Master Cylinder

[gacook]

I'm replacing my Master Cylinder tomorrow. I've already looked over the procedure on Clark's and it seems relatively straight forward. Any of you have additional insight that would be valuable for this task?

[skyhawk5421]

Upcoming master/slave cylinder replacement - Rennlist Discussion Forums

[Bukowski]

Porsche 944 Replacing clutch hydraulic - YouTube

So good - so entertaining too - like a cooking show!

I recommend using the captions in English but listening to Dr944S2 speak in German for the full Porsche experience.

[Arthropraxis]

Make sure you bench bleed it first.

[John_AZ]

Now for the "what can go wrong" things.

Be careful on how you remove the reservoir. If you break off the bottom nipples, it is a long wait for a replacement.

Same applies for the nipple to the clutch MC.

Replace the short hose to the clutch MC. The blue hose is about $11 a meter on Pelican.

Do you have new MC reservoir grommets?

You did get ATE MC for an ATE booster or Girling MC? Not interchangeable unless you got a new steel MC that can be used on both.

Most members will say go with ATE DOT 4 Super Blue.--about $16 a liter and up.

BUT....If you do not want to switch now, go to your FLAPS (friendly local auto parts store) and get a quart of Valvoline DOT3/DOT4 synthetic mix $7 a quart. This may be cheaper than using Super Blue and bench bleeding and flushing the lines with the expensive stuff.
Make sure it all works and do the Super Blue later.

GL
J_AZ

[Gawernator]

+1 on being careful with the hose nipples. I accidentally pulled mine out when replacing a hose and was really just lucky I didn't break the nipple itself or ruin the little seal it sits in.

[Qfrank]

I replaced my master cylinder, a girling unit, on my 968 2 years ago, and my pedal,is to the floor after an autocross.

I did not realize there are different applications, based on booster.

How do i know what i have as far as booster, ATE or Girling compatible?

Thanks,
Fq

[Gawernator]

My ATE booster has a big fat ATE sticker on it, might say on the outside of yours.

[Qfrank]

No ATE sticker on my booster, may have been removed. Girling has worked fine for 2 years, no issues whatsover. What is the deal with the ABS needing to be bled as well?

Pedal is soft, but when pushed hard,, it will travel down to the floor.

I will have system bled first, and new fluid added, to see what happens before replacing MC.

[Gawernator]

Yeah I'd definitely try new clean fluid first. Then check for ballooning brake hose etc because the booster is pretty expensive