Bleed the brakes

[b5blue]

Is this factory booster? The bolts on my booster are long enough for 2 spacers (?) not that it is correct. The space between M/C and booster is not sealed, my spacer has gaps in it to let brake fluid run out if M/C leaked out the rear. (it did so years ago) I thought you meant could you get air in M/C removing it to check booster rod.

[Belgium R/T -68]

It's a aftermarket "correct" booster/mastercylinder and yes, there is space for 2 retainers/spacers. I did mean in my earlier question
if I could have got air in the mc while pumping with the rod not going all way back.

Per

[b5blue]

It might not have pushed all the air out, bubbles tend to hang around in there and not bleed out. 

[Belgium R/T -68]

I have pedalpressure I bought myself a vacuumbleeder on airpressure and it worked. In between I have found
another 2 small leaks that was difficult to discover because the oil on the floor was only visible after a couple of hours. So the problem was the rod,
which it still is, and air. The mc is now hanging a little bit loose to secure that the rod goes all way back. Question is if some "preload" on the cylinder
is OK? When I let the front wheel spinn and push the pedal it doesn't stop turning, does the pads needs some braking in or do I need the powerassist
for full brakeeffect?

Per

[b5blue]

Power is going to make a huge difference and so will break in. Good job the tiny leaks are just the kind of thing to give you all this grief. 

[lisiecki1]

and with brakes all it takes is a pinhole and you no longer have any....

[Belgium R/T -68]

Back to square 1 again. Now when I bleed the MC in my bench and after bleeding connect the 2 ports you can keep
on pumping, the oil in the big "tank" goes over to the small "tank". If the MC system is closed, shouldn't the piston be stucked?

Per

[b5blue]

??! 

[Belgium R/T -68]

What I mean is that I connect a hose between the 2 ports after bleeding so the system is closed, shouldn't then the piston
be stucked instead of pumping the oil from one side to another?

Per

[Belgium R/T -68]

Now I can't benchbleed the MC for the rearbrakes, when I push the piston it continues to produce air. The frontcircuit just
flush oil without airbubbles so that one is OK. Could it be a burr or other dirt that makes this happen? It is new.

Per

[elacruze]

What I mean is that I connect a hose between the 2 ports after bleeding so the system is closed, shouldn't then the piston
be stucked instead of pumping the oil from one side to another?

Per

Exactly so. Sounds like you have a bad master cylinder. The fluid is bypassing internally. If you pipe together the F & R outlets, you should get pressure and very little/no piston movement.

[b5blue]

I never thought I would say I hope a bad new part is the problem, but it's been the case for me more than one or two times. Is it new re-manufactured or totally new? I've had both come badly made/redone. (I will NOT ever use A-1 Cardone again!) If you bleed and plug the out puts the piston should not move correct? Good luck Per! 

[Belgium R/T -68]

Innerpistons are stucked in innerposition, don't go back on BOTH mastercylinders. I bought them on ebay
2-3 years ago. I have removed the pistons but I don't see any damages. After assembly and bleeding it's still the same problem.
When I put the 2 ports together I can move the piston approx 1/2". Putting it back on the car and the pedal goes to the floor.
When I gravitybleed all 4 wheels oil is coming nicely, when pumping the pedal time after time no oil is visible anywhere so a leak
it can't be aswell. Will order a new mc on monday. So nice wheather this weekend.

Per

[b5blue]

The last 10% of a restoration takes 50% of the work! 

[Belgium R/T -68]

New mastercylinder arrived and is mounted but the result is the same. Now when I start to take a closer look at the calipers which is the next possible source of the problem I notice that the driverside caliper doesn't let oil flow unless a pump
is used, by gravity no oil is coming. What can be wrong on a new caliper?

Per

[b5blue]

AIR BUBBLE! 

[Belgium R/T -68]

Problem solved, see projectthread.

Per

[b5blue]

 

[Belgium R/T -68]

Thought of sharing with you why the rear brakes didn't work. The brakeline front to rear is a
2-piece with a hold off valve on mine. I bought a complete set of brakelines and a new hold-off valve which you only can mount in one way because the inlet and outletside have different threadsize as have the 2 brakelines. Now, the brakelines had the wrong threads on the "nuts" which lead to that the hold-off valve got turned 180° and instead of keeping the pressure at the rear brakes it kept the oil from coming there except for some leakage that I saw when I removed the lines for my troubleshooting. Now I removed the valve inside the brasspiece untill I will
make new brakelines but that means that the system doesn't keep the pressure, will this be a problem?

Per