dende890

Hello,

I have Cayman S 2007. Just bought it in mid Feb. with 11,000 miles.
I modified the suspension, brakes, etc…, but it is not important.
I mostly use it for tracks from VIR to W.Glen. It happened at the Watkins Glen when I pit after a session and the car cooled off slightly. I seat in the car with ignition off and pressed the brake pedal. To my surprise the pedal easily traveled to the floor. I started pumping the pedal and it became firm again. It happened that Spencer *** from Farmbacher Loles was at the track with a client and he as a generous man bled the whole systems, inner and outer. He also made a suggestion that it is an ABS failure and I have to change it to the Racing Unit which is very costly. Now I know that the unit cost $10,675 without installation. Back to the Glen.
The pedal was firm again as it suppose to be. I went to another session and everything was okay during the run. But after pit in I turned the ignition off, wait a few minutes, pressed the brake pedal and to my surprise it surrenders again. After pumping it became firm again. I decided not to do anything this time and went to the track for the next session in an hour. I drive hard as usual but with alert senses towards the brakes. Everything was working perfect, however after 10-12 minutes I stated feeling that after the long straight where I reached 130+ mph the brake pedal started feeling like going some more distance then usual. After some less speed on shorter straights but still hard braking I felt the same and quit driving. With Spencer we went to the Porsche dealership which was with their team of GTs on the track at the time, they immediately connected the computer, checked the system but there was no any troubles found. By the way, ABS or PSM lights were never on. I drove with PSM “on” since I never driven Porsches yet and as I said it was my 3rd day with this car on track.
After that Spencer bled whole system again and I just drove 100 yards, stopped the car switched the ignition off and the pedal traveled to the floor again.
It was possible to pump the pedal to the firm point again.
There was another man on the track who made the suggestion that it is the main, master, cylinder problem.
I had nothing to do but abort the track sessions and go 270 miles back to New York, where I lived. There was no problem with braking on the high way; I even tried some on speed of 90 mph.
The main or master cylinder was changed in a couple of days.
I went to 2 days even at Shenandoah. Everything was perfect. I get use to the car more and more and switched the PSM off.
I drive in advanced groups at all the tracks and drive hard on the car.
I’m not really very clean with the turn in points and usually start turning earlier and thus increase the throttle application earlier in the turn to keep the speed and “fight with the car” often overseeing and braking hard, and short, and some mechanics thought that because of that the overheating happened. I personally wasn’t agreeing with them feeling that there is some other issue.
After the Shenandoah I immediately drove to Thunderbolt and next morning was able to drive 2 sessions without problems. There were only 2 run groups, so 30 min on track, 30 min off. Quite a stress to the mashine. After the third session I was sitting in the cooling off car and pressed the brake pedal and it was traveling to the floor again. After pumping became hard and then surrendered to the floor under the foot pressure.
I started the 4th session caution and quit very soon feeling that the braking pedal is started surrendering slightly again after hard braking.

Next the Titanium Shims were added to my calipers to deal with excessive heat, the brake lines were bled thoroughly again with Motul RBF 600.

I went to the Glen, last year I had 39 track days, and on the third sessions everything was back again.
I quit and went home angry to the Porsche f… engineers.

I spent couple of days reading diff. articles about such problems with Caymans and now I’m looking for people who already dealt with it and want to know the result.

There are a few suggestions I picked up from what I read.

1. Change to expensive Bosch ABS Racing System.
2. To find some other less expensive Racing aftermarket ABS System.
3. Find the way to cool down the fluid before it gets to the original ABS.
4. To trade the car in for BMW M3 2006 which I had before and loved it.

So anybody, who already went through such problem and solve it successfully in any of the first 3 solutions, please share the experience. Help me and others who is already desperate and those who are going to get in to the troubles sooner or later in the future.

Or is it something different and not ABS at all?

Thank you,
Lev.

MJones

You may want to post this question over at the Racing & Drivers Education Forum

My best guess would be the "power brake accumulator"
It is not the ABS syatem

dende890

Thank you MJons.

Unfortunately I found this web site very difficult for me to navigate.
I have no idea how to find "Racing & Drivers Education Forum" to post my article.
If you would be so kind and give me the link.

Thank you,
Lev.

FTS

here is the link to that forum: https://rennlist.com/forums/racing-a...tion-forum-65/

I am not sure if you checked here, but there is a useful discussion here: http://www.planetporsche.net/cayman-...ms-track.html; although no solutions yet.
Thank God I don't have this problem on my car, it can get very scary at VIR or WG if the padel goes down on you.

elh0102

Lev,

Not that you don't know it, but you have a problem. I have had some of the typical Cayman brake problem on track. But the more typical problem is, I believe, heat related, and can usually be addressed through some combination of adapting your driving style, cooling ducts, proper fluid and pads, etc. I'm also in advanced run groups, and have a lot of VIR experience. Since I drive relatively conservatively, I have changed my style a bit to compensate for the Cayman brakes, and it works fairly well. I can tell you with great certainty, based on your described driving style, the Cayman brakes will be a challenge for you. But, your car has something else going on with it, and my advice is to stay on your dealer to get the assistance required to diagnose it.

dende890

I have slotted braking dicks, Padig yellow, black pads, SRF Castrol fluid, GT3 air scoops.

The brakes are never faded or disappear, it is just the pedal was traveling longer after an hour + in total track time and I was afraid to loose it completely.
The car brakes excellent and off the rack on highways or in the city is more then perfect.
I read a lot and received a lot of info and I think that I have to turn off the PSM to unload the ABS system from excessive work for which it was not designed, however Porsche talked a lot about that the car could be used on track.

Lev.

dende890

Forgot to mention Titanium Shims in calipers, the calipers original though.

FTS

I don't think the original or GT3 air guides/scoopes really do anything significant against track driving.

dende890

Here is again, but concise info on the problem.

Hello,
I have Porsche Cayman S 2007 14,000 miles.
The brakes work perfect. But if I stop the car completely with running engine and keep moderate pressure on the brake pedal it will travel to the floor.
Then I pump 3-4 times and it is very firm, however if I still uply the preassur, bigger then the first time the pedal slowly, but surely surenders to the floor again.

With engine "off" everything is the same but when I pump the pedal second time after it reaches the floor, the pedal will surrender and go down but not completely to the floor.

There is no leakage in the system.
Slotted rotors, Padig black pads, Castrol SRF fluid, Titanium shims in calipers.
The master braking cylinder was changed very recently without any difference to the problem.

What is it?

Lev.

dende890

Forgot to mention GT 3 air scoops. Everything imaginable is there but the result is negative.

Definitely the fluid is leaking inside some system and then goes to default state.
Where is it leaking, ABS, PSM?
How to check it?
Again, no leakage to the outside of the braking system.

Lev.