Brakes juddering

Since fitting the APs on the fronts I've noticed a judder when I brake at high speeds... basically it's whenever I brake at over 50mph but as soon as I drop below that the juddering stops... any ideas what the cause could be or is this normal on APs? :confused:

Yves Adele Harlow;2689 wrote: Since fitting the APs on the fronts I've noticed a judder when I brake at high speeds... basically it's whenever I brake at over 50mph but as soon as I drop below that the juddering stops... any ideas what the cause could be or is this normal on APs? :confused:

I have AP's but they are fine at high speed.

slightly warped disc?? :dunno:

loose pad?? :dunno:

Yves Adele Harlow;2689 wrote: Since fitting the APs on the fronts I've noticed a judder when I brake at high speeds... basically it's whenever I brake at over 50mph but as soon as I drop below that the juddering stops... any ideas what the cause could be or is this normal on APs? :confused:

I also have AP`s, no problems at any speed. I think you should get this sorted pronto even by a professional. Brake problems, even minor ones, can be highly dangerous.
Just wondered is this associated with that flapping noise you posted a while ago ?

A brake judder would indicate a warped disc or perhaps the disc not sitting square onto the hub - did you take the discs off golden wheels and did you use new pads? Also is the disc surface smooth or is it grooved a bit (run you finger nail over it to check)

I was going to ask if you checked the brake run out. If the disc isn't sitting squarely on the hub it will cause this. Might be an idea to reseat the disc and check that the surfaces are clean. Any little bits of rust etc between the hub and the disc will cause it to sit wonky.

I fitted GW discs & pads to the front as well. What was interesting is that we noticed one of the pads had slightly uneven wear on it where it looked like every time it had gone round a certain part of the disc it hadn't gripped properly. However there was no sign of anything wrong with the disc so we just ignored this.

Thanks David.

Well we jacked up GS1 today, rotated the wheel and thats definitely the cause of our fluttering sound. It's coming from both front wheels. Took the wheels of and span the discs - definitely doesn't sound right. Have recoded the sound so am currently uploading it to You Tube - will post vid when it's been uploaded. Cleaned the discs but that didn't make a difference. My best guess is the disc is rubbing unevenly against the pad. Anyway will post vid shortly...

Video now uploaded!

[ame=http://www.youtube.com/watch?v=GYJ9P4UVvIY]YouTube- Brake discs rubbing on AP Calipers[/ame]

Take the discs off and see if there is anything stuck under the mating face, such as rust etc.

If you can find an engineering workshop you could ask them to check them for warp too. If they are warped you should be able to get tem skimmed for not much money if they aren't too bad.

CJJ;2785 wrote: Take the discs off and see if there is anything stuck under the mating face, such as rust etc.

If you can find an engineering workshop you could ask them to check them for warp too. If they are warped you should be able to get tem skimmed for not much money if they aren't too bad.

Ok... will check for rust & give it a brush down with a wire brush.

Also I should mention that the screws that hold the discs in place aren't there (well one of them has one on) so don't know if that could make a difference? I gave them a wobble and they felt pretty secure.

Am I right in thinking they shouldn't sound like that though?

Yves Adele Harlow;2801 wrote: Am I right in thinking they shouldn't sound like that though?

They should run freely with no noise. It isn't uncommon for brakes to sound like this and really doesn't normally cause a problem unless the uneveness effects the braking.

They are either slightly warped or they are not on square.