Advice on '75 Rear Wheel Bearings Needed

[Tommy F.]

I'm working the rear of the car....fuel tank, rear suspension etc....

When I removed the rear wheels, it was evident that the rear rotors had been off of the car, and the rear spindles both appear to be aftermarket...( they have a gold colored tint ).

After removing the half shafts, the rear bearings felt smooth, and sounded quiet when rotated...I didn't put a dial indicator on the hub.

Upon removing the spindles to inspect the bearings, the grease was clean (no shavings or grit), the bearings looked good, and the races didn't show any signs of "hot spots"....even the seals looked good and tight. Previous owner can't give me any particulars in terms of when the work may have been done.

Here is the question: clean, repack, and reinstall, or change the bearings and seals with new ones?

[Michael G.]

Re: Advice on '75 Rear Wheel Bearings Needed

Tommy,
I can understand your situation after a favorable visual inspection. The new bearings and seals are not very expensive and you are in a very good position to replace. It would be like swapping out a manual tranny and using the same clutch. You could use the existing bearings and MAY get some long life out of them or you could use new ones and know that you WILL get some life from them. Just my opinion. Best of luck, whichever you choose. Mike

[Michael A.]

Re: Advice on '75 Rear Wheel Bearings Needed

I vote for new bearings and seal!

[Joe L.]

Re: Advice on '75 Rear Wheel Bearings Needed

I'm working the rear of the car....fuel tank, rear suspension etc....

When I removed the rear wheels, it was evident that the rear rotors had been off of the car, and the rear spindles both appear to be aftermarket...( they have a gold colored tint ).

After removing the half shafts, the rear bearings felt smooth, and sounded quiet when rotated...I didn't put a dial indicator on the hub.

Upon removing the spindles to inspect the bearings, the grease was clean (no shavings or grit), the bearings looked good, and the races didn't show any signs of "hot spots"....even the seals looked good and tight. Previous owner can't give me any particulars in terms of when the work may have been done.

Here is the question: clean, repack, and reinstall, or change the bearings and seals with new ones?

Tommy----


Generally, I recommend that the bearings and seals be replaced whenever the rear spindles are disassembled. However, I have a feeling here that these assemblies probably don't have many miles on them. I think that you could just clean and repack them, although I probably would not (I go "overboard" on a lot of things; an old boss of mine used to say I was the master of overkill).

The other advantage of this is that, assuming the end play was right to begin with, you should be able to reassemble them as-is without the need to change shims.

[Tommy F.]

Re: Advice on '75 Rear Wheel Bearings Needed

To tell the truth, the bearing kits and shim assortment have been on the bench for months before I got around to pulling the spindles...just getting "antsy", and figured that I would probably save a day's work by reusing the existing setup....

I guess I knew the right answer was to do it all the way, I havn't cut any corners yet, so I may as well not start now.....

I will assume that the bearing races must be changed with the new bearing sets....driving the old ones out and new ones in with the arms in the car looks like it will be tough.

Anyway, Thanks Guys for the "head check"!

[Jim T.]

Re: Advice on '75 Rear Wheel Bearings Needed

I removed my 68's original rear bearings about 25 years ago with my Kent Moore tools and repacked them and used new seals. Have only driven it about 25K since.

[Gary R.]

Re: Advice on '75 Rear Wheel Bearings Needed

I vote against reusing bearings that were removed. It's easy to damage them removing them. I do a lot of these and never reuse bearings, it's just not worth it. In fact if I find the final endplay is not where I want it then I toss those new bearings out and restart. This is something I've found when using supplied bearings that were just plain cheap.

I use USA Timkens only and never had this issue.
Using new bearings with the same spacer and shim, not fit will usually have a lot of endplay, 010" or more.

Shoot for 0015-002 endplay with oil only for setup. Use a good grease, I no longer use or trust Mobil 1 for bearings. Machine grind the shims and spacers to size, those shim kits sold are too wide in range and some are poorly finished.

If you want the link with a lot of pictures to help you let me know and I'll get it to you.

The original bearings were Hyatt and later New Departure Hyatt (NDH) if you find another brand someone was already in there.

[Steve L.]

Re: Advice on '75 Rear Wheel Bearings Needed

If you change the bearings, you more than likely need to change the shims as well. This means you will need to measure endplay which means you should get the spindle tool. Which also means you will most likely need to grind new shims to do it properly. Or at least get a new set of shims so you can pick the closest useable one.

I wouldn't re-use old bearings since you may have damaged the inner bearing during dissassembly by wacking on the spindle with a hammer. Good re-builders will always change out the bearings.

Once you take this apart, there is no easy way back to do it properly.

[Tommy F.]

Re: Advice on '75 Rear Wheel Bearings Needed

Gary,

I'd love to get the link....this is only my second time doing this...

I am a little concerned about your comment on Mobil 1...

I used Mobil 1 when I rebuilt the my '74 last year, but the car isn't on the road yet....your recommendation?

[Gary R.]

Re: Advice on '75 Rear Wheel Bearings Needed

Tommy
I used Mobil1 on a LOT of T/A's without issue. The last case I bought was different, I called Mobil was told the formulation changed, probably because of all the separation complaints. I used the new and old and didn't like the drag the new caused in the bearings. Removed the new grease and tested the same setup with the old and it was perfect. I wouldn't chance using the new on bearings, both Mobil and Timken suggested using something else. Now I suppose many will argue the point,which is fine, I just won't use it anymore. To each their own.
You can find my work on Digitalcorvettes.com there is a very long thread on T/A's there. If you still can't find it then contact me and I'll get it for you.

[Joe L.]

Re: Advice on '75 Rear Wheel Bearings Needed

Tommy
I used Mobil1 on a LOT of T/A's without issue. The last case I bought was different, I called Mobil was told the formulation changed, probably because of all the separation complaints. I used the new and old and didn't like the drag the new caused in the bearings. Removed the new grease and tested the same setup with the old and it was perfect. I wouldn't chance using the new on bearings, both Mobil and Timken suggested using something else. Now I suppose many will argue the point,which is fine, I just won't use it anymore. To each their own.
You can find my work on Digitalcorvettes.com there is a very long thread on T/A's there. If you still can't find it then contact me and I'll get it for you.

Gary----


As far as GM is concerned, GM #12377985 is the direct successor to the grease GM originally specified for Corvette REAR wheel bearings. GM #1051344 is the lubricant used and specified by GM for FRONT wheel bearings since day one. It's still available from GM, too. I think it's fine for rear wheel bearings, also, even though it's not the grease originally used or specified.

I use Valvoline Synpower full synthetic grease for front and rear wheel bearings.