Lost brakes at 100mph

MaxA · 8 Oct 2019

Y2K said:
Guywilko said:

Thanks everyone for your experience and wisdom.
High temp fluid and GT3 ducts on order.
Any advice on pads for track day use?

Click to expand...

When I had my C2 I used Pagid RS-5 which has since been discontinued. I guess any Pagid RS line would be fine (RS-29 the best but might be overkill and some experienced squealing for road use)

I run Pagid RS29s - even in the winter and I'm not dead yet, even if they are compromised for road use (they just need a little heat).

Of course extreme braking in the winter is pretty much a bad idea as it is so easy to overwhelm the tyres and some degree of finesse is required.

And for the record, I run Motul RBF600 brake fluid and change it annually. I have not had any issues with stopping on the track with this set up. It's no fun boiling your fluid... :what:

wasz · 8 Oct 2019

Clanky said:
If you can get pads to fit, Ferodo DS2500 are superb pads.
Instant bite, no noise & very little fade.

For you to loose brakes that quickly, it defo sounds like boiled fluid or the heat affecting the master cylinder seals.

+1 to Ferodo ds2500. Decent pads will help with the heat too.

I have also lost the brakes like that on track as a novice, this was in a brand new road car (mfr jolly) that did not end quite so well....

I also boiled the brakes on my 996 brake on the first track day when I got it (old fluid), but it was more noticeable. I soon re-bled them with decent fluid.

maldren · 8 Oct 2019

wasz said:
Clanky said:

I also boiled the brakes on my 996 brake on the first track day when I got it (old fluid), but it was more noticeable. I soon re-bled them with decent fluid.

Click to expand...

Yes, old fluid is the worst. It's hygroscopic (it absorbs water) and the water boils at only 100C, a much lower temperature than brake fluid which is more than twice that. You can easily reach 100C on the road so change any old fluid you have and don't be tempted to use fluid that has been sitting opened on the garage shelf.

james911996 · 23 Oct 2019

For what its worth, i run Brembo HP2000 pads with standard discs, braided hoses and high temp brake fluid and have had no issue on track.
Did 124 laps of brands indy last month and not one issue with brakes.
The brembo pads don't squeal on road also which is good.

deMort · 23 Oct 2019

I was 17 .. coming back from a training course in Staffordshire ..

Mk 1 escort .. i drove on the M1 for a couple of hours on a very hot day without using the brakes .

There is or at least used to be a large roundabout on the London junction .. i finally hit my brakes to slow down at about 50 mph ..

Brake pedal went to the floor due to heat / water boiling in the brake fluid and extremely old brake fluid at that time.

I remember being young and stupid and just holding the pedal on the floor instead of releasing and trying again .. i sailed across 3 lanes of traffic missing every car and ended up at a stop in the middle of the roundabout ... it was a large roundabout .

That was the day i learnt about water contamination over a period of time in brake fluid and the effect it has

maldren · 24 Oct 2019

I had a similar experience with an old HA Viva, a stuck piston led to a worn out pad which was constantly rubbing and boiled the fluid. I came up to a roundabout and the pedal went straight to the floor, luckily I knew to pump the brakes.

The return of Marty Wild · 30 Apr 2021

Holy thread revival, Batman.

I took my 986 to Bedford the other day. A mate and I had recently put Brembo discs in with DS2500. The racing fluid will be 2 years old come June.

Performance was excellent, car outperformed most there on corners and braking. Took the front wheel off today.... the front pads have a little more than half off them from one TD?! Is that normal?

A friend and I took turns driving, we did let her cool off between runs but obviously other than the lunch break, she never cooled off significantly.

Was my 4th TD, my mate done a few more with some CAT training. I put GT3 ducts and the front arch dam trims on in preparation.

Do I expect to do front pads every two days out on track?! :evil:

Lennym1984 · 30 Apr 2021

In my 986, I used to get about 2-3 track days to a set of pads (fronts). I'm a reasonably late braker but not a driving god by any means. I found the brakes in the 986 to be excellent and far better feeling than the 987

The return of Marty Wild · 30 Apr 2021

Hey mate, thanks for posting up :thumb:

Had an amazing day in the 986, guessing having two there wanting to share the driving equally meant we did spend the vast majority of the day in the car.

Wonder who was killing the brakes more, he was braking later and harder.

What can I do to save the pad life? Will better ventilation help? Lose more weight from the car. Get better on the brakes? Harder wearing pads?

martin t · 30 Apr 2021

Bedford was always my favourite circuit.

I found that the heavier the car the quicker the pads wore out.

For example, my caterham 10+ trackdays pads still almost full.
Lotus exige used 1 set of rs42 (the blue ones) every 3 trackdays and 1 set of 15s (the black ones as it has been a while) every 5 trackdays.

My friends jag xkr 1/2 a trackday and graunched all the way home when slowing down :grin:

My TR6 race car would boil the fluid at the drop of a hat. Heavy car small brake discs, with 250bhp. Very exciting, and often.

DivineE · 30 Apr 2021

I had exactly the same as the OP in my C2 on track, fluid was only 6 months old (changed by a known Porsche specialist), in fairness I could feel the brakes getting hot leading up to the moment but no long pedal.. just an instant boil and pedal to the floor moment. Very scary, OK again after 30mins.

I think the brakes are a bit of a weak point on the 996 3.6 C2, it's the highest performance car to use that disk size and while they feel amazing on the Cayman and are perfectly adequate for fast road use. I think they're slightly under specced for track work.

I fitted the gt3 ducts, Brembo 2000 performance pads and 600 Fluid. Huge improvement, pretty standard feeling pedal but just where the standard pads were getting hot and losing performance, the performance items felt at their best. I chased a 458 on ceramics and had the confidence to keep pretty close in the braking zones, I never found them lacking. I also never lost the pedal again with the new fluid, but did turn the brakes black several times, which left them feeling wooden and took several hundred gentle miles to get back to being grippy again. As above I think the brakes are at their limits in this car.

To the man with the insane pad wear, in my experience this happens above a threshold temperature. With the C2 I found 4-5 laps at a time and let it cool 20 mins won'tcause excessive pad wear, but stay out for 10-12 laps, keep driving it after you feel the brakes getting weaker and you'll munch through pads.

P.s. I also tried EBC Yellow pads on the car and found them to have less fade resistance than standard pads! Better bite and pedal feel but they would cook after 5-6 hard stops. I can't recommend them based on my experience.

The return of Marty Wild · 2 May 2021

Thanks for responding. I thought with a title like this some of the 'Track Rats' would have been brought out of their holes....

Been reading about, maybe uprating the discs could be an idea. Also improving my braking technique to be on them less but harder.

Been speaking to my track mate, we think we definitely didn't let the brakes cool enough. I'm going to look into more cooling down there too. I have a scoop missing on one side that I still need to fit. Not the GT3 ducting, another part before the air arrives there.

The 986 isn't as flat as my Cayman before it. There's a gap in the trays before the brake channeling starts. Wonder if that could be filled in to help smooth the airflow to the OEM cooling parts.

The return of Marty Wild · 30 Oct 2021

Update - Went on another TD, this time running the next Ferodo up:

DS1.11

I cannot claim it to be a completely fair test as I went to Cadwell this time with less braking zones than Bedford, and we were more careful this time to let her cool down a bit.

The difference in pad use was the absolute polar opposite, no visible wear on the pads. Absolutely insane the difference, I now realise that we used nearly 3/4 of the DS2500 at Bedford.

I rate the more track based pads! Oh and Cadwell is incredible!

sim996 · 30 Oct 2021

I've fitted GT3 front brake ducts, dirt cheap.

Rear:
997 turbo gearbox cover
997 turbo rear brake ducts

I'm sure they can be fitted to any 996, the PSM overheats the rear brakes so the 997 cars took on improved ducting.

The return of Marty Wild · 30 Oct 2021

I've got some 997 Turbo rear brake ducts to go on but they need fettling.

Lost brakes at 100mph

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