What is the indication(s) of the rear wheel bearings going bad? Is there a test to determine failure?

I have a road noise that seems to be getting worse. Tire kinda guys say it's probably the tires. I've done the front wheel bearings.

There is a lot of miles on that chasis. Just how long will those bearings hold up?

 

That was very vague and nondescript at best.. These cars are sort of road noisy. bearings whine or clunk along..

 

OOp's bad bearings whine or clunk when bad.. forgot that part. My bad.

 

When was the last time you changed the fluid in your rear transaxle? At the very least check the fluid level if the noise is getting worse. A fluid change back there could not hurt.. one last possibility would be a bad CV joint. check the boots back there.. if a boot has a crack it is bad and assume that the joint needs to be repacked. This is sort of an urgent thing if the noise is getting worse.. Hope all this helps.

 

To check the bearings, lift each rear wheel, then try to move it in/out (forward/back)(like checking front ball joints). There should be no movement.

An indication of a really bad bearing in a 951... under hard acceleration, the rear wheel with bad bearing toes-in (enough to slightly push the car's rear to one side), at that time the movement of the rotor slightly spreads the brake pads. The first time you step on the brakes after that, the pedal goes down much further than normal, after one pump it comes back to normal. Not fun and a pain to diagnose.

 

Generally, at first you'll hear a whining or whirring sound, the tone of which is related to speed. If the sound is the same when you lift off the gas, or coasting in neutral or with the clutch in, suspect the wheel bearings. The rears will usually go for quite a while after they start talking to you like that, getting progressively louder over time.

Matt

 

I replaced mine about 4 times in the 28 months I owned my 83. They were not that bad to change. They will make a whirring noise that may be hard to hear as it slowly gets worse and the longer you drive the car, the more you just get used to it.

How many miles on the bearings? If it is a lot, you may just want to assume they are going bad and change them. The parts are cheap and if you do it yourself, the labor is also cheap.

_________________________________

 

Well, the noise is there when rolling and in neutral and increases in frequency as speed increases. I saw in the archives a description as a wump wump wump or something like that.

I replaced the transmission fluid within the past year.

When they go bad, do they just get noisier and noisier, or do they also get sloppy?

The car has 212,000 and some change on it. I can say for sure that those bearings have not been changed in the past 150,000 miles.

 

Definitely change them.

 

Sam; the easiest way I know to check these bearings is just to remove the wheel and grab the stub axle at the nut and shake it. you will know by its sloppyness.Your rear bearing is mounted in an alum arm on the 87 924s and are somewhat more difficult to replace the earlier steel arms.Keep in mind that if you are running snow tires your whine may in deed be from the tires themselves. If you are going to change the tranny fluid make sure the fill plug is out first , as these have a habit of freezing in place and you then strip them out.Then you can't fill the trans after you drain it. HTH

 

Your bearings would have to be very shot to feel or see much play at all. Mine had no discernable play, but they had gotten noisy and were getting worse, and turned out to be clearly bad. The bearings in the steel-armed cars may behave differentlly, I don't know.

 

tabor made a procedure sheet for late model cars. somewhere at <a href="http://porsche.pdxmax.com" target="_blank">http://porsche.pdxmax.com</a>

Anyone have a list for the parts needed for an early model? I believe i ordered the bearings and nothing else. Any help would be appreciated. TIA.

 

We have the early car procedure at Tech-Session:

<a href="http://www.tech-session.com/Paragon/Tech/944_early_rwb.htm" target="_blank">944 Wheel bearing replacement - steel trailing arms</a>

Tabor's will be up there soon also (thanks Tabor!), but for now you can see it on his site:

<a href="http://porsche.pdxmax.com/wheelbearings/index.php" target="_blank">944 Wheel bearing replacement - aluminum trailing arms</a>

Good Luck!

 

Wahoo! Thank's Skip!

<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

You coming up for Dyno day tomorrow, autocross Sunday???

And don't gimme that "too far to drive" crap... Ian's coming from a whole different Country!