Help! Brake judder problem.

[Twinpipe]

A while ago I noticed a bit of judder coming through the steering under moderate braking.
I put some new pads on all around and then did a track day where it became infinitely worse, almost to the point of undrivable!
I changed the front discs and the judder went.
About a thousand miles in and it started to come back. (I'd driven to the Alps by this point)
Two thousand miles in and its getting worse again.
There is excessive dust build up on the front left wheel.
The car pulls left a little. (may not be related, haven't checked the geo)


My theory is that one of the pads is sticking a bit and causing the discs to over heat and warp.

Do discs warp that easily??

Would I get any judder just from a sticking pad??

Could it be a problem with the rubber brake hose?


I had a look at the calliper and all the pistons do move albeit one of the four is a little lazy.


Thanks for your input guys.

[andyiley]

The same as with any diagnosis, my first advice is always tackle known problems first.

Yes it is possible it could be the cause.

You found the problem originally & the same sounds like the problem again.

You just need to find the cause.

If you do end up changing the discs again ensure they are cleaned before fitting to remove the oil and also ensure the hub & disc faces are fastidiously cleaned of any dust & debris to make sure they seat perfectly flat & true.

[lanan]

Twinpipe said:

Do discs warp ??

No.
It is usually pad material transferred unevenly on the surface of the disc giving that feeling.
Often caused by the car sitting stationary after a big braking session

[andyiley]

lanan said:

Twinpipe said:

Do discs warp ??

Discs CAN warp, but it is not very common. It is far more common for judder to be caused by dirt/rust/debris in between disc/hub.

[VinceFox]

I've had an ongoing thing with my m3 that was similar.

Popular one that people miss is sticking/slow returning pistons or sliders. A less commonly spotted one is an internally collapsed brake hose.