brake judder.. help please!

[Lankstarr]

My car had a full set of discs at 40k.

When I got it at 44k it had a slight judder whilst breaking and now it is getting much worse. It seems to be coming from the front left but the disc is still almost new. I thought about replacing the front discs (thanx for your help with the info Simon) but this seems crazy now as if one has warped already then it is sure to go the same way if it is replaced.

I think I can get the disc skimmed if it is warped but if there is something else causing the disc to warp then I need to tackle at source.

If the disc is not warped then I don't know what it could be.

Does anyone have any

alternative theoretical diagnoses
possible theories on what may be causing a disc to warp after so few miles



thanks for your help

L*

[simonprelude]

I have a full set of discs (used) that you can borrow. To check against, it could be the disc, the hub surface may have grime on it, or it could be the calipers.

Best bet would be to run a CDI (clock dial indicator) against the disc whilst the car is jacked up. Don't suppose you fancy going to the rolling road via mine on Friday night as well then we could try and sort it out ??
Matt is staying over as well.

[blue5]

I have found that brake judder usually has few causes

Either a warped disc, a bent stub axle or a sticking piston

Take the wheel off and rotate the disc holding a piece of wire against the disc, resting it on the caliper.

As the disc rotates you are looking for any variation in distance from the tip of the wire to the disc as it rotates.

Obviously a DTI is the correct tool but the wire will give you a visual.

If you have been driving hard it is possible you have warped a disc.

Alternately chect the bolts which hold the dics on, give the disc a good shaking with both hands every 25deg of rotation or so to see if there is any movement.

Finally put the wheel on again and whilst still suspended from the ground do the wire test on the rim to see if there is any deflection.

You might have bumped over somthing

Hope this helps

[Lankstarr]

Thanks guys.

Can't make it out to play on Friday night Simon but thanks very much for the offer. I am free all day Saturday and making the early run up with Paul and Paul so maybe we could do something on Sat?

If not I have some points here that I can get going with so that should keep me busy. If could could bring your used discs for me to try out that would be great, it might help me eliminate other problems before I fork out for a new set.

Many thanks

L*