Premature REAR wheel bearing failure?

[Knestis]

We are having ongoing problems keeping rear wheel bearings in the Golf III - like to the point that we can kill one in a long weekend on the track...

Last year, we put in a new set, checked and adjusted them once early in the season, then left them alone for the entire year. Because I didn't plan very well, we used cheap-o grease from the local Part-O-Rama or whatever. We had no problems, finishing the year with the VIR 13 hours.

THIS year, we put in new bearings at the beginning of the year and killed both sides after one track day and a NASA 3.5 hour endurolette. Howwwwwl. Grease was Amsoil synthetic - nice and red when it went in but it came out looking like aluminum antiseize. They were installed and adjusted by the same two guys, using the "zero torque," screw-driver-side-push Bentley manual method.

Since then, we've replaced them - what? - four times? Including during the Summit 12 Hour this past weekend. I've tried several manufacturers, from cheap online mailorder places, my reliable friends at Bildon, and the local VW store. We even replaced the stub axles, thinking that maybe they were bent and putting offset loads on the rollers.

Most of the ones we did in this year were under stock alloys and 5mm spacers.

Any ideas out there? Anyone else seeing this kind of problem? We've had some suggestions but I'd love more input.

K

[Ron Earp]

Doesn't seem like that bearing would get huge abuse with a FWD but....you are racing and not driving to work.

What size bearing is it? Could it be overloaded? I would bet that someone around here has the SAE guidelines handy for bearing loading and could give a rough calculation if it is in the ballpark or not.

Beyond that I would guess the lubericant is failing. What is the drip point of the grease used? Additives?

I think your installation method is correct and what I have always used.

But, I have known fellows to torque the hell out of the retaining nut, which I would think would cause failure quickly, only to watch them last indefinitely.

I'm a little perplexed as well.

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Ron Earp
NC Region
Ford Lightning
RF GT40 Replica
White Jensen-Healey ITS
Silver "Skull" 260Z ITS
Email: "rlearp at gt40s.com"

[Ryan Williams]

When I install the rear drum or rear disc, I "preload" the rear bearings and then release the preload by slightly backing the large retaining nut. Then I adjust the right amount of torque using the Bentley screwdriver procedure.

Have you changed anything in the rear braking system (ie bias valve, etc.)that would cause the rear pads to drag on the discs, creating a lot of heat buildup on the discs and bearings?

[VW16VRacer]

Kirk

I had a inner rear wheel bearing go bad two weeks ago at Seattle. After a race at PIR, that I didn't hear any noise, the first warm up in Sat morning the thing was just howling. I, like you put a fresh set in every season and these were only 3 races old. They were all German FAG bearings. I cut the cage off and had about 1/3 of the inner race was chewed up, like the hardening went away. I had the replace it with a NAPA bearing from Mexico. I am also running 5mm spacers.

Now I have been using the Swepco syn grease and have had very good luck with it. I haven't hit any FIA curbs, gone off track or hit a pot hole with this wheel. Just seems to of gone bad.

Is it a inner or outter bearing? Is it a inner or outter race? Any off track stuff it could be blamed on? I think our last conversation noted not a bunch of rear camber on the rear. Is the bearing race blued from heat or are the rollers blued?

Jon

[JamesB]

New here but which amsoil grease are you using? Each one has a specific heat range thats its good for. The Race series 2000 is a very high temp polymer compared to the standard all purpose.

Also given the car, where is the toe and camber settings on the car. As stated above that could be putting undue stress.

Have you had any excursions right before this started that could have tweaked the rear beam or has the rear thrust and alignment been checked since then?

[OTLimit]

Kirk,
Chris says he hasn't had any problems with the rear bearings.

Good luck finding the problem.



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Lesley Albin
Over The Limit Racing
Blazen Golden Retrievers

[Bill Miller]

This was the outer bearing and the inner race. When Cameron and I changed it at the 12 hr, the grease that came out looked like anti-sieze, as Kirk mentioned. When I did a post-mortum on it (didn't cut it apart. Kirk, did you save it?), the race that was installed in the drum, had all the chrome missing. When you put the beaing in the race, and put any side load on it, while turning it, it felt like there was sand inside.

As a side note, ~20 min. before we brought the car in, it had been in for a pit stop and driver change. The L/R bearing was loose as shit!! There was so much wobble in the wheel, I can't believe it didn't break the stub axle. We tightened it up, but when Kirk went out, he immediately reported that it was howling, and we brought him in as soon as we could get set up to change it.

I've never had problems w/ rear wheel bearings on an A1 (fronts are a whole other story). I'm stumped by this one.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

[Fastfred92]

Sorry but I dont think the rears are on the ground enough on the SSB VR6 ( same brgs, I think )to ever wear out.... I did have some problems in the old ITA Golf III but a switch to Red Line grease and a slightly tighter axle nut setting cured it..... I also hear that Mobil 1 wb grease is good from my trans am buddies



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Fred Alphin
#92 Hankook Tire SSB VW GTI VR6
BMW 325i ITS ( 2006 ? )

[Knestis]

We checked before the enduro and the car had zero toe and 1.5* negative camber.

I confess that I don't know which Amsoil grease we were using.

I'd forgotten but when we put in the set before the enduro (brand new when we started the 12 Hours), we did do that preload thing, snugging them up before backing them off to the zero torque setting.

It's the inner (larger diameter) units that have been failing. I actually re-used an outer on one side when we got the wrong ID parts in one of our kits. The outer ones have never indicated that they are a problem.

I didn't save the dead ones from SP but in looking at the others that crapped out, I don't remember them being discolored from being overheated. They just looked like they'd been grinding themselves to junk.

There were a few curb hits on this last set but nothing really horrific, I don't think.

The huge looseness that Bill describes developed during the race: We checked them several times during the test/practice/qualifying day and there were fine.

Thanks for all of the thinking, folks. If you have other ideas, let me know. I'm intrigued by Jon's comment, that he had a similar failure. I'm beginning to wonder if, in reality, all of these parts are being made in one factory - regardless of how they are labeled - and they are having QA issues...

K

[VW16VRacer]

Kirk

18 years in wrenching on German cars, 9 of them with a Mercedes Benz dealer and 3 with an Audi dealer, let me be one of the first to tell you that we have seen a number of "bad lots" or "bad run" parts. Audi had a run of bad replacement timing belt tensioners bearings going bad in 5-8K after repplacing them, I replaced a couple of motors because of it. Try a different brand, SKF, Timkin.... You may have to go to a bearing supply store to get what you need.

Jon

[Mark LaBarre]

I've always used Mobil 1 synthetic grease and never had an issue on my A1.
Maybe the races aren't installed right. Your not re-using the same races, are you?

[joeg]

Amsoil's best synthetic race grease is white--not red.

I suspect a badly made bearing (perhaps an odd occurance)and would change brands.

Regards.

[Bill Miller]

It's the inner (larger diameter) units that have been failing. I actually re-used an outer on one side when we got the wrong ID parts in one of our kits. The outer ones have never indicated that they are a problem.

Kirk,

This was indeed the outer (small diameter) bearing that failed. While I didn't give it as thorough a look as I did the outer, the inner one appeared to be fine.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

[racer_tim]

Very strange indeed. I've never had a bearing faluire, but I use pure old "Moly B" grey grease that I got when I was in the Air Force.

Haven't have a rear bearing failure yet. Like Bill said, the fronts are another story, but I can't blame the bearing for my failure, it most likely was this that caused the hub / failure

http://linerud.myvnc.com/racing/videos/sea...-two-wheels.avi



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html

racer_tim @ yahoo dot com

[sccaITA16v]

Kirk, congrats on the win, I was a driver in the silver ITA scirocco 16v. (we broke early and retired) Like a lot of the above posts, i've never seen this failure, either. I change my rear bearings once a season and use Mobil 1 grease. Regardless, I "pretension" the bearing by taking a 24mm socket to the nut and grabbing it with my hand, tighten it as far as it will go, back-off it, do it again and then put on the cage and cotter pin. Hope this input helps.

Larry
MARRS ITA #32

[Eric Parham]

I had a similar problem once, and I eventually figured out that it was a defective brake drum.

Here's how it went: I had replaced bearings and races on one side two weekends in a row, at the track, mostly with screwdrivers and hammers. Also replaced the stub axle once. All sythetic grease using the preload-release-fingertight-spin install method. Just didn't make sense that so many were failing. I threw a used drum with 100K old bearings on and it worked great for the rest of the season.

That winter, I went to "freshen up" the removed drum with new bearings using better tools and taking more time, and what I discovered was that the outer bearing race seat in the drum was slightly oval, and that the inner bearing race seat in the drum was slightly canted. It had been the defective brake drum causing the inner bearing to wobble and fail and the outer bearing to flex and fail.

Since I discovered one drum with two different defects, imagine how many drums must have at least one defect!

[Knestis]

I confess that I never considered the rotor but this problem has crossed over two sets of them. I guesst that they may have come from the same lot or something but we're currently banking on the too-tight theory. More as we learn it.

K

[madrabbit15]

Kirk,

I have been racking my brain thinking about your deal and because you have already gone through so many parts from different companies, I would have to think that maybe your problem DOES have to do with how tight you have that bearing. When we first started racing everything that we read told us to tighten that nut tighter than what we have found works best. Now we can go two seasons without replacin bearings and even then it is just for good measure. They still look perfect when they come out. Let us know how it goes.

Derek

[Bildon]

Is the dirt seal in place and tight?

These are street cars. Follow the factory guidelines...
VW says tighten the nut to the point where the thick washer under the spindle nut can just barely be moved with a flat blade screwdriver. Place the "crown" with cotter pin back in so that this clearence is maintained.
(For the benefit of those new to car mechanics, that "crown" is not symetrical. You can rotate it to find the point where the cotter pin will insert without having to tighten or loosen the nut)

Do not keep tightening it as you put laps on the car. The rear wheels always have a bit 'o play in them. Think low drag

As mentioned above the rears should last for YEARS even on an IT endurance car.

Check those rotors for bad race seats or if the races themselves have not been replaced, replace them ASAP.

This is an odd one Kirk!.

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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment

[Bill Miller]

Bill,

We put new races in the rotor when we did the change. I'm really at a loss on this one.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608