Brake Problems - 996 TT

I am experiencing vibration under braking on my 2001 996 TT. The vibration is coming back through the steering wheel and causing the steering wheel to saw or judder, left and right to a degree It happens at around 50 down to 30 MPH. Have recently had new discs and pads on the car. Following this, the symptoms weren't present, but now, a 1000 miles after the new discs were fitted, I'm back to square 1. Also, the wheels were replaced at the same time as the new discs and pads were fitted, so I don't think wheel ballance is an issue. I suspect a brake imbalance. Maybe caused by a sticking piston. I haven't noticed any brake fluid leaks or drop in fluid levels, so doubt a ruptured seal. Any thoughts on the likely cause of my woes? All advice gratefully accepted.

Could be pad build up on the discs, did you bed them in properly? Try some very heavy braking from high speed to see if you can shift it, you'll need to do it quite a few times. Also are the holes in the discs clear or are they filled with pad material, again you need to keep these clear.

It is so easy to wreck your brakes-I never brake then leave my foot on the brakes when I am at a standstill. At best it deposits the pads on the disc as above, at worst the heat warps the discs. The second you come to a halt foot off the brakes. Sorry if I amteaching you to suck eggs but I had to have it drilled into me. This is why autos go through brakes like nobodys business-people sit at lights etc with their foot on the brakes...knock it into neutral to stop the creeping forwards.

I'm quite shocked that I never knew or thought of that before... and I have a degree in Automotive Engineering! Thanks for that tip - could explain why I have a brake judder on my Sprintshift (semi-auto) Camper-van :shock:

i have slight steering wheel judder on the TT when braking heavily from speed - which Paragon puts down to slightly warped discs. Apparently this is a common problem with the 993 - not sure what the situation is with the 996. My discs look visibly quite recent replacments, so apparently not an age / miles thing. cheers tim

Its something to do with the heat disipating (sp). The disc cools down much slower where the pads are clamped onto the disc than around the rest of it therefore warping occurs...I think!

Absolutely 100% makes sense - and the more efficient the discs are at cooling (eg ventilated and cross-drilled on our cars) the more heat difference there will be across the disc - and therefore more likely to warp! It's been one of those "Doh" moments for me, and probably explains the 3-4 sets of warped discs I've had to replace in my 7 years of 911 ownership! And I thought I was one of the most mechanically sympathetic drivers I know - I never use full throttle, or more than 3500 revs, before the engine's warm, and heel and toe every downchange for Christs sake!!! :shock: :shock: :shock: I shall now mostly be taking my foot of the brakes when stationary!

I agree with you Wattie.

In a similar vein if you have been giving it some beans and got the brakes very hot - if you can avoid it don't park up with the handbrake on. That can contribute to warping the discs also. If possible leave in gear on the flat. Those temperatures should only really be being reached on the track though :wink:

I came across someone recently who had new discs and pads fitted at an OPC and was experiencing brake judder at 70 down to 40. After I suggested he checked the torque on his wheel bolts the problem was gone. It's always worth checking the simple things first.

I really doubt you've warped your discs, so unless you've got smoke bellowing out of your arches and discs that are as red as a baboon arse I'd disregard that. It more likely to be pad deposits from incorrect cooling down ie. lack of it, leaving handbrake on etc etc

I know this is a bit off topic and I do leave my handbrake off while the car cools down but.... how can leaving the handbrake on warp the discs, when it's operating shoes inside the disc hub and not applying the pads to the disc surface :?:

Thanks guys for your thoughts and advice. I seriously doubt that the discs are warped. However, I will check the run out this weekend with a DTI and see what comes up. I will be doing all the aforementioned checks and inspections, with regard to torque, debris build up and cleanliness. Hopefully, will be able to report an improvement next week. Thanks again. Code:

The first reply about heavy braking works a treat. It makes a huge difference if you stamp on the brakes hard from well over 100 to 30 five or 6 times in a row. I find those bypasses excellent for this. Up to 150 then slow for the round about and the same on the next stretch of dual carrigeway. After 5 or 6 times the brakes smell great and work very well. Dont forget to drive steady for a while after to cool it all down!

OK folks - finally got to the bottom of this. It turns of that the OPC screwed up the fitting of front wheel bearings in June 2007. I would have thought a pretty basic task, but hey - everyone has a bad day. The up shot of this is that I have had 2 sets of discs fitted to my car since June. 1 set by an indy (who mis diagonosed the fault) and 1 by an OPC who also mis diagnosed the fault. The car went back to the OPC at the start of December, where they finally conceded that there was a fundamental issue/fault with the fitting of the bearings. A fair bit of negotiating resulted in my money being refunded, a good will gesture in the sum of £200 and a nice bottle of bubbly on the front seat when the car was delivered home. Plus the car was back at status quo: new bearings, hubs and discs sorted. So, the moral is, stick to your guns if you believe you are right. Even the OPC's make basic mistakes!