roadsleeper

Hi all,

Just joined this forum, sadly one of the main reasons for joining is to gather some information on a case I am trying to put forward to Porsche Asia.

My brother was tracking our 996 Turbo cabriolet this past weekend at Sepang race-course in Malaysia. Long story short, he was coming down the back straight doing around 200kph during his 5th or 6th lap, and as he was coming up to the left turn, the brakes failed on him and the Turbo basically ended up running through the gravel trap, across a service access road and into the armco barrier. Both airbags came out (front only, sides did not), and the roll-over bars popped out too (the soft-top was up, and the car did not flip).

According to him, as he was approaching the turn he jabbed the brakes to bleed off speed and when he did this the brake sank in with no response. He tried again and the pedal went to the floor. So he immediately began pumping thr brakes to build pressure, but nothing happened, and the crash occured.

I thought it might have been a popped seal or brake line, or maybe a master brake cylinder failure, and when I went to see the car on Sunday, I was expecting to see a bone-dry brake fluid reservoir. Instead, the reservoir was at the MAX marker line, and there were no signs of any brake fluid drips (plenty of coolant though). I'm sort of perplexed here as I really have no idea what could have happened so that this would transpire. The car is serviced regularly, albeit we didn't have DOT5 or any other sort of upgraded fluid in there, it just doesn't make sense that the brake fluid would boil over after just 5 or 6 laps (unless the stock stuff Porsche uses is junk, which I doubt).

Any input from other RennListers would be very helpful.

PS: for those with a morbid fascination, I've attached a pic (it's a 2004 Seal Grey Turbo Cab with the X50 package)

Tse-Tse

Sorry to hear; hope it fixes OK. Glad he didn't get hurt...

Oak

no fun when the brake/fluid overheats. sometimes there is no warning. was the brake fluid flushed or atleast bleed before the track day? hope he's ok.

Woodster

I am thinking what Oak is thinking, taking a stock car with stock Brake pads, stock fluid,
and no flush/bleed before a high speed event is very risky. With the above precautions,
many of us have had amazingly successful high speed track days with no fade.

good luck, that had to have been terrifying!

Marty K.

ltc

Assuming no mechanical failure, I'm guessing that there was moisture in the fluid (when was the fluid last changed?), that the brakes were likely not bled prior to the start of the track session (were they bled?), and assuming sufficient pad thickness at the start of the run (were they well above 50% thickness remaining?) and that the brakes were beginning to retain heat after multiple laps with heavy braking (did your brother notice the pedal was becoming 'soft' and/or was he using the brakes quite a bit?) and the cumulative effects led to the loss of braking due to boiling of the brake fluid.

I don't know what type of case you could put forth to Porsche Asia, unless there was a mechanical defect.

1AS

This is a story i've heard before, and what I've seen may not apply to you. You needed to check the brakes when the car came back to the pits. If brake pressure could lock the wheels, your brother would be "misrepresenting" the story.
I really don't see boiling the fluid in 5 or 6 laps. I can see getting into someone else's oil ( which feels like you are on ice) or just making a mistake (?foot on the wrong pedal) and then needing to come up with a story.
In the end, if the dealer finds nothing wrong with your brakes, this will be a "dog ate my homework" story. Think about it: 5 laps. First lap warm up- almost no brake temp. Laps 2-6 building up speed, no evidence of brake failure. Lap 6, 120 mph, downshifting and braking and straight off the track" If the brakes failed when he let the clutch out, engine braking would jerk the car, and he should have gone off tail first, with the asc doing its best. Thereis a memory chip in the airbag (I have been given to understand) that can shed a bit more light. Give your brother a polygraph before you stick your neck too far out (not really serious-but you get me-right?). AS

tkerrmd

either poor pre event car preparation or driver error, I doubt you will have any kind of "case"???

ltc

Novice drivers in high HP cars (re: who LOVE the right pedal) in a car with marginal pads and fluid can 'use too much brake' and quickly boil the fluid.

Carrera GT

You certainly have a case to take to Porsche. Whether it's a strong or likely successful case, you won't know until you try.

I'd go to Porsche with the facts and without having allowed any mechanic to fiddle with the car. Given the basics:

in-service date of the Cab
odometer mileage
service records

I think Porsche is obliged to inspect the car, perform a litmus test on the brake fluid, check the rotors for wear and all other components for failure. Measure the brake pad thickness and check the OBD for any codes.

They might find a failure. Otherwise, they might cooperate in significantly reduced costs to repair the car to factory perfect condition. Those air-bags alone will be a pretty penny. Nothing can "un-do" the body damage, but if they did find a failure in the car, they might offer a new replacement or a buy-back.

You have to try.

In short, if the car has good fluid and pads, there's no reason to suppose it boiled the brake fluid. "Nothing at the end of the straight" is a common enough report, especially on 996 Turbos. Some drivers can work the brakes very hard and five or six laps is ample to bring the temperatures up and soak through the pads, through the pistons and into the fluid. If the car is 12 months old, the fluid boiling point could have dropped significantly. But all that is neither here no there. Put the simple facts to Porsche. Don't even begin to talk about drivers or track time or the number of laps. Just say the pedal went to the floor, report the basic facts of the car and let them go about deciding what they're prepared to do to help an obviously valuable customer.

Good luck.

And count your brother very, very lucky to be alive.


Cheers,

tkerrmd

tell porsche it happend at the "track" you will have NO CHANCE!!!!!!

I suggest the moderator of this forum changes the title of this thread to something more appropriate like......well I'll let you guys fill that in

1AS

I haven't ever worn out the pads on a tt, but don't we have wear sensors? I guess I could see losing one brake if a pad disintegrates and a calliper wrecks the disc, but wouldn't you expect that the remaining brakes would stop the car? I can't respond to the boiling brake fluid issue, but it raises a few more questions. After the 5 hardest laps I ever did, I didn't have any problems using stock fluid, and OEM pads. That was on a very hot day.

How many miles on the car, on the pads, and of those miles, how many track miles?
Any recent service, and if so, done by an expert?
How expert is your brother? Can he really get going fast enough to boil the fluid in 5 laps (assuming one warm up)

I've seen brake failures (experienced boiled fluid in a race car myself), and have seen claimed brake failures that were driver error.
When there is something unquestionable, like a broken-off pedal, all the answers are clear.
When someone claims failure, and the brakes still work, the answer is still clear.

Here is a question for tt track junkies:
When a tt boils the fluid to the extent postulated, is the resevoir still full when you check after cool-down? Just asking, because in my case, it wasn't, but that wasn't in a tt.

One element is unclear to me. When slowing from 120, you'd start to apply the brake, declutch, blip, downshift, and release the clutch while braking hard. Releasing the clutch with no braking should jerk the car while it is slowing down. If you are turning, you spin or run wide, not bang the nose srtaight on. To go straight off, you generally need to lock the brakes (not possible on our cars), be on something really slippery, or decide to steer straight onto an escape road. I do accept that you can't really steer in gravel.

Jabbing the brakes to bleed off speed, and pumping repeatedly while forgetting to release the clutch or downshifting is odd, unless you forgot to mention it's a tip.

Lastly, if the car had many track miles and wasn't serviced, or was serviced by a non-dealer, I don't see you as having much luck. On the other hand, I'd be really interested in the answers to the questions posed by CarreraGT.

Oak, what's the least laps you've seen necessary to boil brake fluid on a tt? (Granted, it depends on the length of the straight and speed the driver carries onto it) Let's assume long straight and a driver who is carrying good speed when he enters.

Here's one for Tom: When do you "jab" the brakes to bleed off speed? If Tom doesn't answer, will somebody? AS

1AS

Last thing (for real, this time):
You want Porsche to pay for all the damage that occurred to the car as a consequence of track-use brake failure, right?
If it happened on the street and the brakes were absolutely functionless when checked in the shop, but there was normal maintainence, I understand your point.
Even if the brakes are without function in the shop, and you can prove you boiled your fluid (big if), I doubt you can get coverage for track-related failure.
If the brakes work in the shop, and you contend you boiled the fluid, I doubt you can get coverage, since nobody can boil the fluid in street use, and they will discern where the accident occurred.
Since this is Porsche Asia, and not the dealer, there is no pre-existent relationship, so unless you dad is president, I see little hope.
It's still a mystery, so I hope you get an answer and share it, even if it's just a fib by your brother.
Now, I think I'm done. AS

Carrera GT

Just so long as the complaint doesn't include "My brother was in 3rd position with a credible chance at a podium finish!"

Carrera GT

If the pads were more than 50% worn they would be communicating a lot more heat from friction with the rotors to the backing plates (and from there to the pistons and thus to the fluid.)

He needs to present just the documented facts of usage and service, not the expert skills or the number of heat cycles in his track tires. Trying count track days or laps or whatever isn't going to come into the decision. The given dealership has to arrange for the local Porsche HQ (eg. PCNA in the USA) to send someone to inspect the vehicle and make their own determination.
I think it's impossible to count the fairies on the head of pin and it's impossible to know what happened in this case or in many such "track happens" cases. Even with a black box linked to sensors on all conceivable parameter measurements, there's still a margin of doubt.
The braking system is not entirely a sealed system and it does lose fluid. But I've seen a 996 Turbo the day after terminal brake fade (over-run T2 at Laguna) and the fluid level was unremarkable. Boiling is the expansion of gas carried into the system (usually with water) and causes the hydraulic fluid to be come more compressible. I haven't seen it push out past the cap (although I've seen evidence of over-flow but that might just be normal seepage or poor clean-up after a top-off.)

Most of the description here seems to be a bit vague. I think the words chosen reflect more of an "English as a second language" than a forensic record of the facts.

Me too. : )

On a hot day, I think you could boil the fluid in a daily driver Turbo taken to the track in the space of one hot lap or two, especially if it was a demanding track and you spent the whole lap ducking and diving and trying to get a point-by around someone a bit slower. Keeping in mind a Turbo (especially a Cab) is a relatively heavy 911 capable of picking up a lot of speed between turns -- in a battle between engine and brakes, the engine will cook the brakes in a big hurry.

My main reason for contributing (?) to this thread is to encourage approaching the selling dealer in a no-nonsense fashion to see if there was a legit failure. For all we know, the ABS pump died. Anything could have caused a pedal to the floor failure. I agree with the "most likely cause" but why not get the dealer to test the car? And in my experience there's every reason to expect the dealer will come back with at least an offer to defray the cost of parts to get the car back in shape. Just from what I can see, if this was in CA, repairs would be around US$20K (panels, paint, suspension, wheel(s,) brakes, air-bags, cabin trim, etc. This was not a cheap "off" so it's worth looking for some good will if nothing else.


Cheers,

spideyTT

The Sepang F1 track is hard on brakes and with ambient temps in the 90+ F , ............

Coupled with probably almost no "pre-race prep" , i can see the brakes fluid boiled and having brake fade occur.