Fly Navy

My car just started with a new sound and I'm wondering if it might also be a bearing problem. My son riding in the back seat thinks its coming from the driver's rear wheel and I tend to agree from up front. Not a grinding sound though. At the risk, of sounding stupid here goes...not real loud, but noticeable...sounds kind of like a whaa whaa whaa -- sort of like a snow or off-road tire might sound on dry pavement. Noise is not constant, but seems to come when a load is on like going thru a dip in the road or around a bend. Any help out there? Mine's an '87 auto with LSD. Mike

alex70

Mike - for what its worth I had a drivers side rear go bad and sounded like what you are describing. My opinion pretty clear to determine the area and feel of the noise. R/R driver's side rear bearing and all is good. My mechanic said the same thing and I also have 87 LSD - but 5sp.

rich

jon928se

Mike

Your description of the sound reads to me like a rear wheel bearing going bad. As far as the written description of a sound goes - words mean different things to different folks ears LOL

I'ld eliminate the CV joints first though but then if you are going to pull either apart you may as well do the other (bearing/CV joints) anyway.

blown 87

If it is a front bearing the hardest part is getting the grease cap off, we had to use a bearing splitter with a slide hammer to get mine off.
The Porsche seals are different than the napa seals, the porsche seals have a double lip and the napa ones have a single lip.

WallyP

Proper installation of a ball or roller bearing would never have both races a press fit. One or the other should be what is called a "line fit", which means that it should be a light slip fit. That race should be free to slowly (repeat, slowly) rotate. If both races are tight, bearing life will be compromised.

It is poor practice to install new bearings on old races, but it will work in an emergency if the race is perfect and both bearing and race exactly meet the specs for that bearing. If you are doing maintenance on a 928, why not do it right?

Bearing grease is critical to proper operation. When I was active in SAE, I had one friend who was an application engineer for a large bearing company, and another who was an application engineer for a large oil company, with free access to any product that his company made. Both of them used the soft, sticky black grease from Sears in their wheel bearings...

The goal for installing front wheel bearings is to have zero preload and zero end play on the bearings. The easiest way to get that is to tighten the adjusting nut as you rotate the wheel, stop rotation, loosen the nut and tighten it as tight as you can with just your fingers - no tools. Check for end play - if you have zero end play, the bearing is correctly adjusted.

Jim bailey - 928 International

The rear wheel Wha Wha Wha is OFTEN a cupped worn tire MANY of the agressive tread high performance tires when partially worn or unevenly worn will make a wheel bearing like sound. Rear bearings will change the noise/tone as you load unload the rear by going around sweeping corners BUT the worn tire WHA WHA WHA stays much the same.

mark kibort

a couple of tips. Grease cap: a large vice grip levered up and down will get any grease cap off. There is an easy way and a hard way to do these types of things.

you folks will also be entertained to know, Amzoil wheel bearing grease SUCKS. it ooozes out of the bearings and even out of the grease cap when in racing conditions. standard high performance Union 76 wheel bearing grease has "stickiness" it stays in the bearings, doesnt liquify and seems to protect a long long time!!

Mk

Fogey1

Here's an old email post by Wally Plumley.
EDIT: _Then_ I notice Wally's already posted.


From: Wally Plumley <wplumley@bellsouth.net>
Subject: wheel bearing grease-which should NEVER be used

At 01:31 PM 9/5/01, you wrote:
>>"such as "wheel bearing grease" (which should NEVER be used in a wheel >>bearing!)"
>
>Ok, I'll bite. Warum nicht?


"Wheel bearing grease" is still sold only because of tradition. A few years ago, I was very active in SAE (Society of Automotive Engineers). Had several good friends in different automotive areas. Had several discussions on this subject, and there was concurrence on the best stuff to use - Sears Moly grease - the sticky, thin grease that Sears sells in tubes for chassis lube. People agreeing on this included two lubrication application engineers from different oil companies - both agreed that the Sears was the best stuff to use. One commented that he could get anything that his company made for free - but he bought Sears grease for his wheel bearings. Another person agreeing on this was a long-time bearings application engineer.

You want thin grease that will redistribute itself every time that the car is run. Thick grease just gets pushed out of the way and stays there. If the thick grease IS in there, it will lift the rollers and cause skidding, which leads to bearing failure.

Wally

blown 87

It will also bend about half of them so bad that they will leak grease.

The wsm says use a slide hammer.

michael j wright

To get the caps of I normally gently tap them at an angle while rotating the wheel until you can take them off by hand- but AS the women say I do have a soft touch LOL

mark kibort

no bending. ive done it a bunch of times, and it doesnt take much to get them off this way. I dont like a slide hammer as it puts a big side load on a bearing, not designed to support that kind of force. you can pit the bearings this way.

10 years of racing 928s, lots of removing of the caps, and never had a leaking cap. its virtually impossible. probably the most damage to the cap is the pounding of it back on. (denting!)

Mk

mark kibort

another way to determine rear wheel bearing issues is to jack up the rear of the car on stands, get the car in gear, run it up to 4th gear 3000rpms, and then put it in neutral. get out of the car and listen for which side makes more noise. if you have a bad rear bearing, it will be pretty obvious by the noise one side makes.