Orry

For quite some time I need to top off my brake fluid I notice the low level by an illumination of the PDAS, Brake and Central Warning Light.

I guess that I topped off approx 200-250 ml over the last 2 month

I checked if I have a leak, but my garage floor is completely dry not a single drop. My wife thinks the car smells a little different little like burned oil


Any ideas what it could be?


I am thankful for any hint.

Thanks Orry

tbennett017

is your clutch master leaking into the footwell of the car?

Bill Verburg

C4 brake fluid can leak into the transmission

alexjc4

As Bill says it could be your 4wd interlocks leaking into the gearbox or onto the undertray and then the leaked fluid being blown away when on the move.

You could unplug the pdas solenoid in the trunk, this will isolate the interlocks/slave cylinders for the pdas. You won't have pdas while its unplugged but you should be able to rule out one possibility.

elbeee964

...and to do this means removing the pedal area carpet and plywood panel.
You'll need a Phillips head screwdriver and metric hex key to unfasten that panel.

Orry

In other words the disconnect of the solenoid disables the circulation of the fluid ? What does it mean if the interlocks are leaking what would be the next step ?

FeralComprehension

No, you disconnect the PDAS from the tranny to see if it's leaking there; the disablement comes from the fact that PDAS can't function correctly with the slave dismounted. If the slave is leaking, so far as I know the only solutions are new or used-but-working slave from Porsche or a breaker.

alexjc4

Actually I was suggestion unplugging the electrical connector from the pdas solenoid in the trunk and thereby isolating that part of the hydraulics, then driving the car for a while to see if the fluid level still drops. If it does, you know its not the pdas slave cylinders leaking.

Of course you can also check by unbolting the slaves at the gear box, but at a rate of 100ml per month i'm not sure the leak would be obvious.

Orry

So i checked tonight the foot well even though I did not take the plywood away I could see that the carpet was drenched and the paint was of course gone for me a clear indication of leaking brake fluid.

I have a pretty good mechanic that has not disappointed me so far, however since the clutch is tight into the brake and PDAS system I am afraid that he will do more harm than good.

Any recommendation and what are the potential pitfalls ?

Thanks Thomas

Rocket Rob

If you have brake fluid in the pedal area, then I would suspect you have a leaky clutch master cylinder. They are not too bad to replace. Its just awkward to reach under the steering wheel. Take a look at this thread, it shows the master cylinder. I've replaced mine. If you are doing it yourself, I would suggest having a pressure bleeder (Motiv) to help bleed the clutch when you are finished.

https://rennlist.com/forums/964-foru...solved.html#21

Orry

So I checked the clutch master cylinder, even though the carpet was wet there was no evidence for a leak, it seems that my predecessor has changed it at one time.

I am back to the point of fluid leaking into the transmission ! I am not sure how I can get closer to the issue or do I have to turn it into a shop to get it checked out ?

Could you describe to me what exactly needs to be done ?

Thanks Thomas