19 replies to this topic

[Ozymandias]

I've had something of a saga with my passenger-side front wheel juddering under braking ever since I had the wheel bearings replaced.

 

The Mini has been back and forth to the (hopeless) garage and has had new bearings, discs, pads and a new drive flange.

 

This seemed to fix the problem, but soon the juddering was back so I decided to try and sort things out myself because the garage has been so clueless.

 

On inspection it seemed that the brake disc was warped, as I could see it moving unevenly against the pads. Brand new discs, still it moved unevenly, so I replaced the drive flange (again!) with a brand new one. Still the disc moves unevenly - and there's no play or movement in the bearings.

 

I'm presuming that the only thing left that could cause this problem would be the drive shaft itself, so I plan to get a new one (if anyone thinks I'm wrong, please tell me!!)

 

Question is, do I need the short or long drive shaft for the near (passenger)- side front wheel?

[Carlos W]

I don't think the drive shaft would cause the symptoms you're describing. 

 

I wonder if a damaged CV joint would though?

[firstforward]

I trust the large castle nut on the drive shaft has been torqued up using the correct procedure? It has to be torqued up with a special sized washer, undone and re-torqued with the cone washer in place.

[nicklouse]

a faulty dive shaft would not do anything that you say. a drive shaft can break. or strip its splines neither would have any effect on the wheel or brake.

 

a CV joint also unlikely, as it is just a carrier in the bearings.

 

crud between the drive flange and rotor can cause issues. incorrect installation of the bearings also.

 

then there is the possibility that the problem is not there but on any of the other wheels and they are providing the feed back in the pedal but as that wheel is the one that has been worked on you are now fixated on that one being the issue.

[Ozymandias]

Thanks for your replies!

 

I've torqued up the castle nut properly, as far as I can tell.

 

Nicklouse, I take your point about the bearings being incorrectly fitted (although the garage maintained that there was "no way of fitting them incorrectly", but I take that with a large pinch of salt). I'll have a look at these - but couldn't the drive shaft cause the flange and disc to rotate out of true if (say) it was slightly bent out of shape at one end?

 

It's true I'm fixated on that wheel - but that's because it's the one with the wobbly disc

[nicklouse]

 but couldn't the drive shaft cause the flange and disc to rotate out of true if (say) it was slightly bent out of shape at one end?

 

 

nope as it has no bearing on the wheel. remove the drive shaft and the wheel will still rotate just the same.

 

if the CVs are worn you can get some shacking of the drive shaft but a bent drive shaft is very unlikely and would have been felt before.

[ibrooks]

Nope - the driveshaft can't affect the disc in that way. It's connected to the disc via a flexible joint that accounts for the angles it moves through as the suspension rises and falls and the steering is turned so any bend in the driveshaft would be lost in that movement. As an example the front wheels on a GTM Coupe or Rossa use the Mini hub, bearings, drive-flange, brakes and CV joint exactly as they are used in a Mini - but there's no driveshaft in the back of the CV.

 

My money is on the bearings not having been fitted properly - i.e. seated with the big flat washer mentioned before being assembled with the cone shaped washer.

 

It's just possible that a bent CV joint could cause the problem. If it's bent along it's shaft and therefore the drive-flange and the bearing seat on the CV are no longer parallel when it's bolted up. It's one hell of a beefy chunk of metal to have bent and I'd have expected to see witness marks on the back of the drive flange and the bearing seat on the CV itself. I'd also expect it to kill the bearings in a few miles. I've never seen one bent like this but it woud fit the theory.

 

Is there any run-out on the drive-flange face that the wheel bolts up to or is it just at the disc?

 

Might be worth sticking a location in your profile and you may find someone local who would be prepared to look at it and give a second opinion or even help fix it properly.

 

Iain

[Ozymandias]

Hmmm... there's no noise coming from the CV joints, even on hard lock.

 

I can't see if there's any run-out on the flange - but I'm hoping that both flange and disc should be fine, as I've replaced them twice!!

 

The problem only started after the (provenly not very competent) garage fitted new bearings - so maybe they have fitted them incorrectly (although they said there was no way this could happen)...?

[Dan]

Have you measured the runout at the disc? Are you judging this just by looking at the gap to the pads in the calliper? There is an acceptable amount of runout, a couple of mm or so isn't a problem. Juddering under braking is normally a suspension problem in reality and in a Mini is normally caused by worn out tie rod bushes or bent tie rods.

No a bent shaft or joint can't really cause this because it would not affect just the disc but the whole CV joint and so the wheel bearing and hub. It would as such either jam the bearing or cause judder all the time.

[Ozymandias]

Could it be the bearings being incorrectly fitted? The problem only started when the garage replaced them...

[nicklouse]

Could be.

[ibrooks]

When you fit new wheel bearings (or arguably even if you've just had them slackened off to do something else like replace a disc/drive-flange) you need to re-assemble the whole lot with a special flat washer rather than the cone-shaped one and torque the hub nut up. Then you remove the hub nut and flat washer, refit the cone shaped washer without disturbing the bearings and finally torque them back up and fit the split pin. If you don't do this (and many don't as it's not obviously necessary unless you read a manual) the cone shaped washer can get a grip on the CV's shaft and whilst the hub nut makes it's torque setting the bearings are not seated/loaded correctly and can wobble.

 

This is what we're betting has happened on your car.

 

Depending on how friendly the garage still think you are with them you could try asking them if you could borrow the flat washer that they used as it's a beefy bit of kit so generally kept around for the job. If they don't have one then how did they do the job properly?

 

Iain

[Carlos W]

Depending on how friendly the garage still think you are with them you could try asking them if you could borrow the flat washer that they used as it's a beefy bit of kit so generally kept around for the job. If they don't have one then how did they do the job properly?

 

Iain

 

This is an excellent idea.

[Ozymandias]

When you fit new wheel bearings (or arguably even if you've just had them slackened off to do something else like replace a disc/drive-flange) you need to re-assemble the whole lot with a special flat washer rather than the cone-shaped one and torque the hub nut up. Then you remove the hub nut and flat washer, refit the cone shaped washer without disturbing the bearings and finally torque them back up and fit the split pin. If you don't do this (and many don't as it's not obviously necessary unless you read a manual) the cone shaped washer can get a grip on the CV's shaft and whilst the hub nut makes it's torque setting the bearings are not seated/loaded correctly and can wobble.

 

This is what we're betting has happened on your car.

 

Depending on how friendly the garage still think you are with them you could try asking them if you could borrow the flat washer that they used as it's a beefy bit of kit so generally kept around for the job. If they don't have one then how did they do the job properly?

 

Iain

This would make an enormous amount of sense. I'm not really on speaking terms with the garage anymore - is there anywhere I can get hold of the washer separately?

[Ozymandias]

 

When you fit new wheel bearings (or arguably even if you've just had them slackened off to do something else like replace a disc/drive-flange) you need to re-assemble the whole lot with a special flat washer rather than the cone-shaped one and torque the hub nut up. Then you remove the hub nut and flat washer, refit the cone shaped washer without disturbing the bearings and finally torque them back up and fit the split pin. If you don't do this (and many don't as it's not obviously necessary unless you read a manual) the cone shaped washer can get a grip on the CV's shaft and whilst the hub nut makes it's torque setting the bearings are not seated/loaded correctly and can wobble.

 

This is what we're betting has happened on your car.

 

Depending on how friendly the garage still think you are with them you could try asking them if you could borrow the flat washer that they used as it's a beefy bit of kit so generally kept around for the job. If they don't have one then how did they do the job properly?

 

Iain

This would make an enormous amount of sense. I'm not really on speaking terms with the garage anymore - is there anywhere I can get hold of the washer separately?

 

Found one on Minispares - not cheap for a blummen' washer, but it was there and I need it! ;)