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Discussion Starter · #1 ·
I have been having problems on my Aero with one of the hub nuts coming loose. This causes the wheel bearing to rattle around, which can't be any good for it, and affects the handling as the tracking and camber will be doing their own thing. It only needs to be loose by 1/4 turn for the wheel to rattle around really badly.

After tightening it a couple of times to the specified torque (about 300-odd Nm) and having it loosen again, I bought a new nut and tried again. Well, this morning I checked it and it wasn't quite tight (took 15-30 degrees of turning to torque it up), so that obviously didn't work either.

The next step would be to change the CV joint, as I think that is what the nut threads onto (and change the nut again, of course). That's £75, so I'd be interested to hear any other suggestions. If I were changing the CV joint, I'd do the wheel bearing too as I'm sure it can't be too healthy after all that flapping around.

[edit] Oh, and Abbott racing have already tried threadlock and whacking it up with a compressed air tool.
 

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Just one thing Bill... I seem to recall that the effectiveness of thread-lock is somewhat reduced by dirt/corrosion/grease etc

Torqued to 300NM? Ah well that'll be your problem then. Yoou've got a motor that you (quite rightly) proudly proclaim is pushing out over 330lbft which is circa 450NM. Now, even allowing for transmission losses I should think that will still exceed 300NM at the wheels. Now let me guess... is it the offside hub by any chance....
 

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Discussion Starter · #3 ·
Originally posted by Bubbles (fka Mark E):
[qb]is it the offside hub by any chance....[/qb][/b]
Nope, it's the nearside. I suspect that when the previous nut came loose, it rattled around for long enough to wear the threads on the CV joint a bit. When fitting the new nut, it was stiff to turn (the self-locking thing) until the last few turns, when it freed up quite a lot. I might smack the collar with a punch to tighten it just that bit more.
 

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Bill
Not sure if this will help but here goes. Many years ago my Dad had an old Austin Princess (don't laugh) and had a problem with the hub nut on the off side coming loose. Changed the nut, changed the CV joint all to no avail. Finally we changed the wheel bearing and fitted a new CV joint and nut and that cured it.

Now, I'm not sure if that could be your problem but is the wheel bearing OK. Never done these on a 9000 so not sure if the hub nut compresses the bearing but I guess it is wrth checking.

HTH
Ant
 

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Discussion Starter · #5 ·
Yes, the hub nut seems to compress the bearing, because with the nut only 1/4 turn loose, the bearing flaps about. Perhaps it's shot, although there is no noise and no roughness when turning it by hand.

Thanks, Anthony. It's worth a try if the thump with a punch doesn't work. For the next month or so, if it's still coming loose, I'll simply tighten it up regularly.
 

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Bill, had a car in just the other day that had a new bearing fitted a couple of weeks ago, the hub nut had not been tightened properly and as a result the bearing was already knackered. If you say the nut went loose on the last little bit, I would say the threads have been damaged and the only real cure would probably be to replace CV, bearing and nut. You don't want that nut coming off at speed.

HTH

Neil
 

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Discussion Starter · #7 ·
Originally posted by Neil(9000CS23T):
[qb]I would say the threads have been damaged and the only real cure would probably be to replace CV, bearing and nut.[/qb][/b]
Bu66er

Thanks, Neil.
 

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Absolutely make sure that there is no copper greese (or other lubricant) on the thread or wheel part that the nut butts up against. Loss of friction will make any nut work loose.

As an aside (not casting 'nasturtions' or anything ).. I once heard a mechanic say that "most problems with cars are due to the 'nut behind the wheel'" !!! Ho ho!
 

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As an aside (not casting 'nasturtions' or anything  ).. I once heard a mechanic say that "most problems with cars are due to the 'nut behind the wheel'" !!! Ho ho![/b]
Funny that, I once heard a driver say "most problems with cars are due to the nut using the spanner!"

Trouble is, either way I have no one to blame but myself
 

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Bill
Same my my dad's car. Bearing sounded fine with no roughness. Bearings for the 9000 are pretty easy to change going by the book as they are an assembly complete, so drifting bearings out and in is not necessary. I think they are about £70 a go though.The old trick to test for bearing slop is to shake the suspect wheel top and bottom then get a friend to press the brake hard. If slop disappears, your bearing is shot....but I suppose you knew that.Let us know how you get on.

Ant
 

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Discussion Starter · #11 ·
Originally posted by Anthony B:
[qb]Bill
The old trick to test for bearing slop is to shake the suspect wheel top and bottom[/qb][/b]
There's no slop there when the hub nut is tight. I'll probably replace the lot anyway at some point, just to be sure. Thanks.

The only problem I foresee is that I know that one hub-to-strut bolt on each side is seized solid
This will make things a bit more difficult, but it's time I un-seized them anyway.
 

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Bill, if you can do it safely get some direct heat onto the bolts, (gas torch), as this normally breaks the rust and allows you to turn the nut off without too much trouble. (And without rounding it off).

Neil
 

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Discussion Starter · #13 ·
The nut is fine and comes off easily. It's the bolt that is seized in the swivel hub. I'm told by a Saab mechanic that oxy-acetylene might do it, but a blowlamp won't, as you need to heat up a very large mass of metal very quickly to get the desired effect. I tried the blowlamp, and I think he's right.

I also thought about drilling through the centre, then cutting it from the inside out.

Since I have a backup car, I should be able to spend a couple of evenings over it if necessary.
 

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Discussion Starter · #15 ·
Just an update - I checked the nut again today and it was still tight, but I can't remember how many miles I've done since I last checked it. I've only had to tighten this new one once so far so perhaps it'll be OK. I'll keep an eye on it.
 

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Discussion Starter · #16 ·
Originally posted by Neil(9000CS23T):
[qb]when i said gas-torch, i was actually thinking of oxy acetalene, drilling could take quite a bit of work.[/qb][/b]
Yes, I gathered that's what you meant, but I don't have one, unfortunately. Either way, I can't see it not taking quite a bit of work. The Saab chappie I spoke to didn't seem to think there was any easy way. Even with a gas torch, they still find it difficult, apparently.
 

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one thing to try, give it a really good dose of wd40 or something like that and leave it for a day. Sometimes if left alone it can help a lot. After that try hitting the head of the bolt (square on so as not to damage it ), as it's the rust holding the bolt that you've got to break.

Good luck

Neil
 

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Discussion Starter · #18 ·
Thanks, Neil. I like Plus-Gas, so I'll give that a try. Trouble is, there is about 1.5-2 inches of length to free, and I don't know how far the stuff will penetrate.

Definitely worth another try, though. Cheers.
 

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Two points here.
Firstly hub nuts coming loose. When I got my last 9000 mot'd the tester pointed out thatthere was a little play in the front N/S wheel bearing, not enough to fail it but that I should keep an eye on it. I assumed the bearing was on the way out ,although there was no roughness and bought another. When I got round to changing it I got a long bar on the socket wrench expecting ti to be mega tight and was surprised to find it almost loose.
I fitted the new bearing anyway and torqued it up to the correct torque. A fortnight later I was amazed to find that the there was a hint of play at the new bearing. The nut needed re-torquing. This time I used loctite and it seemed to stay for the remaining few months before the car was written off by a Land Rover up the rear.

The second point is about geting off hub nuts which have seized on. Now 99's used to have the hub nuts loctited on and also the outer edge peened into a grove in the shaft. I once had the experience of undoing one of those loctited nuts using a long bar. The nut came off alright but took the thread from the CV shaft with it


Ever since with such nuts I have used an angle grinder to grind down a flat on the side of the nut until the threads are just showing. One knock with a cold chisel applied in the undoing direction and the nut comes loose.
I ese the same technique for undoing rusted nuts on the exhaust system so that the captive stud on the adjacent section is undamaged.
 
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