Probably a daft question but...

[tezza77]

I trust that if I am boiling the brake fluid in my 996 turbo then stock pads are no good to me either?

A few good laps at knockhill and I'm boiling so just replaced with Castrol SRF but also, I have a violent wobble under braking when the brakes are hot, it shakes the whole car, its nasty. I have changed discs and pads with stock parts, would overworked stock pads exhibit this behaviour?

[Hilux2400]

Severe wobble under braking is often caused by a misaligned disc. As it revolves it wants to change the location of the pads.

The new disc might have warped or it might not be seated properly on its mounting face.

Check the run out on a lathe bed.

[mollytherocker]

You must be very heavy on your brakes. Are you doing a cool down lap?

[RatBoy M3CSL]

..Check the run out of the discs on the car first of all, if they are fooked, that's your answer,

If they run true it's most likely pad deposit on the discs when they get hot, Ferodo DS 2500's were notorious for this, when they get hot some of the bonding agent overheats and comes to the surface of the pad which smears it all over the discs grabbing the pad and it rattles the steering it happened to me and when I clocked up my discs which were fine so I went with RS29's and sorted..

If your whole car is shaking when you brake it's more likely a buckled disc(s), or 1 is mounted on grit and not running true.. but it's an easy fix.

Always do half a lap cooling down before you come in, never spank it to the last corner then come in and park it, that's when your brakes buckle, and never use the handbrake either, just drop it into a gear as a brake..!

Edited by RatBoy M3CSL on Saturday 20th July 09:19

[Far Cough]

It could just be pad deposits on the disc causing the grabbing when hot. It sounds like you have overstretched the oem kit and this may cause the pad to effectively melt and leave a residue on the rotor. Did you stop in the pits and keep your foot on the brake ? as thats all it can take.

Get a more aggressive pad to match the fluid upgrade and this will most likely clean off the pad deposits too. If not then you need to be looking at the rotor itself as others have mentioned.

[_gez_]

And get some 997 turbo brake ducts (officially known as a spoilers) that clip on the lower wishbone. Quite a bit bigger and cheap.

[tezza77]

Thanks for all the advice. With the SRF in it was flawless at knockhill yesterday so the new pads and fluid change have hopefully sorted the problem, if not I will have a go at some of the things mentioned

[Rockster]

tezza77 said:

Thanks for all the advice. With the SRF in it was flawless at knockhill yesterday so the new pads and fluid change have hopefully sorted the problem, if not I will have a go at some of the things mentioned

This suggests the wobble was the fluid boiling in the calipers and acting as a vapor activated ABS which was causing the brakes to pulse or wobble.

BTW, I can't ever recall coming upon posts by other Turbo owners reporting boiling the brake fluid. I would hazard a guess you are misusing the brakes and overheating them severely because of this.

Dare I suggest you need to evaluate your braking technique?

[fioran0]

Knockhill is horrendous on brakes (and in general). Its a motorbike circuit fundamentally.
The combination of 3500lbs heavyweight and piddly brake spec mean that a turbo is going to experience it worse than most on there.
SRF is a band aid to the issue though may suffice just fine depending on how often the OP is intending to go out.