HELP with potential brake problems..

[Martin.]

On the last session on my last trackday my brakes felt really odd. Under high-ish load they were making the whole car really judder. At first I actually thought I had a flat tyre, that's what it felt like. It was really off putting.

So naturally I stopped and had a little inspection to see if anything looked odd. All seemed fine, but I'm no mechanic. I assumed they were just far too hot from the full days hard driving, and called it a day.

Got my mechanic to give them a quick once over a couple of days later. Apparently all fine so I forgot about it.

Did another trackday this weekend. My first session of the day, as I was late arriving. Did a few warm up laps. Then started to progressively push on a bit harder. Until the brake problem popped up again. Under medium to high braking the car completely judders/shakes. It's really off putting and really knocked my confidence in the car.

I did a few slower laps and was trying to distinguish if it was one corner in particular but I couldn't figure it out. (only managed about 8 in total before the day was cancelled due to someone crashing). Now I'm assuming something has got to be wrong, but I can't or at least I don't think I can replicate the same shuddering on normal roads. The brakes seem to be fine on road driving...

I will obviously hand the car back to my mechanic and explain it to him, but I thought maybe one of the experts on here might be able to tell me what it could be or a few things which need to be checked. Basically I want to try and narrow it down. Hoping it could be something simple like a fluid change but I have no idea...

Any help or advice will be much appreciated.

Cheers

 

[easym5]

Its usually a sign that the disc is warped,they get worse the hotter they get

 

[Martin.]

Really.. hmmm ok thanks I'll bare that in mind. I did check them, but to see if they were lipped. Would I have not noticed if they were warped? Or if not me, at least my mechanic?? Or is it easy to miss?

 

[Martin.]

Also what's the main cause or warping then? Haven't had them on long...

 

[Martin.]

Anyone else got any ideas for me?

 

[Chip-mk1]

Warping sounds very likely to me.

Heat causes the disk to go slightly out of true, its not enough that you would notice it unless you spun it up on a lathe though.

Other possibility is that something is moving that shouldnt, so for example a worn wheel bearing, but I would expect other symtoms then, like a droning when cornering or similar.


What disks are they?

The Brembo HC ones are pretty good and are cheap
http://www.kamracing.co.uk/renault/...iscs-renault-clio-mk2-rs-172-182-2-0-16v.html


What pads do you use?
DS2500 or Pagid Blues are both highly regarded on these cars/

We have pagids and brembo HC on our ph1 turbo, and ds2500 and brembo HC on our RS2 ph2, and both work really well.

 

[Martin.]

Cheers mate

So I'm assuming when they get hotter on track after a couple of laps they are so out of shape that something is rubbing the caliper? If not what else would cause the juddering etc.. I also take it that warped disc will cause uneven pad wear?

I'll probably just buy another set of Brembo HCs. But I do already have them. Got them from G172 on here and they have done less than 2000 miles. I don't know how long they are expected to last though.

I have DS2500 pads too. With plenty of material left on them!

Thanks for your help..

 

[Chip-mk1]

The juddering is normally the pads wobbling against the disks rather than the disks against the caliper.

If you have a sticking caliper piston that can cause a break to warp by putting too much heat into it.

Are all 4 of your front brake pads evenly worn? (if not it might hint at a caliper piston problem)

 

[Martin.]

Thanks Chip, appreciate your comments.

I never touch my brakes personally so I'll hand it over to my mechanic. I will however check all four pads are evenly worn. Had a brief look at the outside ones on the day and they were but will now properly check all four.

Will also get him to check for any unusual movement or worn bearings. Then to replace the discs with new ones. Hopefully that should all cover it.

How long should you guestimate Brembo HC discs to last? I took off my previous set to replace them with Brembos when I got the car, not realising that the standard parts were actually already Brembos too. I'm wondering now whether the original ones which I took off (which were just put on by the previous owner) are worth putting back on. Or for the sake of 45 quid just getting a fresh new set completely.

 

[Chip-mk1]

We've done over 6K miles on ours on one car and 10K on the other and they are still in really good nick on both.

 

[Martin.]

Serious lol! Can't believe mine have potentially warped in under 2000 miles duff batch maybe :S

 

[George@RTR_Parts]

As Chip has suggested mate, something doesn't seem right, possible sticking caliper?

Let me know how you get on when your mechanic has had a look at it and if you do need a new set of discs i'll look after you.

I've never had any problems of the Brembo HC reported to me and i sell a fair few.

Hope you get sorted soon.

cheers
George

 

[Martin.]

Will do George thanks mate.

I'm kinda hoping it is the discs that have warped, purely because it will be the cheapest way to a solution. Rather than having to get a new caliper if that is the case.

 

[Ian_s]

Could also been pad material deposited on the disk unevenly. I've had this with 2500s and HCs when I got them too hot.

 

[KevF182]

Some pads (I believe DS2500's included, but possibly wrong on that) can need filing down to fit right, or alternatively run without the caliper shims. If your mechanic just fitted them then they could be binding once hot. It's another suggestion and could easily cause the judder.

As others have said, its very unlikely that the parts are the problem so don't go swapping until you know what's caused it in the first place. TBH, you're relying a great deal on your mech to get this diagnosed (who might not have the same enthusiasm for the problem if it can't be replicated on road-test) so unless you're knowing what to look for yourself it could be a hard to sort - Have a go!

 

[Martin.]

Thanks. I'll check the discs for pad deposits. But if there is I would have thought it would be easy ish to pick up.

He was aware the pads needed filing down for proper fitments so he did so.

Before buying anything new I'm going to pass all this info onto him and get him to check it all out.

Cheers