New clutch master cyl. needed?

[DMCMW Dave]

So when I crack the bleeder and bleed it out it will stop shooting out the cap? Sorry im just new to the whole fluid shooting out of the cap thing.

No. If it is bad you can bleed it all you want and it won't work.

[stevedmc]

[DMCMW Dave]

[a huge picture]

Unless your master cylinder bore is pitted from long exposure to moisture.

[David T]

Typically if either the master or slave is leaking BOTH of them are corroded and both should be replaced at the same time. Otherwise you are just going to have another problem soon with the clutch and have to bleed it all over again. The hose should also be changed if it is the red plastic one, again, to avoid having to bleed the system multiple times.
David Teitelbaum

[stevedmc]

OP stated in Post #5 that the master cylinder is not leaking. If the cylinder is pitted it will indeed damage the piston seal and leak out the front. If the front is dry, the cylinder most likely is not pitted (at least where the piston seal passes by).

Fluid shooting out the cap is caused by the reservoir shutoff stopper not working. That can be caused by pitting where the stopper seats, but until you remove the piston assembly and look inside the cylinder you won't know. It can also be caused by failure of the stopper (rubber tip), or by failure of the rod that slides inside the piston.

[David T]

Unless you know one of the cylinders was recently replaced, if the system is leaking the best thing to do is to just change BOTH. Especially if the fluid is dark and thick. Yes, sometimes you can clean things up and save them but till you take it all apart, find the parts you need etc, it is just a whole lot easier and faster to replace them. Once you do replace them you can see if it is possible to rebuild the old parts and keep them as spares.
David Teitelbaum

[LEVY]

If it ain't broke, don't fix it!

LEVY

[stevedmc]

Or take the master cylinder off, clean it out with some extra fine grit sandpaper *AROUND THE CIRCUMFERENCE, NOT FRONT TO REAR*, lubricate it with a little brake fluid, stick a new $15 piston assembly in, reinstall the cylinder in the car (hint: weld tabs onto the heads of some 3/8" bolts that will catch on the cylinder and hold the bolts still while you tighten their nuts), bleed the system, and see if that fixes the problem.

[David T]

It's great for you to be so optimistic and try to save everyone some money but in my experience most owners do not flush the brakes (and clutch) often enough. By the time things start leaking and the pedal goes to the floor it takes more than a little sandpaper and $15 worth of parts and a little brake fluid to get the car going again. Not everyone wants to go through taking things out, fixing it, putting it back in and finding it still leaks. Also not everyone is as handy as you are and wants to fix their old parts. It is all they can do to just replace them. IMHO the best advice is to replace the cylinders and if they are so inclined they can have the old stuff rebuilt for spares (or rebuild it themselves). I know this may not make sense to the Bill and Steve team but most owners are not as mechanically inclined as you guys.
David Teitelbaum

[stevedmc]

You act as if just because some owners may be unable to install a replacement master cylinder piston assembly (curious inability if they can replace the master cylinder altogether...) it should not even be mentioned. That kind of thinking leads to $25K DeLoreans. You can not drive 10,000 miles per year with only $500 maintenance by doing wholesale component replacement.

Just for the sake of argument, let's assume the OP has never diagnosed a bad master cylinder piston assembly and replaced it -- should he now be denied the opportunity to learn to do so? If the OP chooses to replace the entire master cylinder, so be it. If he chooses instead to replace the piston assembly alone, he has been provided not only a suitable part number, but also the procedure. That *IS* how inexperienced owners become experienced ones....