Rear wheel bearing on 84

[Walter F.]

I tried entering my 84 at a SCCA event just for some fun. At the inspection station I was told my cars rear wheel bearing were warn and to dangerous to let me on the track. I never have replaced the bearings on a Corvette. Is it as easy as a regular rear wheel drive car or are special tools needed. I have a FSM and what i am reading on page 3D4 seems to imply that tool J-34161 is needed to remove the hub and mounting bolts. Since i am not a great mechanic but have some knowledge and have done a lot of things myself on this car mostly with the engine (replaced lifters, distributor, etc) is this type of job dealing with independant rear suspension best left for a professional?

[Joe L.]

Re: Rear wheel bearing on 84

I tried entering my 84 at a SCCA event just for some fun. At the inspection station I was told my cars rear wheel bearing were warn and to dangerous to let me on the track. I never have replaced the bearings on a Corvette. Is it as easy as a regular rear wheel drive car or are special tools needed. I have a FSM and what i am reading on page 3D4 seems to imply that tool J-34161 is needed to remove the hub and mounting bolts. Since i am not a great mechanic but have some knowledge and have done a lot of things myself on this car mostly with the engine (replaced lifters, distributor, etc) is this type of job dealing with independant rear suspension best left for a professional?

Walter------

These bearings are completely sealed, bolt-on assemblies. The GM part number for your application is GM #7470501 and costs about 300 bucks, discount-priced. They are not too difficult to replace but there are other parts that have to be removed to get at the bearing assembly.

[Patrick H.]

Re: Rear wheel bearing on 84

Quite a bit less money if you go non-GM though...

http://www.amazon.com/GMB-730-0206-W...productDetails

Even a Timken is just over $100.

[Jim L.]

Re: Rear wheel bearing on 84

I have a FSM and what i am reading on page 3D4 seems to imply that tool J-34161 is needed to remove the hub and mounting bolts.

I don't know what that tool is so I can't advise you regarding it. I have, however, replaced C4 rear (and front) wheel bearings a couple of times. My observations:

You need a 36mm socket and a T-55 Torx bit.

After you remove the brake calipers and rotors, use the 36m socket to remove the nut which secures the bearing hub to the stub axle.

There is no need to undo the U-joints at the inboard end of the stub axle. Doing so is just extra work.

Use the T-55 Torx bit to remove three bolts which secure the bearing hub. These are accessible from the inboard side of the bearing mount. A wobble extension on the Torx bit will prove helpful.

Work the bearing hub loose from the splines of the stub axle and it will come off in your hands.

Installation of the new hub is the just the reverse of the above procedure. Be sure to replace the cotter pin which retains the stub axle nut.

This really is a simple job. Heck, I figured it out and didn't have the benefit of a shop manual. If I can do it, darn near anyone can.

Jim

Edit: I'm leery of Timken bearings. I had a pair of front Timken bearing hubs fail immediately after installation. It could have been and probably was "just one of those things", but when I replaced the Timkens I went to a different brand.

[Dick W.]

Re: Rear wheel bearing on 84

Quite a bit less money if you go non-GM though...

http://www.amazon.com/GMB-730-0206-W...productDetails

Even a Timken is just over $100.

Timken or SKF available at Rock Auto for about $100.00

[Bill H.]

Re: Rear wheel bearing on 84

Walter, your bearings must have been really shot to have the SCCA Tech line with the car on the ground (I do these inspections for SCCA). Hope you will check all the bearings since the one is bad, it should be done with a dial indicator, the procedure is in the FSM. Jim's write up is good, you might want to hit the Torx bolts with penetrating oil the day before. There have been some other complaints on the Timken's especially with guys who track their cars. I'd also stay away from the off brands especially if you're going to hit the track. I'd stay with the stock GM units or upgrade to the SKF bearings. There's also some Tommy Morrison rear wheel bearings out there for sale, they are a GM part that were used on the Corvette Challenge cars.

[Dick W.]

Re: Rear wheel bearing on 84

Be interesting to see whose bearings are in the AC Delco replacements, being that they do not make anything anymore but catalogs.

[Jim L.]

Re: Rear wheel bearing on 84

Walter, your bearings must have been really shot to have the SCCA Tech line with the car on the ground (I do these inspections for SCCA).

No kidding. I've been through SCCA tech and not once has anyone looked at wheel bearings. Catch cans, safety wire, harness dates, previous log book entries..... never bearings.

Hope you will check all the bearings since the one is bad, it should be done with a dial indicator,

About 10 years ago, when I first became acquainted with C4 bearings and suspension, word on the street was that the rear bearing hubs had reliability issues. May or may not have been true. Regardless, I always checked the bearings for radial and axial play with a dial indicator. As I recall, when one of the two measurements crept up to about .003 - .005, it was time to change the hubs.

There have been some other complaints on the Timken's especially with guys who track their cars.

How very interesting. The set of Timkens that failed for me did so within about 20 miles of being installed. Being brand new, they were the last thing I suspected when I experienced a loss of my front brakes (an unsettling discovery to make when trying to slow for Thunderhill's turn 10).

How did a failed set of bearings make my brakes go away? With an extreme amount of play, they allowed the rotor to wobble and knock the caliper pistons back in the bore. First push of the pedal went nearly to the floor as the pistons were pushed back out into contact with rotor.

I'd stay with the stock GM units or upgrade to the SKF bearings.

I replaced the Timkens with 'Murriken made SKF assemblies and had no more problems.

Jim

[Joe L.]

Re: Rear wheel bearing on 84

Quite a bit less money if you go non-GM though...

http://www.amazon.com/GMB-730-0206-W...productDetails

Even a Timken is just over $100.

Patrick------

Here's the problem: when I see such a wide difference in price between GM and the aftermarket and, especially, between GM at deep discount and the aftermarket, I begin to wonder if there is not a big quality difference. Of course, it's possible there is not but it's also possible there is.

[Joe L.]

Re: Rear wheel bearing on 84

Be interesting to see whose bearings are in the AC Delco replacements, being that they do not make anything anymore but catalogs.

Dick------


There is no doubt that the GM bearings are manufactured by one of the major bearing manufacturers. The question is whether that bearing manufacturer manufactures the bearings they supply to GM exactly the same as the ones they sell in the aftermarket under their own brand or other brands. To discern if there is a difference one would need to carefully compare the GM bearing with the one made by the same manufacturer but sold in the aftermarket. If they are EXACTLY the same in EVERY respect, the chances are they are the same, "through-and-through". I'll bet they're not, though.

One more curious thing: the GM rear bearing assembly is still sold under the same part number as when GM's NDH Division was making them, probably in Sandusky, OH. Usually, when GM shifts a manufacturing source, and virtually always when they shift the design of the part to the new manufacturer's design (even though it might be very similar to the GM design), the part number changes.

[Dick W.]

Re: Rear wheel bearing on 84

Patrick------

Here's the problem: when I see such a wide difference in price between GM and the aftermarket and, especially, between GM at deep discount and the aftermarket, I begin to wonder if there is not a big quality difference. Of course, it's possible there is not but it's also possible there is.

Joe, when we had the parts business, we saw major price differences in the identical parts, down to the manufacturer. One piece would be in GM/AC-Delco box, and the other would be in an aftermarket supplier (which was the OEM supplier to begin with). I doubt that SKF is in any way inferior to the AC products.

[Bill H.]

Re: Rear wheel bearing on 84

No kidding. I've been through SCCA tech and not once has anyone looked at wheel bearings. Catch cans, safety wire, harness dates, previous log book entries..... never bearings.




About 10 years ago, when I first became acquainted with C4 bearings and suspension, word on the street was that the rear bearing hubs had reliability issues. May or may not have been true. Regardless, I always checked the bearings for radial and axial play with a dial indicator. As I recall, when one of the two measurements crept up to about .003 - .005, it was time to change the hubs.


.

Jim

I have my tech guys grb the top of the wheels and give them a good pull, that's about all you can do with the car on the ground. I had my 92 on the Reno track last weekend, @ 96k miles, the original bearings are still at .002, go figure.

[Wayne W.]

Re: Rear wheel bearing on 84

Such a vast improvement over the earlier cars. Wheel bearings and brakes on the C2-C3 will keep you in business, but I have never changed a C4 wheel bearing in the 20 years since they were produced, except for those that have been slammed against a curb.

As for a manufacturer for GM supplying a different bearing for GM and a lesser quality under their own name, I doubt that. What would be gained by selling an inferior product under your own name?

[Dick W.]

Re: Rear wheel bearing on 84

Such a vast improvement over the earlier cars. Wheel bearings and brakes on the C2-C3 will keep you in business, but I have never changed a C4 wheel bearing in the 20 years since they were produced, except for those that have been slammed against a curb.

As for a manufacturer for GM supplying a different bearing for GM and a lesser quality under their own name, I doubt that. What would be gained by selling an inferior product under your own name?

Did not intend to indicate they were of lesser quality, just cheaper price

[Joe L.]

Re: Rear wheel bearing on 84

Such a vast improvement over the earlier cars. Wheel bearings and brakes on the C2-C3 will keep you in business, but I have never changed a C4 wheel bearing in the 20 years since they were produced, except for those that have been slammed against a curb.

As for a manufacturer for GM supplying a different bearing for GM and a lesser quality under their own name, I doubt that. What would be gained by selling an inferior product under your own name?

Wayne------

It's like this: there is often a difference between OEM and aftermarket parts. OEM parts are sold into an, essentially, "non-competitive" market place (except for the sort of competition between franchised dealers that's prevailed for the last 15 years, or so). Aftermarket parts are sold into a marketplace where price means everything. Very often OEM parts are not even manufactured in the same manufacturing plants where aftermarket parts of the same manufacturer are produced. Aftermarket parts are not necessarily "bad" parts. They simply are cheaper made to satisfy the price requirements of the aftermarket. Also, keep in mind that aftermarket parts usually do not have to last as long as OEM because by the time they are installed on a car, a lot of the car's life is already "used up".

GM, itself, sells both OEM and aftermarket quality parts. Those parts available through franchised GM dealers' parts departments are usually OEM. However, GM also has the Delco parts system. This is primarily an aftermarket parts system. Sometimes, OEM-quality parts will be available through the Delco parts system. If so, they will carry the same GM LONG NUMBER (6, 7, or 8 digits) as the part available through franchised GM dealers. They may or may not also have a Delco system part number (usually a hyphenated part number or an alpha-numeric part number. If an OEM part is available through Delco it will often carry a price that's about what one could buy the part with a wholesale discount through franchised GM dealers.

Delco also sells aftermarket-quality parts and, sometimes, several grades of parts for the the exact same application. "Delco Professional" is their top aftermarket grade. These parts sell for less than the OEM parts. That does not mean that they are "junk", though---it just means that they are not the same quality as the OEM part. These parts will carry either no GM long number or they will have a GM long number which is different than the OEM part for the same application.

I believe that other manufacturers do exactly the same thing. In other words, they may supply OEM quality parts to GM but manufacture and sell a lower grade part in the aftermarket. In fact, it has to be this way because, as it's been pointed out, GM does not manufacture many parts anymore. So, they are getting their OEM parts and their Delco aftermarket parts from outside suppliers and, most likely, the same manufacturers are making both lines of parts.