Originally Posted by cobalt327
The last M/C I installed on my '80 Malibu used that method. Plugs were used to completely stop flow from the outlet ports, then the piston was depressed gently and not fully to the rear stop to expel air from the reservoir feed ports in the bottom of the reservoirs.
But the way you had yours plumbed to bench bleed above was correct, as long as it was leak-free and tight.
Is there a chance that you weren't pushing hard enough on the piston to overcome the resistance of the larger spring that separates the front and rear valves?
Hi 327. Yes the connections were good without leaks. So i have bench bled it again, but plugged this time. The travel i measured was 11/4 inches until it bottoms out. I have fitted it back on to the power booster and i have purchased a vacuum brake bleeding kit to try and suck the possible air lock out of the rear chamber of the master. Like you said,i am not certain that the secondary spring is compressing enough to force fluid out. If this vacuum pump does not work then i will find a piece of 1 inch hard plastic conduit , cut a slot out of the side and set both pistons in it so i can see how far the rear piston is moving when i push the 1 1/4 on the front piston. From the section drawings i have found on tandem master cylinders the seal has to be behind the filling port at rest and then travel past it to compress the fluid.
Cant let it beat me. No joy from Cal Mustang /LA where it was purchased originally. The receipt shows disc brake conversion kit. i assumed the master was the correct one with the kit.