Dodgy Discs

[Ice White Socks 0]

Hello,

 

When I pull up to a junction braking gently, the brakes grab on and off slightly which feels like warped discs :( . Which ones are more likely to have warped- the fronts or backs? How much is it going to cost me for an upgraded set of discs/ pads- also do people every upgrade the rears as well or are stanadards more then capable?

 

Cheers

 

Mike

[Henny 0]

If you've warped the rear disks, you've REALLY over done something at sometime! :shock: Much more likely to be the front disks that are causing the braking vibrations... :?

 

The front brakes do most of the braking anyway (around 80% IIRC) so it's these that are the ones that you need to think about upgrading if you want to go down that route... 8)

 

The standard rears are more than capable of locking up the tyres if you adjust the compensator valve (which is what it's there to prevent! ;) ) Most people who upgrade the rear brakes only do it for visual impact... anyone who says otherwise either likes to be able to throw the rear end out while it's locked up, or doesn't really know what they're on about. ;) :lol:

[Mike Edwards 0]

Warped disks cause vibration that feels like an unbalanced wheel when braking gently from speed.

 

Grabby brakes is something else...

[Supercharged 2]

Sounds like seized pistons - when was the last fluid change?

[Ice White Socks 0]

Fluid was changed only a few months back :? . Surely if the brake are applied say 20%, then the grabbing occurs when the warped part of the discs moves into and out of the pad as it goes round. I don't suffer any other braking problems save epic amounts of fade on mega thrashes :-P - but I know the discs and pads are shagged anyway because it went in for a new wheel bearing today and the garage flagged up the worn pads and discs in that other comments part of the receipt.

 

I am not disregarding your comments though- I'll get the discs/pads sorted out and if there are still problems I'll have a look at the pistons/calipers.

 

Cheers

[Kevin Bacon 5]

Definitley warpage at the front. What sort of wear ridge do you have on the fronts? The disc's ability to dissipate heat diminishes with wear. Warping is more pronounced with a light pedal pedal press.

 

When waiting at the lights, do you hold the car with the footbrake or the handbrake? The former method causes localised cooling via the pads, which is the main cause of warping.......that and not bedding them in sufficiently.

 

K

[biggrim 0]

I also hear that if you don't clean the mounting surface at a disc change it can cause the same effect as a warped disc as the disc will not be 100% flush with the mounting surface. When I bought my G60 it had a similar feel to the way you describe and it turned out to be my Greenstuff pads retaining heat and sticking to the disc when stopped at lights and leaving debris on the disc. £200 later and everything was sorted 8) HTH