xantia brake judder

brookdale31 · Post by **brookdale31** » 20 Oct 2004, 14:08

Can anyone help me. I have recently bought a 1995 Xantia 1.9TD. There is a judder on the brakes as the vehicle comes to a stop. It appears to be coming from the nearside front. I have put new pads in,swapped both calipers as one was leaking and put on a new nearside drop link as the ball joints were worn. This has still not cured the problem. There is a knocking noise, which i presume is one of the anti roll bar bushes. Could this be causing the judder? I can only feel it through the pedal, it does not effect the streering. I have considered warped discs but a feeler guage check on both sides doesn't show anything up. Is this a common problem?
Eamonn

franciscomurat · Post by **franciscomurat** » 20 Oct 2004, 21:19

hi,recently changed all 4 discs because of brake judder.... that did the trick despite many people saying other things,not alot of money considering the final satisfactory result...try it.

AndersDK · Post by **AndersDK** » 20 Oct 2004, 22:26

Hot spots on the discs can do this.
Greasy spots (even fingerprints) on brake discs burns out to give a different abrasive surface in spots - causing judder.

Kowalski · Post by **Kowalski** » 20 Oct 2004, 22:30

Judder doesn't just mean the discs are out of flat, it means the discs have more runout than the calipers can cope with.
I've had new discs go onto a Xantia and had judder, even though the discs were within tolerance. The front calipers on a Xantia are a single piston floating caliper. If the main slide pin gets dry (i.e. not well oiled/greased) the caliper can't slide freely and you get judder. If you are replacing discs / pads this pin should (in my experience) be greased every time.

Dave Burns · Post by **Dave Burns** » 21 Oct 2004, 04:09

Maximum specified disc run out is only a few thou anyway, if the disc is trying to tug the caliper from side to side by more than that tiny amount its way out of tollerance, but the slide pin isn't the real problem, because to move the caliper on the pin the pads have to also move on their slides, and when the spring is bearing down on them they don't move very easily at all.
Feedback at the pedal is also commonly caused by discs of differing thickness due to uneven wear, feelers aren't really good enough for this purpose, you need a dial test indicator for accurate measurement.
Dave