330i - annoying brake judder

[Laird 'o Croft]

Brake judder question.
BMW E46 330ci Sport.
Serious brake judder on trackdays but not with regular on road driving,
Done the discs and pads - its still the same.
Done the alloy control arms with ball joints and bushes - its still the same.
Put a pair of brand new calipers on - its still the same.
New set of wheels and tyres - its still the same.
Now I'm baffled!!

Regards
Nick

[andyiley]

Remove the discs, ensure the front surface of the hub, and the rear surface of the disc is 100% clean of ANY debris/rust/much/grit etc before re-fitting.

[mark.c]

Sounds like a bit of pad transfer. Did you bed the brakes in after you fitted them?

[Laird 'o Croft]

both good points, thank you.
mating surfaces are as clean as a whistle, wheel to disc and disc to hub. pads have been bedded in sensibly and heat cycled as well.
I have been trackdaying road going E30's and E36's regularly for 25 years and never had a brake judder I couldn't sort easily.

My next step is to have a look at the ABS

Nick

[mark.c]

another though...What about a sticky caliper that doesnt like getting trackday hot? Maybe after a cool down lap you might feel one wheel hotter than the other?