Brake judder - bad!

DaveMacD

You used to be able to pick up a gauge to check run out on the discs, but I'm not sure how much they cost. I suppose it would be possible to bodge up some form or method to check if the discs are out of true...

andygb

onejontwo wrote: »

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.

I have been quoted £65 each for just the OE discs - that is a lot of money. I will scout around for other prices on quality parts.

andygb

DaveMacD wrote: »

You used to be able to pick up a gauge to check run out on the discs, but I'm not sure how much they cost. I suppose it would be possible to bodge up some form or method to check if the discs are out of true...

Weather permitting, I will get the wheels off tomorrow, and rig up a kind of pointer attached to the strut, then revolve the disc slowly, to see if there is any movement up or down, in or out against the pointer. If everything is true then I am - confused!
There is absolutely no vibration of any kind on the motorway, except when you even feather the brake pedal between 55 - 70MPH.
Cars - don't you love them?:mad:

mikey72

Have you tried swopping the tyres side to side, or even front to back?

Pew_Pew_Pew_Lasers!

andygb wrote: »

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.

They're not revolving at high speed when they're hot and stopped, and when the pads are still pushed against the braking surface. Then, when they're next used, the part of the disc that was held by the pad is worn less than the remainder of the disc which wasn't. Hence, uneven wear.

andygb

mikey72 wrote: »

Have you tried swopping the tyres side to side, or even front to back?

The tyres are almost new (less than four thousand miles each) and I had the balancing checked just before Christmas.
I have had recent work done on the car - new drive shaft, wheel bearing on the offside, coil springs in the last six months.
This problem has just appeared since the Christmas break.

thescouselander

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.

Yes, listen to pew pew - he speaks the truth!

AdrianHi

Here is the article I came across a few years ago on another motoring forum that explains why brakes disks do not warp, what the real cause is (pad material build up in one location as described earlier in this thread) and why it can - and you can even expect it to happen to new disks and pads if you don't bed them in properly.
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
It never gets hot enough even in extreme motor racing for disks to get warped.

My previous car had to have the disks scimmed about once every 20,000 miles for the fiorst 60,000 miles (3 times in total) and then the problem never reoccurred. I sold the car at 122,000 miles still with the original brake disks on.

onejontwo

Whether they be "warped", "Pad build up" or whatever you will still need the discs skimming which would probably put them past their minimum thickness and cost a few bob, or as I said earlier get genuine ford discs and have the benefit of the warranty as we sent many hundreds of discs back and one of the questions as to the problem on the warranty return sheet was A.....CRACKED DISCS
B.....WARPED DISCS .