69gaugeman

I don't know for sure , but under vacuum (that's what the mighty vac does, right?) You may be pulling air into the system.

A pressure bleeder is by far the best way to do this. If you are getting fluid out of all calipers, when you press on the brake pedal does it still move the fluid in the resevoir up and down?

Can you bleed the brakes normally with the pedal?

It really sounds like a master cylinder seal between the pistons has let go. (imo fwiw)

ceedee

i believe you're right , rod.
it seems to be pulling air in the system somwhere. what i believe is, that the air enters at the mastercylinder. i din't know but in my opinion,even if the cylinder is toast internally it would still suck the air out. unless there is a passage somewhere.
yes the fuild still goes down when i press the pedal ,and the rises slowly to the first mark.

now , it's the q of going with a used master, for cheap.
or a rebuild one for over 100 (with core charge)

ceedee

fabio, does that offer for the power bleeder still stand?
don will get one this friday and lives a lot closer.
but if i knew already what's up before having to buy a new master cyl or not

Jim M.

Lets re-cap everything:
1. No brake problems originally.
2. Because of a broken bolt you changed BOTH front calipers. During the changover you pushed one of the caliper pistons in to gain additional access. (This won't harm anything, including the master cylinder, unless you now have a leak.) Did you allow the fluid to drain out while you had the calipers off? If not and the master cylinder didn't drain to empty I doubt the problem is the master.
3. Also while changing the calipers you changed the hoses (so you did mess with the lines.) With new hoses and new (?) calipers you start out with a ton of air in the system, not to mention the air that got in when the old hoses were removed and the hard lines drained.
4. While bleeding with a mityvac you get lots of air. Ten (10) bottles of Mityvac fluid is not nearly enough. Using a Mityvac, it can be difficult to avoid pulling air through the bleeder hose/port connection. This can be minimized by putting a dab of grease on the bleeder port before installing the hose. Instead use the power bleeder or get a buddy to depress the brakes while someone else bleeds the calipers. PUMP, PUMP, PUMP AND HOLD and NOW OPEN BLEEDER PORT UNTIL PEDAL GOES TO THE FLOOR. Keep doing this until NO air comes out with the fluid.

Now, if the master did get drained to empty then everything above is a moot point and it may in fact be a master, but why did the replacement master fail after one day? ANSWER: because it wasn't bled properly the first time!

Jim Mayzurk
93 GTS 5-spd

ceedee

ok this time i tried a different approach
i took one of the flex hoses from the useless mity-vac and connected it to the little collection bottle that came with the useless mity-vac. i filled it with brake fluid. i set the bottle in a little container, so that when the bottle would be full the stuff wouldn't just runn all over the floor. then i connected that assembly to the caliper, just the way i connected it the last 500million times. i then set the bottle and all on a bucket (!), so that it was a little ihgher than the caliper, but below the brake-fluid reservoir. then after only 2 hours of pumping i had pressure on the line.
now i would like to address a few words of appreciation to all of you.
scott, stan, fabio, don, angel, heinrich, rod and jim. without you all and your great tips and help i would have given up after the first day of pumping. i really am very thankful for your time and efforts specially on new years eve.
and i hope that this thread and my little write up will help someone else in need.
now if you got no pressure and just spunge bob in your lines, then don't give up try the way with the little bottle and fill it with brake fluid.
again

69gaugeman

Glad to see you got it sorted out? (you never said if you did or not). But if you did it is how this whole thing works. Enthusiasts helping enthusiasts.

No thanks needed, you did all the work.

Fabio421

Congrats. Why do the brakes have to be so difficult to bleed on these cars? It's B$##@@^^%.

ceedee

x2 that

heinrich

I'm glad you can once again stop your Porsche, CeeDee