Chuck Z

I think this issue has reached the point where the fix is definitely beyond my capabilities. Before I take the hub assembly off to have the bearing replaced is there any way to make sure I'm replacing the correct item? From the workshop manuals I attach the following scans for the disassembly of the hub assembly. I don't see where there is a replaceable CV joint at the outer end of the half shaft, am I wrong and could this be the culprit of the noise? How can I know for sure?

algie928s4

Me thinks your in the same place us me, reading that god damn just gets your head spinning, If your getting in over your head I'd stop and re-assemble seek experienced 928 help if possible, if that's not an option I'd take it to a few garages for diagnoses and make up some excuse for not commiting to them fixing it, whilst some things on the 928 are baffling to some mechanics the back end isn't nuclear science so try and get 2 or 3 opinions and settle on that. There's no pint in replacing items on a "MAYBE" instinct.
What you described in your opening post was exactly what I experienced- a loud thud thud thud as if a brick had got stuck in the wheels- CV replacement is quite straight forward, I replaced mine in just over an hour with the right tools a 1 metre power bar being a real help Oh and Jim.
Check your CV boots if ones torn your heading in the right direction, I just don't think the other possible faults are as loud as you describe.

Chuck Z

Thanks for the note. Where I'm getting over my head and beyond my capabilities is removing and then reinstalling a new wheel bearing. I have taken the rear suspension out of the 78 and put it back together successfully so I am familiar with how to do that but I do not have a press to remove the old bearing from the hub carrier and reinstall the new one.

I also want to make sure it is in fact a bearing and not a CV joint. I may have to call someone to come and look at it who knows exactly what they are looking at to confirm bearing or CV joint before I starting taking more pieces off the car.

[edit] The CV boots are in excellent shape.

borland

Noises can emanate and give an illusion of a source that can be deceptive. So it might not be the wheel bearing.

That clicking type of noise is characteristic of a CV joint. As the ***** move back and forth to maintain the "constant velocity", each ball will make one return trip per revolution of the shaft. Sometimes the ball will have a defect (pitting) in one spot making the clicking sound when it gets pushed back along it's somewhat linear track. But looking at your cars registry info, not likely that a CV joint would fail with only 10K miles.

With a wheel bearing, the bearing rollers will rotate several times per wheel revolution, so bearing noise is usually of a low to high pitch noise.

Have you checked the bolts that hold the inside CV joint to the differential? Those are more likely to loosen if improperly installed. That could cause a click too.

Don't let that nut put a stop you from doing the work yourself. I bought a really nice used Snap-On 600 ft-lb torque wrench on eBay for only $300.

borland
90' S4, Slate Metallic

Garth S

Chuck,
If spinning the elevated wheel & listening with a stethoscope to the hub and CV does not pinpoint the issue, then I'd be tempted to remove the halfshaft. You likely know too well the torque on the end nut (#1in the diag), but other than that, it is quite straight forward.
The hub assembly can then be spun freely and examined for end play, a feel of 'gravel' in the bearing - and noise. Ditto for articulation of the CV joint.
This may save further disassembly by decoupling the noise contributors.

BTW - the hub/axle nut comes off nicely with an impact gun, although jumping on a 4' cheater is something to be experienced ...

Bill Ball

If you are lucky, the axle nut was never over torqued. I had a 3 foot cheater and just a few jumps on the end with my 160 lb carcass loosened it up on my 89 when it had 100K miles. Removing the hub carrier is no biggie but getting the old bearing out and pressing in a new one requires a press, an oven and probably prior experience. I left it to a shop to do that part, although I'll never learn how to do it if I keep that up.

Chuck Z

Status update:

I borrowed a stethoscope from Jim Burton at Eurowerks here in Charlotte and listened to the noise through it.

The noise is a grinding gravely popping sounding noise as opposed to the clicking noise I described earlier. It is loudest when I put the probe directly behind the hub underneath the parking brake shoes near the axle as in the first picture. The noise is also very prominent when I put the probe on the outer face of the carrier and not as loud if I put it on the spinning half shaft or boot.

When the car is not running and I spin the wheel I can feel feedback from the grinding in my hands. The hub has no side to side or up and down movement nor does the half shaft. At this point I am heavily leaning toward a bad wheel bearing, what do you guys think. I had DR on the phone at let him listen to it and he commented on how loud it was even when the car was not running and he too suspects a bad wheel bearing.

Almost forgot, when I stick the probe into the hub shaft as in the last picture and touch the sides, I get almost no audible noise through the stethoscope.

That car just has a leaky transaxle no noises from any of the wheels. It's the black 95 with 54k miles with the issue.

Gretch

Be hareful of those spinning bits, they can do you harm......

Chuck Z

I know, I was tightened up all over while listening.

AO

I'd have to guess bearing. But I know you can do it yourself. You may have to send it to DR or someone else to press out/in, but everything else you should be able to do. Don't give up.

Chuck Z

Just got home with a bigger impact wrench and a 32mm socket to take things apart. Ordered a new bearing from DR & Jeannie and taking it to Eurowerks Friday morning to have the bearing replaced. Stay tuned.

Gretch

Go easy, I shattered an impact socket (1&3/16) using 175 PSI in a rattle gun capable of 600FTLBS.....They do break........

Bill Ball

Good thing is your parking brake pads look fresh. :-)

Yeah, bearing is almost certainly it. One of my rears failed suddenly and made a pretty loud but intermittent racket. I only drove on it for a couple of days after the noise appeared. Unfortunately, it partially seized and took out the hub (add $100 for a used hub). I decided to do the other side prophylactically.

AO

Chuck Z

Caution exercised with the impact wrench and everything came out just fine. Actually the 32mm center nut was the easiest to remove. I left the half shaft attached along with the emergency brake cable and the ABS sensor (couldn't get the damn thing out even with DR's guidance)! I'm going to ask Jim at Eurowerks to remove and reinstall any of these items that will need to come off to replace the bearing. I also figured there might a chance he could verify the bad bearing if the half shaft were still attached? Fingers crossed that I'm not replacing a good bearing and still end up replacing the half shaft!