Warped disks

[viceroy]

How do I know for sure if I have warped disks?

During light breaking at low speed, there is a kind of increase and decrease in breaking even though my foot is steady on the brake pedal.

 

[KDF]

Juddering on breaking hard at high speeds is usually a good sign...

 

[alnug]

yes i agree on the juddering of the brake pedal/ vibration of steering at high speeds BUT...i wont really say its a GOOD sign lol

 

[viceroy]

nope, non of that, just a kinda increase and decrease of braking at low speed with my foot steady on the brake pedal.

The breaking is actually very smooth at high speed hard braking

 

[KDF]

by good sign, i of course meant a good sign that you have warped disks.

the only thing i can think of is the ABS causing it, but there is a very slim chance of that happening.

 

[RobFenn]

juddering is caused by ABS but more likely, the EBD. This however wont cut in unless your foot is pressing down hard, and for a long time, which means youll be skidding. You should be able to eliminate the ABS thing as you can feel it working.

What mileage is your car on, and has it ever been used on track? I wouldnt expect your discs to be warped, but if they are, it would be worthwile investing in some better ones! Thing is if theyre warped theyd be even worse at highspeed breaking.

Id get it looked at

 

[viceroy]

Well its not juddering, Ive had cars with disks that needed to be skimmed and this was nothing as juddery as that.

More like a gentle increasing and decreasing of braking at low speeds.

Anyway Ill take it to ranult next week and ask

 

[alnug]

yeah...sound like you know your mechanicals...so if youre not sure..best bet would be to take it in to Renault and see......its not brakes not warmed up is it? Does it do it after youve been driving around a while?...maybe my best guess would be that they will say you have glazed pads....

 

[viceroy]

nope, seems to happen any time, whether brakes are warm or not.

Will see what they say

 

[BenR]

waped discs will almost certainly be a vibration/judder from the pedal......if its ABS then the car will jerk whilst the wheels lock and unlock.

 

[konahead]

yep yep...i know mine were warped and they had the same juddering feel thru the brake pedal and was definitely not ABS...now that ive change the discs...aint no juddering anymore...

 

[KDF]

It could be something to do with the pumps that assist you when you break, they are in a split diagonal formation, maybe one of these is faulty cause the pulsing feeling ?

Other than the ABS thats the only thing directly connected to the braking system that I can think off. (master cylinder, but I doubt that)

 

[BenR]

i doubt it will be anythign with the pumps as there is only the ABS pump, then your master cylinder.

and nothing in the braking dept. will cause judder except waped discs....

take off your wheel, spin it and look for run out.

 

[Eddd]

If you have used the car hard you may have deposited brake pad material on the disc. This feels just like a warped disc. Try to get some heat into the brakes and see if you can get things to smooth out. A few good hard stops or left foot brakine whilst cruising along and you may just fix the problem.

Then you want to drive until everything cools down before stopping.

Ive often reconditioned the discs in this manner after a hard day at the track.

 

[BenR]

hmmmmmmm.....

large amounts of breake pad material left on the discs are only really there if you have them baking hot, then sit on the brakes say in the paddock. i.e. dont leave the handbrake on.

If this did happen its quite obvious...........

It would be far easier just to take it as warped discs......which is an easy thing to do.

Besides, new discs are only about 45 quid a set of fronts.

 

[Will16V]

Think ud better check ur pads, i noticed this on mine before i changed the pads - the drivers side was down to the metal backing! only at slow speeds tho, when stuck in traffic n stuff..