rear wheel bearing assy

**Wayne P.** · April 23, 2007, 06:22 AM

Re: rear wheel bearing assy

When cornering, opposite sides of the differential turn at a different rate. The u-joints will not be in phase except by happen chance.

**Michael W.** · April 23, 2007, 06:50 AM

Re: rear wheel bearing assy

Dave,

You mentioned your car has only 47K miles- why does it have two new trailing arms and now needs a new backing plate and maybe new bearings? Something doesn't add up. If your only real sign of things being amiss is the appearance of the backing plate, I would leave well enough alone.

AS previously stated, it's normal for the u-joints on opposite sides of the car to end up out of phase. That's why it's called a 'differential'.:)

**Terry F.** · April 23, 2007, 09:05 AM

Re: rear wheel bearing assy

Your backing plates should be silver cad plated, not silver zinc or gold zinc or gold cad. There is one small difference as far as the backing plates go that I am aware of. There are small part number characters and there are large part number characters. Though I am not certain of this observation, I tend to see the small characters on the C2 and 68/69 corvette. There seems to be a transition to larger characters in the later year corvette. I like to watch for this little tid bit of information but so many cars get there backing plates tossed, it is hard to tell any more. I was trying to figure out if there was some consistancy to this observation. Maybe someone will read this and know. Terry

**Chuck S.** · April 23, 2007, 11:58 AM

Re: rear wheel bearing assy

I don't know of any way to tell if the rear wheel bearings have been replaced...maybe not even when you have removed them from the spindle support and are holding them in your hand. Only the bearing numbers are likely to be the same; the control arm assembly supplier could purchase from several bearing manufacturers back in those days

The only way you can tell if the bearings are relatively new, or very used, is from the CONDITION of the bearing (discolored, scoring, brinneled, etc.)...if they have mechanical defects in the rollers, you replace them. If you are simply repacking and adjusting the rear bearings, you would reuse the bearings if they are free of defects. If clean lubrication is maintained (read regular inspection, packing, and readjustment), the wheel bearings should last forever.

Because the external appearance of the spindle support, or external housing, is old and weathered does not mean the bearings are old. In fact, if you were forced to replace one spindle support and control arm because of a catastrophic bearing failure, you may or may not replace the bearings in the OTHER side, but you would be a fool not to inspect and rebuild the other side. If there is any evidence of overheating, scoring etc., you would HAVE to replace the bearings, but otherwise, if they are in good condition, maybe you reuse them.

At that mileage, and with a bearing failure on one side (failure relatively recently; you can still tell the control arm is new), I expect the bearings on both sides needed replacement and hopefully they were smart enough to recognize that need. Since having rear control arms rebuilt is expensive, and one of them is new, I would probably be inclined toward putting a few more miles on the car before having them serviced again. Having said that, whenever you buy a C2 or C3 that you plan to drive a lot, and don't know the maintenance history of the car, the SAFE approach is to have the rear control arms serviced soon.

**David M.** · April 23, 2007, 09:36 PM

Re: rear wheel bearing assy

Dahhh, I was thinking about the u-joint phase Q on the way to work this morning, dahhh the car has to go around the corner. Thats what I get for late night surfing after a long day and working on to many single shafted vehicles.
These arms are new(er), but the bearing/spindle assy on the left is not? My main objective was to replace just the plate because it looks like crap and at one time the shoes and linkage ripped into it probably from worn e-brake shoes and over adjustment. Its been a while since I've had my hands on a vette rear end, its all coming back now!
I think its service time.
Chuck, I definitely agree if I was in that far I would have done both sides. I also agree with the statement of better safe than sorry especially not knowing this cars service history. I was hoping to avoid that until the end of this cruz season but I'd rather feel safe and check, repack and adjust.
As always, this site is worth its weight in gold. Thanks to all. Dave

**Joe L.** · April 24, 2007, 01:29 AM

Re: rear wheel bearing assy

Dave-----

FUNCTIONALLY, there is no difference between the later plates and the earlier ones. ALL 1965-82 rear disc brake backing plates are interchangeable. In fact, all years were all the same part numbers (left and right side are different, of course, though).

Later plates don't have the Delco-Moraine logo on them.

The plates can be changed without having to dis-assemble the bearing unit (i.e. remove the spindle from the spindle support). However, to do it one must remove the parking brake assembly with the spindle in place. This can be tricky, but it can be done. Once the parking brake assembly is removed, the 4 nuts retaining the studs can be removed from the rear of the trailing arm and the spindle support assembly removed from the trailing arm, releasing the backing plate.

**Chuck S.** · April 24, 2007, 10:03 AM

I Have A Similar Story...

When I started restoring my 70, the rear control arms were the first major component to come off the car...the "how to be sucked into a frame off restoration" is another LONG story. Anyway, after the control arms were disassembled, I learned that one of the spindle supports was cast dated in 1972...clearly, it was a non-original part and had been replaced somewhere, somehow, but why?

Years later, I came into the original owner's maintenance history, and in the receipts was one for towing and repair/replacement of one rear control arm, spindle support, etc. They also did the other side...losing a rear wheel bearing and spindle must have been a clarifying experience for him.

It appears my car's original owner didn't know that the rear wheel bearings had to be serviced regularly, and had driven the car 57684 miles before he found out the hard way. A later receipt showed that he had the rear wheel bearings (AND front wheel bearings) replaced again at about 87000 miles. For an additional 30k miles, replacing the rear wheel bearings was probably overkill, but he had clearly learned his lesson, and was erring on the side of safety.

**David M.** · April 25, 2007, 08:32 PM

Re: rear wheel bearing assy

Joe, Tricky is a subtle way of describing the E-brake shoe installation with said spindle in place. I just did the "good" side. Luckly I've been wrenchin' for many years and thus have learned feness and patience.
Excellent info regarding the backing plate. I thought it could be done this way but I wasn't sure. I don't have a good exploded view of this assembly, gonna surf the net tonight for one. Last 3, C3s I restored I replaced it all as an assembly. For this car I need to find a Chilton's service manual since it will be a long relationship.
Chuck, great story I think it may be worth a call to the last owner, Though I don't like to bother him because he had to give up this car for medical bills so hes not too happy to discuss much.
Has any one ever used that greasing tool the resto houses for greasing the rear bearings? Any feed back?
Thank you all for taking your time to reply. Dave.

rear wheel bearing assy

rear wheel bearing assy

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