Brake Fade

[mattdyson]

Hi all,

Was hoping for some input.

First a bit of context. I drive a semi track prepared Celica T Sport, with grooved discs, braided lines, RBF600 and performance pads (aswell as various other mods). For the last 2 years and numerous trackdays I've used Stoptech Street Performance pads which have been great except boiling the fluid once (left a bit too long without changing) and munching through some half worn pads at the nurburgring (should have a done a cool down between laps).

So I decided to upgrade to some DS2500 pads and J Hook discs. Which I just had my second trackday on, but ran into issues.

On the first session I noticed the brakes didn't seem to give full braking force, and the more laps I did the worse they got. It wasn't like I suddenly boiled the fluid and the pedal went to the floor, it was like after the initial bite, no matter how hard I pressed, the braking force wasn't increased. The pedal was softer than usual and became softer the more I pressured the brakes but never fell away completely. I came in after a hot lap and noticed the pads were smoking and the disc temp was c. 420 degrees. And after a cool down lap they were about 250-300 (fairly normal). Later in the day after I drove home I did some 60-10mph brake tests and they worked fine again.

From what I read it sounds like Green Fade or full Brake Fade. But that doesn't really add up because I did the break in process (didn't quite get them hot enough to smoke but they did smell) and a 70+ mile track day where I was on the brakes more. Plus I've run my old, lesser pads without similar issues.

The only causes I can think of are either
A) The garage I asked to bleed my brakes with year with RBF600 didn't do it and I just slowly cooked the fluid
B) I gave my rear calipers a service and some new pads a few weeks ago (which involved jiggling the calipers around alot to sort the sliders and pushing the piston back in) which caused issues with them (doubtful as temps looked good and I think poor rear braking wouldn't have been as pronounced as I felt)
C) The DS2500 pads faded, almost straight away, and I have no idea why

Any ideas? Suggestions?

[thebraketester]

Ds2500 are not brilliant.

Try pagid rs29 or project MU h16 or endless mx72.

The brake fluid you chose is fine so providing its fresh that won't cause you and problems.

[mattdyson]

It's just strange what happened considering I already pushed them harder than that at a previous tack-day and they were fine. And in general both me and the car a quite light on the brakes.

That why I was thinking there is a potential other reason before I change my setup again

[F355GTS]

Sounds like the pads glazed. DS2500's are a great fast road pad and for occasional track use but sounds like you're pressing on and need something a bit tougher.

Pagid RS15s (now renamed?) or the RS 29's mentioned above would be my choice

[stevesingo]

From Ferodo website;

Average friction coefficient of 0.42 over working temperature range of 20°-500°C

If your discs were measured at 450°C when in the pits it is likely that they are out of their operating range.

Can't find any info on Stoptechs, other than they have application specific friction compounds.

regardless of pads, I would advise more brake cooling. For a road car which is 1200ish kg and without a huge amount of power, those temps are high.

[iguana]

1- 2500s are crap, might as well use weetabix

2- I bleed out calliper fluid each track day, takes 5mins, note not a full bleed just front callipers & bit out the lines that have got toasty

3- is possible garage didn't change fluid for you.

[mattdyson]

Thanks for the replys.

I've already got a set of small 50mm ducts setup and there isn't really much more I can do without getting more radical with the modifications.

Looks like it might be time for a bigger brake and a better pad to get a more reliable setup.

[Dakkon]

Get Carbotech pads, I run XP8's on my MX5, you might need XP10 depending on how heavy your car is, awesome pads, never had an issue. Not cheap though.

[FTW]

It's worth noting that as the pads heat up and indeed start to cook the compressibility increases and therefor you get a longer pedal and reduced stopping distances.

[wellground]

Dakkon said:

Get Carbotech pads, I run XP8's on my MX5, you might need XP10 depending on how heavy your car is, awesome pads, never had an issue. Not cheap though.

THAT..... Carbotech XP10's for a car like that, you'll love them. I have tried all of them, the feel and response is the best imo. DS2500 are the worst I ever tried.

[MR2_SC]

As above. Firm pedal but no stopping is the pads.

Solution: Get more aggressive pads. Lots to chose from. They'll be expensive and they'll be rubbish on the road but that's the price if you want to be able to stop consistently without fade on track.

Bigger discs/calipers is a minefield of issues with brake bias and longer stopping distances if you don't do it properly. Start with better pads and go from there...

Edited by MR2_SC on Monday 4th September 19:47

Edited by MR2_SC on Monday 4th September 19:48

[NJH]

I've just been through similar with Mintex M1144, pretty rubbish really cooked after one hard stop. Last time out I had Ferodo DS1.11 in there and now I am really happy with those pads, they don't seem to go off and have the added bonus of really smooth progression coming on/off the peddle or when a bit of trail braking is required. Still getting very hot though, I think I will jack the front up and bleed the front calipers before next time out. I am using RBF660 fluid, it goes much darker than fresh fluid when its had it.

[1781cc]

I've got ds3000s on mine and they are solid, what made you go for the 2500s over 3000s?

I'll be going XP12 front and XP10 rears next so the advice here is spot on

[tozerman]

I am surprised at the disdain on this thread for the DS2500 compound. I have never ever had fade with the DS2500 pads and I have tried really hard, ok I may be just a crap (slow) driver but my experience is positive. My only complaint is dust, lots of it.

As others have said try a harder pad or maybe adjust driving style slightly

Cheers.....Tony..

[wellground]

I found that DS2500 glazed over and just stopped working properly. DS3000 were much better, but felt wooden. No progression or feel on the pedal, a bit like Pagid RS29's. XP12's stopped better than XP10's, but didn't last very long. We are all different in our requirements. For progressive feel, I have found nothing better than Carbotech XP10. Hope that helps.

[mattdyson]

I went for the DS2500 as they were the next step up (or so I thought) in terms of compromise between road/light track compared to my previous pads. And I wasn't aware of any harder compounds that are easily available.

Plus my car is a Celica T sport, so c. 1150kg and 190bhp therefore not exactly hard on the brakes. And while I don't daily the car, it's not dedicated for trackdays so I need some cold bite aswell.

I'm going to upgrade to a bigger brake (295 from 275), better pad, flush the fluid and maybe improve the ducts that I already have in place. That should sort it.

What I've learnt is that the Stoptech 309 Street Performance pads I had 2 sets of before are more fade resistant in my application than the DS2500. And are less than half the price.

[IntriguedUser]

Matt,

Unrelated but I have a Corolla T sport and was wondering if you have a moroso oil pan or just a standard 2zz one? I'm super worried about oil starvation so I shy away from pushing hard

[mattdyson]

I run a 1zz sump which has 'a' baffle, just needs a bit of modification to fit the 2zz oil pickup. That and run decent oil and a larger oil filter, always keep it topped up and no issues. I've considered the aftermarket sumps but they also increase the total oil capacity quite a bit meaning more expensive oil changes and longer oil warm up when driving normally. I'm still N/A and oil temps are have never gotten high enough to warrant more significant changes.

TBH I think oil being religiously kept fully topped up and really good quality are the most important things, unless you're going forced induction or seriously sticky tyres that is.

[Order66]

If the pedal is going to the floor I would usually suspect fluid related. While you can get pad compression at temperature you wouldn't expect the pedal to go all the way down - that screams fluid. Do you have rubber brake hoses? Are they new? They could be overheating and expanding - this can give a similar experience to what you are suggesting.

IME DS2500s aren't a bad pad - I suspect they are suffering from an overall poor braking system - possibly too small a disc, is there sufficient cooling, and is your braking technique bad?

[tozerman]

I though about changing from DS2500 last year.
I phoned Carbotech to ask them about their pads, I told the chap my requirements (ie low noise, reasonable cold performance and less dust) he then suggested I but some DS2500

strange but true..