Porsche Enthusiasts Club Forum

The brakes in my 944 had always been pretty poor but I got used to it. Usual situation where they were solid with the engine off and with it on, the pedal would slowly sink to the floor if the brake pedal was pressed. Decided to try pressure bleeding and flush with new fluid incase there was air/water in the fluid as it was quite old. Brakes still super squishy so deduced it to be a master cylinder. Took it off and it has definitely been leaking back against the servo. Took it to bits and there doesnt appear to be any obvious wear but at the same time I dont really know if there are any tell tale signs?

Basically the main question is, the reservoir has 2 sections, one fillable via the cap and the other with a blanked off plastic nipple thing. Do I need to prefill this some how before fitting it or can I just bung it on the new master and fill the reservoir then the other section will fill itself with however much it needs?. Also, is there any specific way with a new master for bleeding it before fitting? Or is it a case of pressure bleeder on and attack it on the car? Need to get this done this coming week and want to know the whole procedure before I get stuck in!

Just fill and pressure bleed as normal. The redundant welded up pipe is from where an automated pressure bleeding system is used in the factory.

you can't buy rebuild kits for master cylinders anymore. Better to bite the bullet and fit a new one. It can make things easier if you bleed the master cylinder before it goes on the car. If you can make up three short lengths of brake pipe that go from each outlet back into the bottom of the reservoir. Have the master cylinder horizontal (dont squish it in a vice!!!) Fill reservoir with clean fluid and press the piston gently in and out until no more bubbles come through. Refit it to the car while still full of fluid and just take out each short pipes in turn and reconnect the actual brake pipes to minimise fluid loss. If you have problems thereafter have a look at my previous post - good website link.

PS I have just done this and have three short pipes now surplus to requirements, you can have them if you PM me a postal address.

Did mine today ...built a pressure bleeder from an old garden sprayer and the lid from a old clutch reservoir, I had new master cylinder,new abs pump and all new brake lines so system was completely dry, so easy I had solid pedal on the first attempt
Just pumped it up and opened the nipples in turn....

Only issue was ABS warning light and some checking turns out the relay was kaput

Excellent. New master is ordered so should just be a case of bolt on and bleed then. Its definitely been burning some brake fluid through the servo as i've been getting a bit of white smoke. Hopefully this fixes all!



Cheers for that! Nah just bought a brand new master cylinder. Not worth buying a kit or a refurb one really. Thanks for the offer but I have heaps of pipe and fittings I can 'borrow' from work



Excellent. I already bled them with a gunson eezi bleed and its an ace tool! I have copper brake lines so i'm sorted in that respect. Really hoping the master just sorts everything out then I can get back on the road!