Brake judder - bad!

andygb

After all the work which I had done on the Mondeo, I was looking forward to some nice, smooth stress free motoring.
However, in the last week, I have noticed a really bad judder (through the steering wheel), when braking from over 60MPH. It is a very bad judder/vibration, so yesterday I took the missus to work, and stripped down both pads and took the discs off. The discs and pads are only about eight months old, and have no real signs of wear, apart from slight corrosion around the edges.
I cleaned the hub/disc mating surfaces really well, applied slight amounts of copper grease to relevant parts, and put it all back together again, also making sure that the wheel/hub mating surfaces were spotlessly clean.
I took it for a test drive and,

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no different, no worse, still a very bad judder on any braking down to around 55MPH.
The tyres are not flat spotted (all good Pirellis), but anything like that would show up at high speed without braking.
Any suggestions folks, because this one has confused me. Could the discs have warped after ten thousand miles and eight months?

Andy

warehouse

Sounds like the discs are warped. This can be caused by the discs being seriously overtightened when fitted, (did you have problems getting them off?), or by severe heat on the discs, (sometimes caused by keeping the brake pedal pressed after heavy braking). Other causes could be rust spots on the discs if not used for a while, but from what you've said this can be discounted.

I've heard of cheap replacement discs warping early in their life, but never genuine ford discs.

andygb

You can't really over tighten these discs, because their design means that they are in effect being held in place by the road wheels.
Is there any way you can easily check if a disc is warped, some kind of gauge maybe?

harveybobbles

andygb wrote: »

Is there any way you can easily check if a disc is warped, some kind of gauge maybe?

Pop down to any MOT centre, they will put it on their rollers. Offer a crisp ten pound note perhaps.

kaya

warped discs or loose/worn suspension bushes, dont quick fit still offer a free checking service?

negg

Juddering can also be caused by the calipers if they are not on properly or worn or damaged.

Pew_Pew_Pew_Lasers!

There is no such thing as a warped disc. What can happen is that the braking surface of the disc becomes uneven, often due to a build-up of pad material.

If you have a spare car, I recommend finding the nearest half decent workshop with a lathe and getting them to skim a half mm or so from each surface of each disc.

warehouse

negg wrote: »

Juddering can also be caused by the calipers if they are not on properly or worn or damaged.

Or wishbones in extreme cases.

andygb

Pew_Pew_Pew_Lasers! wrote: »

There is no such thing as a warped disc. What can happen is that the braking surface of the disc becomes uneven, often due to a build-up of pad material.

If you have a spare car, I recommend finding the nearest half decent workshop with a lathe and getting them to skim a half mm or so from each surface of each disc.

I don't quite get this. The discs are revolving at extremely high speed, and the pads are made of a friction material which wears away gradually. If there was a build up of pad material, then the discs would turn black, and all discs which I have seen are either nice, bright shiny steel (like mine) or very rusty through lack of use.

mikey72

We've been here before recently

http://forums.moneysavingexpert.com/showthread.html?t=2012217&highlight=warped+disks

(if you machine 1mm off the discs at the front of my car, that's about half the wear they're allowed gone in one go)

onejontwo

Treat yourself to some genuine ford discs and pads, that way if the problem reoccurs in the next 10,000 miles you're covered by fords warranty.