rear wheel problem (possibly)

[omniruss]

This might be a long withstanding thread depending on my time available before winter, but so far we've been lucky with the weather. Unfortunately my S is not trip-worthy, and I don't even drive it to work (12 miles) because it sounds like another bearing is wearing out. It sounds different (rougher, lower frequency) than diff bearing(s) http://forums.s2kca.com/showthread.php?t=23954 and it seems to be coming from driver-side rear wheel.

I'd like to get a couple ideas before I begin work.

My first hunch is my wheel bearing has never been re-torqued to 220 lbft (I think that's the new spec.) Problem with that notion is that it seems people normally hear a "click" when the car starts to move forward or upon change of direction. I don't get that.

Other than that, I was simply going to take the wheel off and start examining things. I have an excuse for this because I still haven't installed my new Swift springs. Then again I don't want to introduce another variable until I fix the initial problem.

So here's to another "describe what you hear" thread, ugh. It's definitely tied to tire motion. With clutch depressed and car rolling at even 5-10 mph, the sound is discernible. Based on my diff experience, it definitely sounds like rough bearings or pitted cups.

Beyond that, ask me questions and I'll do my best.
Thanks again Dave, and of course, anyone else that chimes in.

Russ

[repiv]

The clicking on change of direction is usually the indication of the onset of bearing problems. This isn't to say that it always happens. You can have a situation where you will hear nothing and the bearing can just go bad without going through the click stage. Once it's gone, there is too much slop for the click to happen. The click is more like the whole bearing shifting inside the hub carrier. A bearing gone bad is usually internalized within the bearing itself.
Bad wheel bearings will typically change their pitch and tone slightly when you load and unload them. This can be done by doing a turn when the sound is evident. If it's the driver's side, then a right hand sweeper will load it up more. Left hander will unload. If it's a dragging brake, this turning test won't alter the sound. Same goes for if it's the CV joint.
As a simple, preliminary test, jack that tire off the ground. Grab the rim spokes at 3 and 9 o'clock and see if there is much movement when you try to wiggle it. Try it at 12 and 6. Give it a really good wiggle without risking knocking the car off the jack.
Does the sound change when you apply the ebrake gently? Do take a look at the brake rotor. Is it scored badly? If you remove the caliper, inspect the pads. Anything odd there? Once you remove the caliper, this will eliminate the rubbing sound you would normally get when you turn the rotor by hand. Turn it and listen for the bad bearing sound. It should be fairly obvious even with no weight on the bearing and at that slow rotation.
Check to make sure the dust shield hasn't been bent in some way and is touching the rotor. Loading that corner won't change this sound.
Did you ever resolve your diff bearing situation? Again loading up that corner won't change the diff sounds much unless it's the LSD. In this case, tight slow figure "8" will be quite revealing. It's not the "loading" of the corner that you're trying to do. You're trying to work the LSD by turning tightly. You don't need to turn so tight to test for the wheel bearing.

[omniruss]

Bad wheel bearings will typically change their pitch and tone slightly when you load and unload them. This can be done by doing a turn when the sound is evident. If it's the driver's side, then a right hand sweeper will load it up more. Left hander will unload. If it's a dragging brake, this turning test won't alter the sound. Same goes for if it's the CV joint.
Tried this test in open parking lot today. I didn't notice any change in pitch or tone as I turned in either direction, wide circles or tight figure-8's.


As a simple, preliminary test, jack that tire off the ground. Grab the rim spokes at 3 and 9 o'clock and see if there is much movement when you try to wiggle it. Try it at 12 and 6. Give it a really good wiggle without risking knocking the car off the jack.
I could not detect any movement (pitch nor yaw)


Does the sound change when you apply the ebrake gently?
No.

Do take a look at the brake rotor. Is it scored badly?
No.

http://forums.s2kca.com/photopost/data/500/medium/DSC05969.JPG

If you remove the caliper, inspect the pads. Anything odd there?
No, plenty of pad.

http://forums.s2kca.com/photopost/data/500/medium/DSC05972.JPG

Once you remove the caliper, this will eliminate the rubbing sound you would normally get when you turn the rotor by hand. Turn it and listen for the bad bearing sound. It should be fairly obvious even with no weight on the bearing and at that slow rotation.
Both rear wheels are currently off, and the driver side caliper is off. When I turn the axle, I don't hear anything alarming. I'm not sure what to listen for. I'll leave the car on the stands for now.

Check to make sure the dust shield hasn't been bent in some way and is touching the rotor. Loading that corner won't change this sound.
Dust shield looks fine.

Did you ever resolve your diff bearing situation? Again loading up that corner won't change the diff sounds much unless it's the LSD. In this case, tight slow figure "8" will be quite revealing. It's not the "loading" of the corner that you're trying to do. You're trying to work the LSD by turning tightly. You don't need to turn so tight to test for the wheel bearing.
My diff was rebuilt by PuddyDad. I am very happy with the outcome. The garage I take my car to doesn't seem to understand the little beast. Before my diff was fixed, first by the garage, then by PuddyDad, it made more of a hissing sound like driving on wet pavement. The sound I got now is a "rougher" tone, so I have some hope that it's not another diff problem.

[repiv]

Tried this test in open parking lot today. I didn't notice any change in pitch or tone as I turned in either direction, wide circles or tight figure-8's.
A parking lot is not a good place to check for wheel bearing problems. The speed and duration is not high enough or long enough. Figure 8s are good for testing the LSD.
A wheel bearing on the way out will produce a lot of heat. You need higher speed and a longer driving trip (at least 30 minutes at highway speeds. It is at these speeds that you do curves to weight and unweight each side to hear any sound differences.
I just came back from having coffee with another S2000 owner who knows he needs a new wheel bearing. In his case, it never did the ticking thing when moving off. His went straight to a constant clicking and then to a howling sound once the bearing gets hot.
If you can give it a good run, then slow down with minimal use of brakes till you come to a stop at the side of the highway, the go feel each rear wheel hub (inside the spokes of the rims). The bad bearing side will feel much hotter than the other side. If they both feel the same, then compare to the front wheel hubs. Be careful not to burn your fingers. They can get quite hot. If you use your brakes too much to stop, then it will be harder to tell.

[omniruss]

Ok, I'll have to put my wheels back on. I've been avoiding highway speeds for any length of time because I know there's something wrong, but that's what you are telling me to do. I'm putting my faith in you, brother! How catastrophic could it be?

[repiv]

Ok, I'll have to put my wheels back on. I've been avoiding highway speeds for any length of time because I know there's something wrong, but that's what you are telling me to do. I'm putting my faith in you, brother! How catastrophic could it be?
If it's bearings, it will get louder and louder as it gets hotter. Once it begins, come to a stop and feel for heat, you can call it a day and go home. You can concentrate on the bearings. If it doesn't get hot or louder, you need to continue the elimination process.
You can run on bad wheel bearings for quite a while and still get the car home at a reduced speed. It's not likely to stop dead in its tracks and leave you stranded. If it's something else, I can't say.

[omniruss]

Just got back from test run. Drove around 70 mph for a good 15 minutes and rev-matched down to a stop. None of the hubs felt warn, front nor rear. But something is howling quite loud, especially at 68 mph. I was unsettled driving at those speeds.

[repiv]

Could still be the diff, but don't eliminate the wheel bearing just yet. Might be time to pull the diff drain plug and take a look at the magnet and the fluid.
You may also need to take someone who knows the sound of a bad wheel bearing and a bad diff, for a ride.

[omniruss]

I had local shop take a look at this... they said it's the diff (AGAIN?! http://forums.s2kca.com/showthread.php?t=23954.)

I'm wondering though, I've seen other posts on here that people had swapped out the diff fluid and problems went away. I change my diff fluid every year, usually in the Spring, and it's that time of year. The diff puts out quite a howl at highway speeds and I find it a stretch that a diff fluid swap would make that much of a difference, what do you think?

If a fluid swap doesn't fix it, then I think the only thing that could be causing my bearings to constantly go bad is that I must've somehow tweaked my diff housing in my accident a couple/three years ago. If that's the case, what do you think would be the best solution?

[repiv]

I had local shop take a look at this... they said it's the diff (AGAIN?! http://forums.s2kca.com/showthread.php?t=23954.)

I'm wondering though, I've seen other posts on here that people had swapped out the diff fluid and problems went away. I change my diff fluid every year, usually in the Spring, and it's that time of year. The diff puts out quite a howl at highway speeds and I find it a stretch that a diff fluid swap would make that much of a difference, what do you think?

If a fluid swap doesn't fix it, then I think the only thing that could be causing my bearings to constantly go bad is that I must've somehow tweaked my diff housing in my accident a couple/three years ago. If that's the case, what do you think would be the best solution?

You should ask PuddyDaddy what he thinks since he provided you with the diff.

The Richmond gear is known for whine. A thicker fluid will mask some of the sound. Doesn't mean it doesn't whine anymore. Just means it's muffling it better.

An accident can explain it.

[desmo4]

If you get some colloidal MoS2 powder and add it to the diff fluid it will quiet down the gears. But i would make sure the diff was set up correctly first.

Jonathan

[S2KPUDDYDAD]

If you get some colloidal MoS2 powder and add it to the diff fluid it will quiet down the gears. But i would make sure the diff was set up correctly first.

Jonathan

I built it, and it was:)

This is some of Russ’s build pics from back in July of 08

The Comptech housing was not fitted very well so, we reground the caps for a better fitment

http://forums.s2kca.com/photopost/data/500/medium/Russ_rebuild_4.jpg

I put in a PuddyMod solid steel sleeve in place of the factory crush sleeve

http://forums.s2kca.com/photopost/data/500/medium/Russ_rebuild_6.jpg

This is the turning torque on the input flange after the PM sleeve is machine fitted, not shimmed

http://forums.s2kca.com/photopost/data/500/medium/Russ_rebuild_7.jpg

The backlash is 3.5 to 4 thousands

http://forums.s2kca.com/photopost/data/500/medium/Russ_rebuild_8.jpg

This is the perfect gear to gear pattern

http://forums.s2kca.com/photopost/data/500/medium/Russ_rebuild_9.jpg

The finished rebuild

http://forums.s2kca.com/photopost/data/500/medium/Russ_rebuild_11.jpg

Sending PM to the op

[omniruss]

Well my diff will be off to PuddyDad soon. Get a load of this caked-up diff plug!
http://i468.photobucket.com/albums/rr41/omniruss/S2000/DSC06129.jpg

[S2KPUDDYDAD]

That is not bad for a year of use. If you rub that with your thumb it will be like cream.
It is normal to have some fuzz on the drain plug every time you change the oil.

Feel free to send in the rear for inspection N/C and if there is an issue with the rear I will take care of it:)

[omniruss]

Just an update... the forward bearing was wearing out, apparently a freak thing to go.
I got my diff back from PuddyDad and installed it last night, then did a short easy drive as prescribed. The diff was very quiet and smooth. :thumbup: