[dmt335d]

I don't know if anyone can advise but my old mans E60 530I has and issue when braking. Its a 2005 530I Auto with 95K miles.

He picked the car up about 6 months ago and it has been plagued with brake wobble. It had new discs and pads when purchased. After about 5k miles this wobble started happening.

He took the car to a local indy who advised the discs were warped. He then changed them for a new set. This discs were brembo with oem pads. Braking was initially fine but after a few thousand miles the wobble has returned.

He took the car to another indy and they diagnosed the same problem. This time instead of replacing the discs they were machined and new pads were put on, but they did find the hub wasn't running true and replaced that.

The wobble has returned. He's that frustrated he's actually thinking of ditching the car for a replacement. He's taken it down to the last place and they're saying its the discs again. He's thinking of replacing with oem disks and pads but he's not sure that this is the cause of the issue. They're saying the ball joints are ok.. Does anyone have any other ideas why this car is munching through discs?

[parapaul]

Just to clarify -

Since the hub was replaced, have the discs been replaced and/or machined?

If the hub was replaced AFTER the discs were machined to compensate for the runout, that could explain it...

[dmt335d]

Originally Posted by parapaul

Just to clarify -

Since the hub was replaced, have the discs been replaced and/or machined?

If the hub was replaced AFTER the discs were machined to compensate for the runout, that could explain it...

I didn't explain it very well. They machined the disc after they replaced the hub.

[gojonnygo]

I've got this returning wobble after replacing the discs on my E92. (see my thread) I've been trying to get my head round it because it sometimes doesn't do it, but then does seem worse when hot.

I've not changed the hubs yet - but there is abosulutly no play in them, or anything really which is what I can't get my head round - why the wobble...

The only thing I did just before this wobble started was change the front tryes - was a twit fit job - I wonder if wheel balance or even the tryes could set this off.

I'm goind to get hold of a dial guage to see if it could be the hubs but I'm sceptical changing them will be an ultimate fix...

[parapaul]

If it's worse when they're hot, I'd lean towards warped discs rather than anything else.

Bad wheel balancing shouldn't make any difference to braking, wheel wobble presents at a steady speed, usually 60/70/80mph.

[Stringbag]

Bushes.
Check this similar thread out
http://www.e90post.com/forums/showthread.php?t=703852

[westsidee90]

i had the same problem on my mrs e53 i replaced the front arm bushes with powerflex ones which fixed the issue

[dmt335d]

I'll let him know. Apparently the garage checked the bushes but I'm not sure how. Its got to be something like that. Will the worn bushes cause the discs to warp or just simply create the vibration?

[Stringbag]

Possibly both.
Slight disc warp will make the make the bushes work harder - they are being asked to absorb more vibration from the hub. This wears the bushes more quickly and can lead to more warping of the discs. The wobble varies with speed as you can get a harmonic between the two. Also varies with outside temp as the bushes become harder in colder weather. (they are rubber).
Poly bushes get rid of this problem (as does rose jointing) but you loose lots of play in the steering/suspension. Good on track, uncomfortable on UK roads.

[Subzero2003]

First of all, discs very very rarely warp, and almost never do through road use. When people diagnose "warped discs" what they almost always mean is "friction material from the pad has transferred to the disc, meaning that the disc is very slightly not flat". Automatics are particularly susceptible to this as if you come off a motorway onto a slip road - you may have just braked fairly hard from 90mph down to 0mph. This heats the pad massively and then when you are sitting at the traffic lights with your brakes applied, this transfers the pad material slightly to the disc.

Just to confirm, when the various garages have changed the discs, the problem has gone away completely for a few months?

[gojonnygo]

Intersting thought Stringbag...

The intermittant nature of the wobble on my car does suggest there is some harmonic relationship going on. Then once it starts, the bush will heat up and get even worse. It's definatly a sqidgy large bush. And the disks arn't exactly small on a 335 so I suppose the lever arm generated by disk and hub run out could be significant...

So maybe a slightly worn thrust arm bush allows the wheel to twist (out?) slightly warping the disks and possibly also pulling bearing in the hub setting up the vibration over time so replacement of one of these items (hub/brakes/thrust arm) is only a short term fix and eventually the vibration returns.

I'm tempted to replace all three... But if it starts vibrating again I probably cry!

[Stringbag]

Get them checked first - any garage worth its salt will be able to tell you if there is play in the bushes.
The only reason I know quite a bit about it is from my previous car - it was a common fault and I went through 2 sets.
The amount of brake wobble varies significantly with speed & temp.

I have read all the stuff about brake disks not warping, its just deposits etc etc.
It may be partially true but brake disks do warp - you just have to see how a lathe takes material off a disc to see it for yourself.
Not worth it for cheap (ish) discs - cheaper to replace them - but when they are £400 a set it is worth doing!

[HighlandPete]

E39 5-series are known for this wobble, along with the steering shimmy. Assuming all mating faces are perfectly clean and without runout, when new brake parts are fitted, it is most likely soft suspension bushes are contributing to the wobble.

I also go along with the comments that a lot of disc replacements are made when the discs are not really warped. Material transfer can also show up any suspension wear. It is all more sensitive to movement when there is wear or softening bushes.

HighlandPete

[gojonnygo]

I have checked mine - jack up on a 4 post ramp in a fancy workshop with perfect view. Had a play myself and by the mechanic (VW guy) with a pry bar - Everthing is tight apart from the big thrust arm bush - it's what I can only describe as sqidgy - but doesn't seem worn. The design looks like it's supposed to be that way.

But it's very difficult to tell wheather it's a problem with no previous reference. (Without of course taking it to a dealer, which for me is the last resort!) But it's the only thing I can think of that could cause the wheel to twist/move and as it's there to resist the front/rear movement then it's got to be a part of the vibration story... Maybe!

I also can't belive my brand new 5k ago massive ventilated disks could warp - due to heat anyway - I've got a big 4 pot caliper brake upgrade on my TVR and have got them stinking hot on a track with no ill effects, all I've done is dawdle to work and back for the last few months on a duel carraigeway!

When it first started vibrating I tried the disk clean up thing - a couple of big speed stops followed by a cool down period - made no difference. And my disks look brand new - no marks or scoring or anything...

[Stringbag]

Originally Posted by gojonnygo

Everthing is tight apart from the big thrust arm bush - it's what I can only describe as sqidgy

I also can't belive my brand new 5k ago massive ventilated disks could warp -

I agree with you about the discs. Difficult call.
I'd change the bushes if I was you.
How much are they? can you just press out the bush or does it come with the whole arm?

[parapaul]

AFAIK they're part of the arm assembly.

[Stringbag]

How did you get on?

[stuartfung]

Hi,
Was this ever resolved? I have an E90 330D Sport and I am getting the brake vibration when braking at any speed as well.

[CraigUK]

Me too, E91 320D wit a bad judder after replacing all four discs and pads (Pagid). Was OK for the first 1k miles but front judder after that. Only judders once car is warmed up, I've checked the brakes and they aren't binding at all.

[tmarshall57]

This won't be a cure for all of the symptoms reported above but......

After replacing disks and pads all round (Pagid) I was experiencing slight but irritating steering wheel wobble on braking.

I ended up removing the front disks and thoroughly cleaning the mating face between the hub and the disk using wet and dry sandpaper. I did detect that some rust fragments from the rim of the hub had found their way between the disk and hub and cleaning and refitting the disks eliminated the problem.

The wobble was most noticeable after a few miles of driving.

[Subzero2003]

I too am getting this problem when the discs are warm. I too am using pagid pads all round...

could the pagid pads be too harsh for the disc?

[CraigUK]

Are you guys driving automatics? When I get round to it I'm going to take it back to the garage to have it checked out. I was also thinking of taking the pads out and deglazing them to see if it makes any difference.