jeremyck23

Just came back from a drive and going to try my best to describe what I think is wrong with the car, and hopefully you guys can chime in and let me know your thoughts.
Some background info, upon purchasing my 2001 996tt last August, I found out that there was something wrong as Pentosin began leaking from the front reservoir. The clutch feel is very vague and after researching, I decided that I want a permanent fix and went with the bbi setup.

After installing the bbi clutch slave, the car was feeling great..until about a week or so later, the clutch sticked to the lower half of the run and after pumping it many times, the clutch would return back up but it seemed to me that the engagement point became much higher than before. I suspected it was caused by a bad master cylinder and so we installed a new TURBO master cylinder and things started to get interesting...

I started noticing that, when the car is cold, I have several inches of free play on the clutch pedal, and as the car warms up, the clutch engagement would get almost all the way to the top of the pedal(very stiff too).

I talked to the mechanic who installed the bbi slave and he seemed to think that it's normal and he thinks that it takes time for the system to run in. Now I am no mechanic myself, but having owned a few manual cars, this has never happened to me and that's why I am writing to seek advice. The mechanic almost mentioned that since the BBI unit didn't come with a Stainless Steel braided line, it could be the cause. Other than that, I cannot think of another reason where the delta in temperature could make any difference.
I am also thinking maybe the newly installed Master Cylinder is no good, and that I should install a new GT2 master cylinder instead.
Would really appreciate if you guys could give me some feedback on this.

Jferrante

My guess is there is still air in the system especially with the master cylinder change. These clutch parts, if aren't bled correctly will sho through stiffness of pedal and clutch engagement points. I am no expert on the BBI since I have a full GT2 conversion but there are plenty here that can chime in further.

wice.lt

I am not sure if BBI setup is using Pentosin or regular DOT fluid, but that might be the answer. I know GT2 is not Pentosin and it will fail shortly after installation if you use wrong fluid.

s65e90

This is a definitive sign of a failed clutch master cylinder. Unfortunately it seems to happen after these swaps. Many people (including myslef) have gone through 2 masters right away as after the swap the first fails.

911mhawk

BBi should be able to help support their product, have you or your mechanic called them for help?

wross996tt

bleed the system...

LOLS996TT

Like a few of the others said it might need bled again if it wasn't done right the first time. Really need to flush a lot of brake fluid through the system to get as much of the pentosin out of it otherwise it will break down the seals and trash the master.

horsepowerfarm

Do not use Pentosin with with the BBI slave. I would recommend a flush and re-bleed of the system and use a high quality DOT 4 brake fluid. Also, you will want to replace your pedal helper spring with Porsche part #997.423.081.06. I have had very good luck with the BBI's slave cylinder.

32krazy!

if he ran petosin thru the slave its to ;ate for another flush. seals are already shot.
time to call bbi and tell them yet another one of their 1100$ systems has crapped out. do the oem setup once and forget it

jeremyck23

Thanks guys...
We already used Dot4 ATE SL.6 in the very beginning(IT'S NOT THE HIGHEST GRADE ONE), and replaced it with a brand new TURBO master cylinder once already. Not sure whether Turbo's Master Cylinder and GT2's master cylinder are any different. Maybe I will try using the GT2 master cylinder this time, along with TYP200 Dot4 and a steel braided hose...
Could it be the pressure plate or any mechanical parts?

I tried contacting BBI and the technician told me he believed its air in the system, but my mechanic was 100% sure its not.

What's the safest way to bleed the entire system without blowing another master cylinder?

911mhawk

I've bled my hydraulic one once after install just like you would brakes.
Pump the pedal a few times with the car off, keep light pressure on the pedal while your mechanic loosens the bleed valve. Press pedal to the floor, repeat a few times until the pedal seems "normal".

Did you make sure to fill both reservoirs and then turn the steering wheel lock to lock with the car running before you started bleeding initially? If not you probably have fluid in the lines.

s65e90

BBI slave bypasses PS.

32krazy!

turbo master uses different seals than the gt2 unit.

user a motive power bleeder and pressurize the system then open the bleeder at the slave with a clear tube and catch can. no bubbles its bled. if there were any petosin left in the system and you ran it thru the bbi unit you likely killed the seals in the slave unit not the master.

Mtrboatvr6

This exact thing just happened to me with my BBI install Today. Mine is about 3 weeks old at this point. OP do you have any more info on a resolution for yours? I would be interested to see if it was the master.

32krazy!

if the system has even the slightest amount of petosin in it it will fail the master or the slave regardless of its oem or a bbi unit. the system has to be completely and fully flushed BEFORE any parts are installed.

so many people install the new parts THEN try to flush the system effectively ruining the new parts.