Warped discs - definitely calipers?

It seems to me that some discs are prone to warping you leave your foot on the brake after braking, which causes the discs to cool down more quickly away from the pad than under it. I don't know why this sometimes happens and sometimes not.

Rob Graham

Did you check the runout on the new disks after you fitted them?

I learned, the hard way, that there can sometimes be a quite a lot of runout still there after changing the pads. It won't be noticeable as brake judder, but it will make the new disks wear unevenly until the judder comes back big-time.

Dial gauges are quite cheap now, and they're a really good investment.

Colin.

Are you _sure_ it's warped discs?

I had a Mk2 that had issues with the slider pins on the calipers seizing, leading to the caliper being at a slight angle that gave exactly this symptom.

Stripping them down & a re-grease solved it.

Pete.

Also if the suspension bushes have gone soft it makes an y runout much more noticeable at the wheel

This is apparently the most common cause of recurring judder. There's a good article about it somewhere - I'll see if I can find it. Anyway, it usually means the caliper needs stripping and regreasing or replacing. Fitting new disks rarely sorts it out long term, unless the fitter happens to clean up and regrease the calipers at the same time.

Al

You're lucky to get the car back with its wheel nuts tightened up these days, let alone cleaned up and greased the callipers!

Regards tox

Apart from the maintenance stuff of lubricating the caliper slides and bleeding the brake fluid, I found that jumping on the brake pedal periodically (while the car is stationary!) seems to free the movement of the calipers.