Warped Discs

[TommyTT]

My Girlfriend drives a 2007 XJ diesel with 15000 miles. She is now on her third set of brake discs in little over 3 months. The original set were replaced at 10000 miles because of a judder under braking, the next set lasted about 3000 miles before the juddering got really bad and now some 2000 miles later the third set are starting to go as well. All the work has been carried out under warranty at a Jag dealer, but it seems pointless to keep replacing discs if the problem is going to reappear. Any ideas?

[GreenV8S]

http://www.stoptech.com/tech_info/wp_warped_braked...

[Tame Technician]

Is she riding the brakes all the time or something?? or driving like me and over heating them??

If not I would suggest its the front hubs that are distorted and advise the dealer to replace the front wheel bearing/hub assembly too, next time the discs are discs get done.

[ultegra]

Green V8S is prob right - you don't actually have warped brake disks unless you have measured with a DTI them and determined they are running out of true. Much more likely to be surface contamination / picking up with rubbish pad material. Suggest switch to EBC redstuff or equivalent. Need to decontaminate the discs first, mind you - garnet paper treatment etc.

[Jaguar steve]

Discs will warp.

If you get them up to a high temperature during a fast drive and then hold the car stationary - as most people do if it's an auto - on the brakes then you will get localised overheating where the pads are in contact with the disc. In an extreme case this gives a temperature imbalance of hundreds of degrees on the disc which is more than enough to warp it.

Im my experience cleaning discs to get rid of contamination and glaze is usually worth a try, especially if it's your money you are spending but more often than not steering judder and feedback through the brake pedal suggests it's time for some new discs and pads.

[Grady]

Just my 2 cents - haven't experied this with Jags but in other heavy vehicles (SUVs), that pulsing feeling known as "warpped rotor" is banished by switching to drilled rotors and the habit of releasing the brakes after a hard stop.