Brake Pedal is "stucking" on 97 Boxster

[Simon2]

Hi everybody,

this is my first post and i guess i have a kind of "unique" problem with my brake pedal. I´m from Germany so please excuse my english.

I have a 1997 Boxster with about 75000 miles on the clock. The problem is, that the brake pedal is sometimes "stucking", which means that it doesn´t come back the hole way, so i have to put my foot behind the pedal and move it back to release the brakes from decelaration. This most of the time (only) happens when i use the brakes at low speed, not when i´m driving at higher speed and use the brakes harder.

I used some spray oil here and there and released the nuts betwenn the master brake cylinder and the brake booster, which made the pedal going easier backwards for 1-2 days. My mechanic - he´s not familiar with Porsche - told me, i should intall a new master brake cylinder to solve the problem.

What are you guys thinking about that?

Thanks a lot,

Simon

Edited October 3, 2008 by Simon2

[wvicary]

There is a problem with water migrating into the brake booster. Porsche has issued a TSB on the problem which requires a new booster,sealing kit and brake pedal.

[Simon2]

Thanks a lot for the answer. Is this like a recall and does that mean, i can bring the car to the Porsche dealer and they will fix that for free?

[Loren]

Thanks a lot for the answer. Is this like a recall and does that mean, i can bring the car to the Porsche dealer and they will fix that for free?

No it is not a recall. It is a TSB (Technical Service Bulletin) which says this "could" be a problem on some cars and how to fix it. It would only be free if your car is under warranty or was covered by a Porsche CPO contract.

[Simon2]

Thanks Loren, i understand. Looks like it´s TSB 4770. Brake Booster Seal at Firewall Changed. Let´s see how much work (and money) this will be...

[Tool Pants]

http://www.renntech.org/forums/index.php?showtopic=15633

[Simon2]

ToolPants - thanks a lot for the link. Thant´s what i was looking for.

I´m thinking about buying a used brake booster. I know that the master brake cylinder, who was built by LUCAS, is the same one that were used in a lot of AUDI and VW models .

Does anybody know, which part# from AUDI or VW is the same like the Porsche brake booster? I was thinking about part # 8D0 612 105 G ???

[Tool Pants]

You need to see if water in the booster is the problem.

I do not have a way to cross reference Porsche to VAG parts. But if you go here and look up the booster it says it is also for an Audi A4/A6 and VW Passat, and has the years for those vehicles. http://www.partsamerica.com/

[Simon2]

I bought the special "Porsche" Torx 45 today, so that i could remove the lower screw that holds the brake booster and - there is no rust on the screw. So it looks like it´s not the brake booster. What else could it be - the master brake cylinder?

[RFM]

The rust is inside the booster, there is water infiltration via the flange seam of the booster.

[Simon2]

Yes, i know. Maybe i will try to open the brake booster tomorrow and see if i can find water inside.

[Simon2]

Today, i took away the vacuum connection from the booster, to check if there´s water inside the booster. I put a long small piece of plastic inside, took it back and there was water on it.

Then i put a flexible tube inside the booster and sucked. No questions - it was not tasting very good...

But at least, there was about half a liter of water inside the booster. This was caused by a blocked hole near the batterie, where the water could not go through. So the water stayed up there to an amount, where it could go through the bad sealing into the booster.

The problem is still there. So i will buy a new booster and install it soon.

So if you also had a problem with the blocked water hole and your brakes are still fine, but you want to ckeck the booster - just take away the vacuum connetction and look for water inside.

17. okt 2008: I received my brake booster today, a used one from 2000 boxster. I could install it without disconecting the brakelines from the master brake cylinder. Now the car brakes perfect. Thanks to everybody who took care of my problem and helped me out on that!

Edited October 17, 2008 by Simon2