ZX front brake rotors

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Posts: 195
Joined: 18 Apr 2001, 02:09
My Cars:

ZX front brake rotors

Post by Dave1 » 03 Jun 2002, 02:26

On the subject of brakes I have a question. When I aquired my Volcane TD the front discs were worn and braking was a series of judders. I replaced the discs and pads with Mintex equipment. For a while (6 months) things were fine but gradually the judderding came back until eventually after a couple of years and maybe 15K miles braking at speed was risky. The discs were not warped but had a series of scores running from the outer edge to the centre on the inner side of the discs(the side next to the cylinder)on both off and nearside. It seemed these caused the juddering. I changed again for Ferodo and all ok but 11 months later the first sign of uneven braking appeared pulling slowly to a halt after any heat had been generated. This time I have complained and got the discs changed by Ferodo. The same score lines and pitting was forming on the inside. I know ZX brakes are not the best but does anyone know if it is purely heat that causes the scoring. I have been extra careful with the last discs as well. All obvious things like seating on the hub have been double checked. Is it just that the discs are not up to it it? I understand they are all pretty much made by the same company whatever the name on them.

Dave Burns
Posts: 1916
Joined: 14 May 2001, 05:30
Location: United Kingdom
My Cars:

Post by Dave Burns » 03 Jun 2002, 21:21

Scoring on the inner face of the disc is more common than on the outer with front disc brakes, I suspect this is because of the crap that get's thrown against them as the opposit wheel goes through water, resulting in bit's of grit getting between the disc and the pad.
Car's of yesteryear had splash plates on the front's, now you only see them on the rears where disc brakes are concerned.
On my Xantia the scoring on the rears is the opposit way round, gone bad on the outer face and very smooth and even on the inner face, this must be because of the splash plates on the rears, they run fairly close to the disc so nothing can get at them.
I don't quite see how these grooves could cause juddering though, for this state to arise you either need a warped disc or a disc that varies in thickness as it revolves.
If you have a dial test indicator use it to clock the disc on both faces, this should tell you whats going on.
When you fit new disc's they should be clocked with the wheel bolt's in place and tight, with spacers if needed to ensure the runout does not exceed the maximum specified.
The quality of machining now days is such that bad disc's rarely make an appearance.