LSD ok? Rear Bearing collapse....? UPDATED with PICS

[caterhamnut]

I can't find my original thread, but at the Brands Club track day a few months ago, I thought I had broken my diff - a sudden rear wheel lock-up (lots of tyre smoke, brown trousers and relief that it happened coming out of Graham Hill bend and not any of the other high speed corners...)

 

Everything locked up - after some rocking, we were towed off up the paddock, and every now and again the wheels would 'grab' or momentarily lock up again. Engine fine, and in fact car did then drive (slowly) up and down the paddock briefly. Initially we thought perhaps a tooth had broken off the gear ring inside, jammed the thing, then fallen through and freed everything up again.

 

Trailer home, not touched since whilst I try and figure out how I am going to afford a new diff...anyway, today I took the diff (AP Suretrac) out of the car ready to pop it down to Phil at Road & Race Transmissions.

 

All came out easily enough, and indeed the turning of the diff input shaft felt nice and smooth, but no real way of knowing what was going on inside.

 

As I re-assembled the rear hubs assemblies so I could push the car back inside the garage, we noticed that the nearside disc/shaft hardly turned at all - when it did it was very very notchy and stiff.

 

So - new theory is that the rear bearing has collapsed. This caused the nearside wheel to jam solid - the LSD therefore locked the other wheel as well. When towing the car slowly I guess the pressure was off the bearing, which snagged occasionally as the car rolled.

 

Speaking to a few knowledgeable people this evening, apparently this all makes perfect sense, and fingers crossed my only expense is a new rear bearing, and not a new LSD. I'll take the hub apart tomorrow and see what I can see.

 

Anyone else have anything like this happen?

 

I'll just take this opportunity to thank the people who emailed me after my last post with offers of diffs they were selling - much appreciated, hope you have sold them boys - and also to Joachim of MOG, who contacted me right away to offer assistance aswell -

 

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Edited by - angus&tessa on 6 Dec 2008 23:26:59

 

Edited by - angus&tessa on 7 Dec 2008 18:01:00

[Willie.]

Angus,

 

Never had one go in the 7, but have had two wheel bearings go like this before. One in a Capri, one in a Golf. Both happened at low speed and resulted in a lock up/almost lock up (Could hardly steer against it).

 

I'd say the reason it "released" was because it cooled a bit.

 

Wheel bearing sounds like it. Can be a right pig as when they go spectacularly like this, they tend to weld to things and be a right nightmare to get off. Check it hasn't damaged the shaft if it's spun on it.

 

No doubt you'll get her sorted soon enough.

 

Willie

[Rob Walker]

I had two sets fail this year. One set broke up completely on track at Le Mans Bugatti circuit on the Le Sept trip. In my case the wheels would turn and were only held on the car by the rear discs held within the calipers. If they are found to be the fault and fitted within the last two years send them back to CC , they may be part of a faulty batch that they had. I would also advise you to check both sides.

 

I would be surprised if the LSD unit has failed locking the the rear wheels, one of the diff bearings possibly but unlikely.

 

Rob

[Englishmaninwales]

Angus

Same happened to me, I replaced both rear wheel bearing 2 years ago and the n/s failed at 65mph on the A5 near Betws y Coed last July.....heart stopping moment as the car tried to jump into the hedge As Rob says, a faulty batch, apparently. The bearing welded itself onto the drive shaft and I had to cut the bearing and carrier off. I shall replace the potentially faulty off side bearing this winter.

 

Malcolm

[caterhamnut]

Thanks guys - I'll take things apart today and see what I can see, but its good to hear that it 'can' happen as described - not in a 'glad it happened' kind of way, but a 'phew, its not the LSD £££££' kind of way.

 

Having said that, I'm surprised to hear how 'common' it can be - I'd always heard that the rears bearings tended to be solid, as they are not subject to the same stress at the front (in terms if tightening/adjustment etc)

 

We only fitted these bearings at the beginning of the year, although the bearings themselves (already in the carrier/boss) whilst un-used, were actually a few years old...

 

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102,000 miles car

[caterhamnut]

Umm - I think we may just have found the problem!!

 

As we took the half shaft out, this is the sight that greeted us!

here

 

That's not right is it..... 😬

 

here

 

here

 

I reckon this one stopped the car!

here

 

Only problem now is how to get this part of the bearing off the half shaft - note the peaning and ripples on the surface as the roller-bearings thrashed around inside...

here

 

 

 

 

 

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102,000 miles car

[Stationary M25 Traveller]

Ouch - that's not pretty, and not good to hear for little-used parts !

 

 

[Willie.]

Angus,

 

Your best bet is to split it and get it off. Hard to do without wrecking all round you, but I've never had any success with pullers or heat.

 

Angle grinder or cold chisel I'm afraid. Not nice work.

 

Willie

[caterhamnut]

Yep - that is what I intend to do - you can see that trying to get any sort of puller on there will be very difficult, so combination of careful grinding/cutting, heat and chisel!!

 

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102,000 miles car

[Jason Plato]

you could be onto something there Angus 😬

 

here is C7 TOP

Taffia joint AO with Al

 

[Englishmaninwales]

Angus

This is the situation I was faced with ( after grinding the bearing carrier off as it wouldn't come off the driveshaft). I used a dremel with a thin hard cutting disk and cut 2 slots at 180 opposite each other 9/10th through the inner race, and then used a hammer and chisel to finally split it off the driveshaft. Go carefully with the cutting disk to avoid going all the way through and damaging the driveshaft.

 

Malcolm

[caterhamnut]

 

 

Dave - I was going to post one of the pics and ask 'Is this correct....?' 😬

 

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102,000 miles car

[Rob Walker]

Looks very similar to my failure. Check that the disc is not cracked or bent as it will have taken all the side loading when the bearing failed.

[caterhamnut]

- will do.

 

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102,000 miles car

[BBL]

I had a similar failure recently, with a bit over 2,000 miles on my 2006 model year 7, which I just got on the road this year:

http://i321.photobucket.com/albums/nn384/BBL-Sean/7%20Build%20Issues/2011-08bearing01lg.jpg

 

edit -- Hubs/bearings were installed by Freestyle Motorsport, so I assume the installation was properly done.

 

Edited by - BBL on 29 Aug 2011 19:04:55

[Billyboy]

So you favour clockwise doughnuts then..........as you have the evidence to show 😬 😬 😬

 

 

[caterhamnut]

😬 😬

[BBL]

Any suggestions as to the potential cause(s) of such a failure? I want to be sure it is not repeated, as I don't relish the idea of replacing wheel bearings every 2,000 miles or so.

[Stationary M25 Traveller]

Hopefully it was a 1% random failure of a bad bearing ? Dd you fit it yourself, so you know it was fitted correctly ?

[BBL]

No sir; fitted by Freestyle Motorsport.

[Billyboy]

In Angus' case its WEAR AND TEAR 😬 😬 😬 😬 😬

 

But it could be several reasons why yours has died

 

1.Poor fitting (lots of possibilities here)

2.Bad bearing

3.Bearing housing issues (why was the bearing fitted 2k ago and how long had it been in)

4.A one off instance of an impact with a pot hole that did not damge the tyre / wheel but flat spotted a bearing roller

5.Or a combination of some of the above

 

Only way to eliminate most of them is do it yourself

[BBL]

These are the original bearings (from new). Car has a bit over 2k miles in total.

 

Replacement parts are forthcoming, but it would be good to know what caused it to prevent it from happening again. I suppose at this point there is no way to know the cause definitively, and just make double-dog sure I fit the replacement parts properly.

[Billyboy]

So did you get freestyle to build it for you then?

 

But IIRC CC put the bearings in the carrier anyway - mmmm maybe the bearings have been poorly fitted then or at least the bearing race may have been fitted by a Luddite with a big metal hammer and a knackered drift - not the first bearing badly fitted from new -

 

 

Not suffered myself - but others have - sadly though there will be little evidence now unless the race is still not square against the lip of the carrier......