Brake discs and pad depositing.

[Clarkey]

So, after the track evening my brakes are pretty messed up. Over the swept area of the discs is loads of fine ridges and it sounds a bit grindy when braking.
I assume this is pad material that's been deposited over the disc surface. Question is, will it go away with a bit of time or are the (nearly new :/) discs toast?

Next question. It became clear very quickly that the brakes are woefully inadequate on the track. First time I went out I managed just 2 laps before the pedal went to the floor and I had almost no brakes at all. For the rest of the evening I was lifting on the straights to keep the speed down and braking much earlier and more gently. This sucks, I could have been much much faster had I been able to brake where I wanted to.
Anyway, the actual question is would moving up to Yellowstuff (from nasty Greenstuff) do the trick or should I be looking at something more serious? Bearing in mind this car is primarily a daily driver but I do intend to do 2 or 3 more trackdays this year.

 

[InvaderGIR]

How fresh/old is the fluid and what DOT is it? Sounds like you may have just boiled the fluid with some overly enthusiastic braking.

People over on e36coupe.com don't rate GreenStuffs at all but I can't remember what they do say is good for road & track use. I know quite a few did/do run Performance Friction Z rated pads and other PF compounds (these are best found via the PF deal buried in the forum somewhere for discount etc.).

 

[Ev0]

Greens are usually better on smaller hatches, for something a bit bigger like an E36 I'd have thought Yellows or Reds would be more suitable on track.

 

[Matt82]

Pedal to the floor in my experience was fluid related. If the scores go round the swept area thats pretty normal

 

[LeMson]

I'd try fluid and maybe braided lines first, then pads, then discs/calipers?

 

[Clarkey]

Fluid is Halfords standard DOT4, 3 days old. So you guys reckon I should stick with the discs, fit yellowstuff pads and some ATE super blue fluid?

 

[Dogbreath]

You could fit Yellowstuff, or you could fit some decent pads like DS2500. Greenstuff is barely a fast road pad, it has no place on a track unless fitted to a very light car.

 

[Simon]

You've abraded the disks rather than let them work by adhesion by the sounds of it. Overheating is the cause usually. Get some better pads next time and add ducting

 

[Matt82]

Ive had plenty of brakes fade before but the pedal does indicate that the fluid boiled. That could be due to the fluid or pads or both.

Sadly it looks like its upgrade time and then try again. Same pads on the back?

I knew a fella with a similar issue to you, changed everything but had left the rears as no brand stuff. When he changed those everything turned out ok and it was the inadequate rears boiling the fluid

 

[Simon]

Fluid is Halfords standard DOT4, 3 days old. So you guys reckon I should stick with the discs, fit yellowstuff pads and some ATE super blue fluid?

Dot 5.1 would make more sense for a start, maybe something suited for track rather than generic fluid.

It's hard to comment on if the pads fix it as depends on what size disks you have and how heavy car is amongst other factors.

Braking harder will be better for the brakes. Once they start to go off and you start braking earlier it's game over. The brakes have less time to cool and as they are relatively cooler then the heat transfer rate is lower.

 

[Clarkey]

Rears are stock yeah, I figured that would be ok since greens are only an oem replacement type pad.
Brake cooling ducts are standard fit on these btw, pretty decent size ducts too.

So, DS2500 then, are these really serious then, going to make a load of squeal and chew up the discs?

 

[Clarkey]

Dot 5.1 would make more sense for a start, maybe something suited for track rather than generic fluid.

It's hard to comment on if the pads fix it as depends on what size disks you have and how heavy car is amongst other factors.

Braking harder will be better for the brakes. Once they start to go off and you start braking earlier it's game over. The brakes have less time to cool and as they are relatively cooler then the heat transfer rate is lower.

It's a heavy car 1400kg and small discs 285mm or so up front I think. I hear what you are saying about the early braking but it did work for me. After a while I did try and see what would happen if I did some hard late braking and within 1 lap the pedal went to nothing again.

 

[Simon]

Yeah early braking will reduce brake fluid temps which sounds like your issue. Pedal to nothing. DOT4 boils at 230C whereas DOT5.1 is 270C, that's a big difference.

 

[Will]

I'd get some DS2500s and proper fluid, Motul 5.1 or RBF600. Can really recommend the DS2500s, take proper punishment with the right fluid! Still decent pedal feel on the road, usable enough from cold, and not too noisy. Dusty as hell mind.

I think Greens and halfords brake fluid will just never be quite the job with an E36 on track, I wouldnt be blaming the discs. 285mm discs on a relatively heavy car doesnt sound ideal either, any easy bolt on upgrade from another model elsewhere in the BMW range (ala the 300mm upgrade for my car which was cheap as chips)?

 

[Gibbo]

Hi m8

If your working to a budget, then EBC Yellow stuff is an OK pad, the green stuff are for road use and they are absolutely terrible.

Yellow stuff is for track work, but also fine on road, my 525i had these which had no issues round Donnington and zero brake fade.

DOT 5.1 will be better, but its still possible to boil that, you need to look at Castrol SRF or Motul RBF brake fluid, far better.

I'd not go with DS2500 pads as some recommend, they can still fade on track and have a slightly wooden feeling to them.

 

[Housey]

I run red stuffs on the race car, never faded once after many many hard laps and some races. I have some nice new yellow stuffs for the road going one, they are currently sitting in their boxes, I really must get around to fitting them before they evaporate.

 

[Ev0]

Castrol super dot 4 isn't too bad to run either, as high a boiling point as 5.1 iirc.

 

[Dogbreath]

I'd not go with DS2500 pads as some recommend, they can still fade on track and have a slightly wooden feeling to them.

A friend of mine has a Civic VTi tarmac rally car which is currently running the standard size (tiny) front discs with DS2500. The car regularly comes into service with the discs visibly glowing, yet he has never experienced fade with these pads. The only only bad thing that happens is they start crumbling around the edges if you abuse them that badly. DS3000 are better but he had a hard time sourcing any.

He tried a set of Mintex race pads and they felt spongey and chewed through a set of discs in short order - not great for £150 worth of pads.

 

[Gibbo]

A friend of mine has a Civic VTi tarmac rally car which is currently running the standard size (tiny) front discs with DS2500. The car regularly comes into service with the discs visibly glowing, yet he has never experienced fade with these pads. The only only bad thing that happens is they start crumbling around the edges if you abuse them that badly. DS3000 are better but he had a hard time sourcing any.

He tried a set of Mintex race pads and they felt spongey and chewed through a set of discs in short order - not great for £150 worth of pads.

My experience of DS2500 was on larger car, similar to Clarkey's.

Mintex, horrible horrible cheap pads, don't touch those.

As far as budget pads go the EBC yellow/red seem very good for the money, but the greens are just woeful.

 

[Gaygle]

Wouldn't grooved and drilled discs help with the fade also?