A1 hub failure

M

moliver

New member
Hey guys I have about 3.5 hours of track time on my 16valve Scirocco and the front axle nut on the passenger side loosened up a bit....caused the wheel bearing to be a blit slopy. I tightened it back up and it took care of the looseness in the wheel bearings. Here is the question, is this the first sign of a hub failure? If not what is the warning sign of a hub failure?
 
Could be if you are certain the nut was tight before you discovered the problem.

A good suggestion is to replace the bearing (and thoroughly check the hub).

Good luck.
 
I am not exactly certain how tight the axle nut was initally but I never felt an slop till last weekend after a session, the next session it rained so I was not pushing the car. This weekend I was searching for the slop and discovered the axle nut was a bit loose, tigtened it up and the slop went away. Now it feels fine.

Thanks for the comments/suggestions.
Mike
 
On our Audi's we tighten (or check) the axle nuts at least once every weekend of racing... we try to replace hubs and bearings at least twice a year... we have had hub failure and found that it is not a pleasent experience... sometimes just before it goes you can "smell" it overheating... (I have never smelt it however my brother smelt a weird smell and pulled into the pits once.... he was lucky to make it back to the garage...) my suggestion is to keep an eye on it... If you have to tighten it again you might want to consider replacing...
 
Do you guys tighten the nut to the proper torque or do you put as much torque on it as possible(long lever and people standing on it)?

Mike
 
The procedure here is to check at least once every weekend, with a long bar and a decently weighted person on the end of it (>190 lbs is pretty good). If you change the hub, we check after every session until the nut doesn't move anymore, and then back to routine checking.

We change hubs before major events, and the take-offs become emergency spares. We haven't had a failure in quite a while.

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Lesley Albin
Over The Limit Racing
Blazen Golden Retrievers
 
All I can add to the Albin's (correct) procedure is to use a top grade synthetic grease (Swepco, Mobil 1, RedLine, etc) This will ensure that should you over heat the bearing you don't cook all the grease out immediately.

PS- On VWs, the factory torque spec is not sufficient for racing.
Blethen's, you may want to try the above technique if you are experiencing failures. Our hubs/bearings last for years this way.


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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment
## 2002 ITB NYSRRC Champs ##
 
Originally posted by moliver:
Hey guys I have about 3.5 hours of track time on my 16valve Scirocco and the front axle nut on the passenger side loosened up a bit....caused the wheel bearing to be a blit slopy. I tightened it back up and it took care of the looseness in the wheel bearings. Here is the question, is this the first sign of a hub failure? If not what is the warning sign of a hub failure?
Click to expand...
I am told that really is no fool proof way to id an incipient hub failure. I had one at Kershaw over Memorial Day at relatively low speed. Before it broke, I was having brake pedal softness (almost no pedal ) then bam! No brakes, and not much drive as it effectively shears it, even with a quaife. Kershaw has good run off areas, thankfully!
Change the hubs after each 3- 4 race weekends to be safe. Torque with an extender and a big guy on the end each race weekend, Per BSI ! I was very lucky!

Rick
 
<font face=\"Verdana, Arial\" size=\"2\">Do you guys tighten the nut to the proper torque or...</font>
Click to expand...

Hub/bearing failures was a consistent problem in the Rabbit Bilstein Cup. The solution was to buy a 3/4" drive breaker bar and appropriate socket, a very long pipe, and find the biggest, meanest, heaviest guy to stand on it prior to each session.

I did the same thing on the SSA Shelby CSX and never had a failure.

GregA
 
Having fought this problem for a long time I did the following.
I made washers that were 1/4" thick and slightly larger than stock. I surface ground them to assure they were flat and then had them hardened.
There are several types of axle nuts. I use the nuts that are the pinch style. Using a Dremel tool I ground slots into the end of the outter CV joint. This way you can stake the nut when you have torqued the nut to spec. Along with using Audi bearings & hubs (5mm larger than VW) I haven't had a hub or bearing failure in two years. (You have to have the uprights machined to accept the Audi stuff)
If you need more information e-mail me.

Chuck Davis
 
Chuck-

Is that legal to run larger Audi bearings in a VW??? If so is it leagal for me to run larger Audi bearings (from a differend year/make) in my Audi???

Raymond
 
The front hubs on an A1 VW have been a known weak link for several years now (they're documented in Greg Raven's book). I use the 'tweak it as much as you can' rule. At home, I have a 3/4" impact gun w/ 150 psi and 80 gallons of air behind it and I make sure I snug it on there good. At the track, I use the breaker bar/pipe/biggest guy I can find method.

At the end of my first season, I had a hub failure. Fortunately, nothing happened other than ruining a stub axle. This was after 4 weekends/6 races. It's pretty cheap insurance to change them out on a regular basis.

Chuck,

I don't think machining the knuckles and using the Audi stuff is legal in IT. I have heard of people getting the hubs cryo-treated (IT legal), and as long as they're torqued enough, they last! Not sure what it costs to get a set of hubs cryo-treated though?

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MARRS #25 ITB Rabbit GTI
SCCA 279608
 
I agree with what everybody has said about getting the nut as tight as possible. Your question was is the hub getting ready to fail? YES . I never have seen the nut just come loose. What is usually happening is the hub has broken inside the bearing, and the stub axle(CV Joint)is holding everything together, or the bearing is failing and the two inner races are wearing into each other. In either case you need to diassemble and look. Also look at the stub, make sure its not been stretched, the crashes don't come from the hub breaking, the come from the stub breaking, which is what is holding the whole assembly together.
 
Originally posted by metalworker:
is the hub getting ready to fail? YES.
Click to expand...


Yeah, we all forgot to mention this part. When the person on the end of the bar reports that the nut moved, and he shouldn't have noticed it moving at all, then it's time to replace the hub NOW, not later.


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Lesley Albin
Over The Limit Racing
Blazen Golden Retrievers
 
Bill,

The rules in IT do not provide for equity...yet. The GCR does require you to have a safe race car. Making mods such as I mentioned using Audi parts for reliability (safety) should never be an issue. Look at the pictures of the A1 cars in this website doing cart wheels.

All, including you who recommend 200 lb. plus torque specs are kidding yourself. Look at the construction of the bearing. Two hardened (and I mean hardened) surfaces matting. 200# is more than adaquate! (Using the synthetic grease as Chris Albin suggests will extend the life of the bearing.) Get or make some good thick flat washers, grind a groove in the end of the stub axle with a Dremel Tool, torque the nut and then stake it....just like Honda does on all of their cars. (They had the same problem with loose axle nuts when they began racing front drive cars.) Your failures will not go away but you'll get to race more weekends without changing out the parts.

The real problem with the early hubs is the transition radius from striaght onto the back surface of the hub. If you reduce that radius it will have more yeild. If you shot pean the surface you will further reduce the tension.

If you choose to be a purest use some early A2 bearings and hubs. You'll have to widen the snap ring groove. Be sure to use the A2 snap rings.

Happy racing!

Chuck Davis
 
Chuck,

Are you kidding me????

You're trying to legitimize cheating because it's a safety issue???? Take that crap down the road!

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MARRS #25 ITB Rabbit GTI
SCCA 279608
 
Originally posted by Bill Miller:
Chuck,

Are you kidding me????

You're trying to legitimize cheating because it's a safety issue???? Take that crap down the road!
Click to expand...
Bill,

I have to be with Chuck on this. Where is improving/correcting an known weak point which can result in very serious consequences, " cheating"? I am not talking "philosophicly" but rather " real world".

No rules nurds please!

Rick
 
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