Brakes advice

[PenguinGTI]

I've posted this in the mk6 section and the Trackdays section. I don't know where is more appropriate so Mods please correct me if I've made a mistake.

Right, I've noticed when the brakes are warm and I brake hard there is a thum-thum-thum comes from the brakes and the steering wheel seems to vibrate/wobble. It occurs pretty much only when I am really pushing it.

Could someone advise me what they think might be wrong. Is it a case of a warped disc or could it be pads?

My tyres are also getting low so could it be a wheel balance issue? The symptoms don't appear during normal driving and braking.

I don't have much experience in this area so all advice is appreciated.

[Diamond Hell]

Isn't it still under warrantee?

Swap the wheels front to back to eliminate whether it's wheel/tyre based or brakes.

I don't think it'll be brakes, especially if your front tyres are nearly shot away.

[PenguinGTI]

Thanks for the reply DH, I've got this up in the mk6 section also. Kenny in there reckons its down to the discs not dissipating the heat very well.

Here's some more information. The first time it happened was on the Ring. I was coming into the Adenau section and the steering started shuddering under braking. Quite disconcerting. I also felt like I had no stopping power (I assume this is just fade). So I immediately backed off and took it easy with the hazard lights on for the rest of the lap.

Upon returning to the UK I got it into the workshop for a look.

As for warranty I spoke to the workshop manager the last time this happened. It was he who advised me originally that it sounded like a warped disc. We discussed whether the warranty would cover it and he said that as brake discs are consumables and I had covered 24k miles on them then the warranty would no longer cover those components. Based on that I got them replaced for fresh OEM discs.

I have since covered a further 12k miles on these fresh discs. The problem did stop once I had replaced the discs which leads me to believe it is the same thing but it seems strange that it is returning after 12k miles.

I was hoping to eliminate what is not at fault. My understanding is that wheel balance would affect general driving regardless of braking force or brake temperature. For example there would be vibration cruising at 70mph. Therefore, while the wheels may be out of balance, I do not think they are the cause of this problem.

If it is simply a warped disc then I suppose it is simple enough to sort but nonetheless disappointing in the short lifespan of the disc I had.

Could there be anything else involved. I take it is not linked to suspension or anything?

[Diamond Hell]

Sounds like it might well be your pads 'going off'.

If they get *really* hot the pad material can release gas, which can effectively 'float' the pad off the rotor.  Grooved/drilled disks are part of people trying to resolve this issue.

To me this is addressing the symptom, not the cause.  If this is a consistent problem for you (and it sounds like you're knocking on for Hurdy lap-times if you're over-heating the brakes!) then you need to look at uprated pads, or bigger front brakes, to increase the gripped area.

Good luck with it and let us know how you get on.

[PenguinGTI]

Right, well took the car into the workshop just there and one of the technicians came out with me. We both had a go driving the car and he agreed that something was up. He couldn't say if it was a warped disc but said the disc definitely needed closer inspection. Booked in for tomorrow afternoon. 
 

To me this is addressing the symptom, not the cause.  If this is a consistent problem for you (and it sounds like you're knocking on for Hurdy lap-times if you're over-heating the brakes!) then you need to look at uprated pads, or bigger front brakes, to increase the gripped area.

I am considering this.

[PenguinGTI]

2 Front Discs replaced under warranty 

[alexd]

See if you can find a set of cheap drilled + grooved to test if they still get like this, tbh i would say your just using them a lot quicker than they are meant to be, they would probably last 100k if frank and dorris were using it for every day use. I used to do a set of brakes a month in my Civic, all depends on how you drive your car, sounds like your driving it properly  Just sounds like you don't wanna pay to maintain the fun 

[danny_p]

there is a simpel solution,   when you ragging the nuts off the car don't park it up straight away,  back off a mile or two before the end of your journy to allow various patrs to cool down,   as if your disk are roasting hot when you stop the pads insulate the disk causeing that part of the disk to cool more slowly,  when there really hot this can affect the propoties of the metal the disk is actualy made of rather a lot,  all disks are suseptabe to this bar the carbon ceramics