks!

To buy an axle from the states at $130USD will cost me a bazillion dollars canadian!:ahhhh: On the other hand, I should be able to source one up here. I just am trying to keep costs at bay to get her on the road this spring.

I am also considering the repair bearing and was just wondering if anyone has tried one and if it works. With the shape of my axle, I would be concerned over if the damage also extends into the new bearing path. Also, SKF's R1559TV is a single seal and still gets lube from the rear end where as the Timkin comparable bearing has a double seal. I am thinking one seal is better then 2 as the inner seal would ride on the damaged part of the axle and not last long anyways. I am also thinking on this route as if it doesnt work out the worse case is pull the axle and replace it.

Thanks for the help as always!

Re: Info on rear wheel bearings
 

I have used repair bearings and repair seals when needed and have had no issue with them leaking. As long as the new location is smooth, you should not have an issue. I try to use Moog, Napa or Timkin parts. I stay away from auto part store house brands when I can. I had a leaking front main seal on 350 Chivvy engine that I used a repair seal on and after 15 years it doe not leak.

Re: Info on rear wheel bearings
 

If the axle shaft is pitted in an area where the Timken inner seal wouldn't hold up, then by all means use the SKF bearing. If it isn't, I would use the Timken bearing. You can fill the cavity with wheel bearing grease, and the inner seal will keep the gear oil away from the grease. If you choose the open sided SKF bearing, I then recommend that you overfill the axle with lubricant. This is my reasoning: oil has to migrate down the axle tubes to lubricate the axle bearings. If you only fill the axle to the bottom of the fill hole, the only time oil gets to the bearings in any quanity is when either one side is on a side incline (L or R) or in foam/splash form. When the axle is overfilled (i tell people to cover the bottom half of the fill hole. Fill until lubricant runs out over your thumb, then install the plug). Oil will migrate down the tube, and get to the wheel bearings, eliminating the dry start which can happen. I hope I have been of some assistance.

Re: Info on rear wheel bearings
 

This has been great advice! Thanks everyone!

Re: Info on rear wheel bearings
 

I believe your axle is out of a chevy truck. it has the large axle ends, and the track bar locator for the trailing arm suspension. make sure to measure the length of the axle before ordering, the length of the axle and tube changed in 1967. the complete rear ends are interchangable, but the axle length is different.

Rick

Re: Info on rear wheel bearings
 

The Canadian GMCs of that era were essentially Chevy trucks underneath with GMC bodies on top. See http://www.oeltd.net/doc/6066gmc/VINs/gmc-canada.htm for some Canadian VIN info. As far as I know, the Canadian versions did not come with DANA rear ends. So your rear end could be the factory original rear end.

You might be able to find additional assistance at http://67-72chevytrucks.com/vboard/forumdisplay.php?f=6.

Re: Info on rear wheel bearings
 

Ed Snyder is right, Canadian GMC pickups during the 50's and 60's were Chevy's built in Oshawa with GMC grilles and emblems. Chevy engines, Muncie transmissions, Corporate or Eaton rear axles. What he has there looks like an old Chevy 12 bolt. Lewis Matkin has a good idea, I think there is a repair type bearing available for that axle. But, a good axle shaft should not be to tough to find, even in Canada!

Re: Info on rear wheel bearings
 

Hi Folks! Thanks for the info. I elected to go with the repair bearing for now. I installed it and it seems good. My buddy turned the axle hub face down and cleaned up the bearing surface as best he could. He also found the axle slightly bent which we corrected. I have attached a pre and post pic of the first wheel overhaul with the repair bearing installed which turned out pretty good. Should be able to get it past inspection when it looks like this!