I've had a similar experience. After cracking my MY00 standard discs at Donington, I fitted a pair of direct replacement Bremsport plain discs. At first they were fine, but on my last track day they started to judder again - nothing too serious, but very annoying.

Now, on the road under normal braking they're just fine. As smooth as you like. But give them a good squeeze and the steering wheel starts to wobble again.

I can only conclude that when cold the discs are running true but when they get some heat in them and expand, they begin to warp.

I'll be asking Santa for some AP six-pots.

Hoppy

I've had the Subaru-fit Prodrive discs and pads fitted to my MY99 car, and they are doing a great job.

However, despite wearing them in gently for the first 500 miles, since about 1000 miles I have started to get a severe judder from them, but ONLY when they get hot. When driving at sensible speeds, they are as smooth as anything.

Any ideas?

This could be a sign that they are warped. It's common for brakes to feel fine, until they get hot, at which point the heat exagerates any defects.

You really need the dealer to drive the car, when the brakes are hot, as visual inspection won't show anything.

AP work to a max 4thou tolerance from true, and even 8thou gives shudder.

Mark.

See the post by DocJock on the 22B board. I agree with him.

Hoppy

PS I can't post on that board as I've forgotten my password and it's just been e-mailed to my office PC!

Hoppy, IMHO you are a man of exceedingly good judgement http://bbs.scoobynet.co.uk/wink.gif

DJ

As part of the natural process of use, the DS2000 material deposits itself on the disc face. As this happens more at high temperatures it is important to ensure that the pads are bedded in properly by gradually increasing the heat loading AFTER a proper period of pad bedding to the discs.
If the pads are not propely faced to the discs then the material is not evenly distributed around the disc. Also if the car is stationary whilst the disc is very hot or held using the footbrake at a junction or similar it is possible to deposit more material in one area of the disc. Subsequently this area of the disc has a different co-efficient of friction to the rest of the disc, particularly when hot and suddenly you have the appearance of a warped disc.
Two things can then happen.
1. If the car is driven normally for a period, ie the brakes never get particularly hot, then this area will be reincorporated into the whole disc and the vibration disapppears.
2. The car is driven very hard, the high friction area gets hotter and hotter and the disc warps.

Scenario 1 is normal use, scenario 2 is abuse.

Regards

Mike

[This message has been edited by MikeWood (edited 04 September 2000).]

As someone who has also experienced judder on the Prodrive disc upgrade, I'd like to know how you can recognise the onset of this potential damage, and what you can do to prevent it.

Any ideas much appreciated!

Greg

Thanks to everyone for your comments. Very interesting. Needless to say, I am bound to maintain that I haven't driven these discs anywhere near hard enough to justify the term Abuse, but I won't get drawn into the "Abuse vs Normal Use" argument because that seems to have been covered more than enough elsewhere http://bbs.scoobynet.co.uk/tongue.gif!

Greg, interested to hear that you suffered the same problem. Did your dealer replace the discs under warranty?

Mike B

>> Greg, interested to hear that you suffered the same problem. Did your dealer replace the discs under warranty?

Yes http://bbs.scoobynet.co.uk/smile.gif

[This message has been edited by gregh (edited 04 September 2000).]

Hey Mike - Be careful telling some of these boys that they may abuse their brakes - horses heads will be being deposited! http://bbs.scoobynet.co.uk/smile.gif

Well my replacement set performed flawlessly at Silverstone, including some heavy braking into the hairpin.

Fingers crossed the juddering in the last set won't be seen again!

Greg