[MWA]

Originally Posted by DrEvilPorkchop

I remember reading in BMWCar magazine someone had a M3 (e92) with the same problem. This was caused by his wheels - he'd had them refurbished at some point and after this it caused the same problem that you are having.

Have you had your wheels refurbished recently?

Could it be from curbing?

[MWA]

Originally Posted by HighlandPete

Too much paint is often blamed for preventing heat transfer. The wheel is part of the heat sink for the discs. If the hub and mating surface are painted and insulating the 'joint' in the assembly, it can add to disc heat levels.

Personally I question the discs have definitely warped. Many a disc gets changed and there is no distortion at all to the discs. One possible cause is material transfer from the pads, causing uneven braking through the disc rotation.

Contamination and corrosion can also cause brake judder.

The question I ask is, are the discs all shiny and bright, or showing signs of surface issues?

A surface like this can cause judder.



HighlandPete

Thanks for the info Pete, the new and the old discs were both shiny and showed/shown no sign of any wear and tear. As good as new.

[MWA]

Originally Posted by teaston

This makes more sense! Unless he's taking the car on a track i just don't see how the brakes could get anywhere near hot enough to warp, especially this time of year!

Have you tried doing a hard brake bed in MWA ?

(After they've been normally bed in for a few hundred miles of course)

I tried hard braking on the first set and that only made matters worse by loads!

Am scared of thrashing it this time in case they're somehow are tracking it, since they've given the car back to me

[teaston]

Originally Posted by MWA

I tried hard braking on the first set and that only made matters worse by loads!

Am scared of thrashing it this time in case they're somehow are tracking it, since they've given the car back to me

Bizarre!

[Kal101]

Very bizarre indeed.
Not sure if surface rust would cause that much of an issue as sometimes get surface rust on my discs when the car is left standing around for a few days. They get a lovely golden brown colour which goes after a few brakes. But never had any of the symptoms described above.
Did get that on my earlier volvo on the second set of upgrade discs and pads ( black diamond vented and grooved with predator pro pads). But a change soon fixed that not to reappear
The re occurrence is strange. Still wondering On the faulty batch theory.

[Daftasabrush]

You may find this an interesting read: http://www.stoptech.com/technical-su...nd-other-myths

Stoptech do know a thing or two about brakes...

[Chris Peacock]

I'm at 69k miles and still on the original discs and pads, not had a single problem with them so does sound very strange.

[Mattyk]

Originally Posted by Daftasabrush

You may find this an interesting read: http://www.stoptech.com/technical-su...nd-other-myths

Stoptech do know a thing or two about brakes...

So it would seem, scared to use my brakes now for fear of misuse

Good article

[HighlandPete]

Originally Posted by Daftasabrush

You may find this an interesting read: http://www.stoptech.com/technical-su...nd-other-myths

Stoptech do know a thing or two about brakes...

It is articles like this and other expert comment in the trade, which still make me question whether the discs really are warped.

Often users who have discs replaced because "they are warped" have the same issues again.

Dealer may have to look closer for other causes.

HighlandPete

[pete18]

I would not leave the car in Park at lights etc, does it not have Hold

[....,,,,..,,..]

Originally Posted by HighlandPete

It is articles like this and other expert comment in the trade, which still make me question whether the discs really are warped.

Often users who have discs replaced because "they are warped" have the same issues again.

Dealer may have to look closer for other causes.

HighlandPete

+1 there seems to be a knee jerk reaction at garages to brake issues and inevitably its 'your discs are warped'.

They very rarely look at what actually caused the warping (if was present) and just replace.

[Steven1077]

Just put a clock on them and you will soon know if they're warped

[SkyJawa]

I think I've got the same issue, 10,500 miles in 11 months old a just driven back from Manc and the juddered every time I used them, in some cases a judder in others a pulsing sensation as pulling to a stop. Think I'll have to put it in but of on hols next week in it so gonna have to wait

[spyro512]

I'm suffering the same issue. Did you get this solved?

My car (320iX M Sport with 340mm rotors) started vibrating while braking at ~40.000km. Not sure if it used to vibrate without braking; I think it didn't, but can't recall now as I was not paying attention to that.

Swapped the rotors to Zimmermanns + pads (TRW) and 2000km later the vibration came back. There was also a noticeable vibration at 140km/h without braking and a clearly audible noise of friction, but I guess it's because the perforated discs are just noisier.

Swapped again to Zimmermanns (this time just flat rotors, not perforated) + also swapped the hubs. Pads stayed the same as the last time, as there were new (TRW).

The test drive was incredibly good, very smooth. But the car started to vibrate again while cruising at ~130km/h after only 30km. It's very slight, barely noticeable, but it's there and it will get worse for sure. No friction sound at the moment.

I lifted the car and if I rotate the tires while lifted, there is a point where it needs slightly more force.

Any ideas? You guys think that the pads might be guilty this time? They didn't solve anything when I changed them before, therefore I assume the pads are not guilty.

[danb1979]

Not always discs (brake discs don't warp); it's either pad deposits, badly worn pads or you've other issues (suspension, caliper etc)

You need to have the car up in the air and the suspension checked over to see what may have failed/is failing (main culprits are thrust arms, track rod ends etc)

[RustyBitz]

Jesus this is a crazy thread revival