Rear wheel bearing- getting frustrated...

[yellowline]

I just changed my right rear wheel bearings last week. Everything was great until today, when the old roar came back. Same symptoms, just louder. Seeing as how it initially fixed it, I think there's a problem in the bearing area. Any ideas on what would cause a bearing to roar in less than a week? They were well greased, IMO.

[SoCal Driver]

The axle is worn out. Too much clearence where the inner bearing races sit. How much torq did you put on the nut? Did you use a nes cotter key?

[yellowline]

New cotter pin, torqued to about 300 ft-lbs. Haynes said 280-320, so we got a 150 lb guy with a 2-foot breaker bar.

I was wondering if it had something to do with the axles/ CV joints. I regreased the right side joints since they clunked. They were quite worn, one race was even slightly pitted...perhaps I should regrease them, switch sides, and try to get a little more life out of them.

If it is the axle, do I need to replace the inner bearing again?

[Granite 944]

How do the bearings fit on the axle/stub shaft? Tight? Slip right on? Sloppy fit? MAYBE?

Could be something totally different........who knows? Tire wear/tread design?

"Roar"..........desciption might be better..........hard to say........I feel the pain!

Keep after it........you'll find it! (God knows, I've got my own things to find, that I haven't located the cause exactly yet!).

[yellowline]

OK...as decriptive as I can be...

The noise can first be heard at around 30-35 MPH, it's quite clear and can even be louder than the engine with the windows up and the car in a high gear. Below that, the car is normal, no unusual noises while in motion. The noise is constant...try pronouncing "raaaaaaaaaa" or imagining you're on an old concrete freeway...it's that kind of roar that drives you insane. The noise goes away when you corner to the right, as that corner balances and puts more weight on the left side of the car. Correspondingly, the noise becomes more strident if you put more weight on the right side of the car. Letting the car coast in neutral doesn't help the situation.

An independent Porsche garage wrote "needs right rear wheel bearing" on a work form in 2002. No record of replacement though.

I put new Goodyear Assurance tires on the back end last year. Not high-performance, but Goodyear claimed they were engineered to be quiet. Maybe I should look into having an alignment done? The last indication of an alignment comes from 1998, looking in the records.

[myprsch944]

more than likely its like the first guy said...i just recently replaced my rear wheel bearings, and i found that since i drove with a bad bearing for so long that it wore out the stub axle, although the sound hasnt come back on my car i fear that it mihgt soon.

[SoCal Driver]

When bearings on one side go bad so does the other side. Always replace both sides.

Bad CV joints can be noisy too. Also the bearings on the differential carrior can be noisy.

I've found the roller bearing to wear out faster than the inner ball bearing. Especially if it gets rusty from a bad seal and lots of rain.

[J1NX3D]

are the rear inner and outer the same part numbers as 924 turbo? just wondering since theyre the same brakes, etc...

[924Sman]

Originally posted by yellowline
New cotter pin, torqued to about 300 ft-lbs. Haynes said 280-320, so we got a 150 lb guy with a 2-foot breaker bar.

I was wondering if it had something to do with the axles/ CV joints. I regreased the right side joints since they clunked. They were quite worn, one race was even slightly pitted...perhaps I should regrease them, switch sides, and try to get a little more life out of them.

If it is the axle, do I need to replace the inner bearing again?

Re torque. I am 145 and had a 4 ft bar still does not mean 300 ft lbs! Oh and mine were not torqued enough. Make certain the torque is correct then move on.

[yellowline]

False alarm guys, sorry about that.

The left rear bearing moans very slightly, so I may put that on the to-do list. It just moans when you put it in 5th at lowish RPMs...once you hit 60 or coast in neutral, the back end noises disappear, with the exception of the tires. I don't think I'm going to fool with the transmission to try and fix whatever that is.

Who knows, perhaps a rock wedged itself perfectly in a tire yesterday.

[SoCal Driver]

Results of taking apart a rear stub axle looking for reason it was "moaning":

[bigyagi]

thats some nice heat treatment there SO-CAL

[SoCal Driver]

Broken race was jammed into the rollers and turning in the stub axle.

[Joakim]

I have the same moaning when driving, but when turning to right, moaning is no more.. and when driving straith ahead there it is again...

and when Im fully stopped and get moving again i can hear some noise from RR corner but it is about only 2seconds there and then at 50kmh comes the moaning
(that 2seconds is like someone moves furtitures behind the wall)

I doubt that, that the noise is from brakes

what is that ring called? and where is it?

does it come with the bearings?

Originally Posted by SoCal Driver

Results of taking apart a rear stub axle looking for reason it was "moaning":

[John_AZ]

Joakim,

The early 924 & 944 had the parts.
Here is a picture of the PET of an early 944:




And here are the instructions on how to diagnosis and install.

https://www.*****************.com/kb_results.asp?ID=59

https://www.*****************.com/kb_results.asp?ID=60

GL
John

[Joakim]

How early 924?

i have -81

[John_AZ]

Same.
Here is the link to see for yourself..
Porsche PETs

Porsche Classic Original Parts Catalogue - Classic Genuine Parts & Literature - Porsche Classic - Dr. Ing. h.c. F. Porsche AG

[Joakim]

Originally Posted by Joakim

does it come with the bearings?

if I open rear bearing setup, is it better that I change them then, or does it matter?

[Joakim]

btw can that peace lock the tyre?

today, when I left the parking lot and turned hard right(first turned the wheel to right and then releasing clucths and fealed like that RR tire was dificaltyes to turn..

the feal was like when pushing the square thing around, and it was about few meters
after that it turned normally..

[matthewb]

Originally Posted by 924Sman

Re torque. I am 145 and had a 4 ft bar still does not mean 300 ft lbs! Oh and mine were not torqued enough. Make certain the torque is correct then move on.

You are right, 145 lbs and a 4ft bar would be 580 ft-lbs assuming the bar is perpendicular to the ground and you stand directly at the end.