Ok folks, I need the masters to chime in here. heard some louder than normal howling on the way home from laguna. though it may be tire rub, or maybe a wheel bearing going south. went on a unloaded run (no tires, tools, jack, parts, or the reast of the 700lbs i take to the track in the car) car is still fast, 60-100mph 6 seconds, but at 100mph down to 50 or so, there is a howling noise. little lower frequency than my front wheel bearing that went a few years ago. kind of the same sound like those howling tires, you know, Yokohama AO32R DOT race rubber!

Anyway, jacked the rear of the car up and put it on jack stands and ran the car up to 120mph indicated and turned off the engine. put a stethascope on both shock bottoms, and the ITS THE DRIVER SIDE!! Now, transmission near CV joint is pretty quiet, on both sides. however , if its the CV joint at the wheel, this could be the problem too. sure sounds like the wheel bearing and it is really loud when listening with the scope. passenger side barely makes noise listening with the scope .

Now the question, can a rear wheel bearing last very long when making some noise?? what does a CV joint failure sound like ( or better said, leading up to a failure)

How hard is it to remove the S4 or 85-86 rear hub and replace that pressed in wheel bearing?

HELP!! only have a couple of weeks until Infinion Raceway ITE SCCA Race!

thanks,

Mark

 

Mark, CVs click , they don't 'howl or growl'. They also almost never go bad unless the boot is ripped. As a CV joint gets worse it will progressively 'click' louder and louder until it completely fails. Conversely, in nuetral, with the joint 'unloaded' but the wheels spinning, the clicking will stop.

I'd lay money on you needing rear bearings(they DO growl when going bad, and get louder as the problem gets worse. Normally they will make noise for a loooong time before ultimate failure, but no need to take chances with a high end race car like yours!). It's a fairly simple job(especially by 928 standards- so straight forward in fact that i don't even remember what was specifically involved, lol). The only annoying part is securing a 3/4" torque wrench(very pricey piece of equipment for a good one that you can trust to read accurately, ie Snap-On or Mac- well into the several thousands of dollars- try to borrow one).

If you can't get the bearing out yourself, just take it to a machine shop and they'll remove/press the new one for you.

 

Bearings howl.

You seriously put the car to 120 and got out and layed underneath to listen? Are you nuts?

 

I tried out for the spiderman role, but i looked too old!

yes, on jackstands, layed out, put scope on the bottom of the shock and near the hub as the wheels coasted down. (I think its like 1800rpm at the wheels and winds down to 900rpm at 60-70mph or something) those 50lb 335s and kinesis are a little intimitating though.

so, it sounds like wheel bearings.

great! guess it could be worse. CV joints too!!

Mk

 

Rhetorical question Brendan?

Mark, if you've got a bearing or anything making that kind of noise, it can't wait. You could putt around town for quite a while like that, but the way you drive it's got to be fixed. You would NOT want that wheel locking up at 130MPH! A quick check would be a dial indicator with a magnetic base attached to the lower control arm and indicating against the rim edge. Wiggle and check the play. Compare to the other side. If it's bad, you won't need an indicator to tell the difference.

Also, while CV joints will usually click when they fail, they can also growl and vibrate when worn. BTDT. In my case I'm positive that was the whole problem, as I didn't even have to pull the wheels to change all 4 CV joints -- nothing else changed and the growl went away. One way you can check them is to have the car on ramps and trans in neutral. Grab the transaxle output flange on the side that you want to check and rotate back and forth while you slide the halfshaft back and forth along the axis. If there is a lot of rotational play at any point in the halfshaft's movement, try to narrow down whether it's the inner or outer joint -- or both -- so you can decide what needs replacing. Don't do this with the wheels in the air as the various parts will not be in the position where they normally wear.

 

Does the noise vary when in turns? It should if it is the bearing. Getting the carrier off is easy. I've done it. Getting the old bearing out and the new one in requres a press and an oven to heat the carrier. I left that to the shop.

Note if the bearing is partially seized it can destroy the hub. Mine did.

 

Mark, I had the same problem two weeks ago on the Euro. Both rear bearings were dead (dry and some play on the driver side). You need a press and a torch to remove and assemble the bearings. Took me 30mn for the bearings assembly. Did a 2:33.2 at RA with those bearings..........
Jean-Louis
91GT, 87S4, 84 Euro S (GT2s)

 

Pull the halfshaft on that side, lift the caliper clear of the rotor - and spin the wheel (after reattaching). The bearing is now isolated and wear/play can be determined.
You have to do this much teardown anyway - so 'decouple' the potential noise sources to better diagnose.

 

Replace them in pairs.

Garrity

 

"Also, while CV joints will usually click when they fail, they can also growl and vibrate when worn."

I've never run across a 'growling' CV joint in several years as a tech, but i suppose anything is possible.

 

In my case, there was grit in the joint which caused abnormal wear and the wear surfaces were spalled. So, the rough wear surfaces caused the growling. Usually when these things wear, they do so over an extended time period and they stay smooth. So the first symptom is excessive play, which manifests as clicking. Any sort of CV, bearing, etc. can howl or growl if there are rough surfaces in contact with one another.

 

Was your boot ripped?

Just curious.

 

I had a driver side rear wheel bearing howl. Picked it up on my way back home from a track day. The howl would start at around 50mph. Didn't change in pitch with increased speed, just got a little louder. When I got the spindle off the car, the bearings (they are huge) felt pretty crunchy. Had the new bearings pressed in at a machine shop, hmmm.... still feels crunchy. Installed it any and the howl was gone.

Sounds like a bearing to me Mark.

 

Yep... bought it that way. No way I would have let it get like that.

 

Wow, same thing . on the way home from laguna's race, started to hear it at 50mph , just like you and it got louder and louder going to 70,80 and 90mph for a quick test. it would howl alll the way down to about 50 and then you really counldnt hear it that loudly.

i wonder if its worth touching the CV joints, at least for test. their boots and even the shaft looks brand new. no rip or tears. heck, i dont think the holbert car has seen rain but one or two times! sounds like their noise , if bad would be different.

MK