no fluid?

[19674x4]

Ok i started to bleed my brakes and when i was pumping the pedal i got no fluid at all, even after pumping or like 5 min. I just put a new master cylinder in(yes i bench bled it) so i unhooked the brake lines from it and tried pumping again to no avail, what did i do wrong

[fordman]

assuming there is fluid in the resivor. maybe it just neeeds more pumping. maybe all the air didn't get worked out. or the mc is bad and going into the booster.

[Leadfoot]

assuming that you bench bleed the master cylinder proper my bet is you tripped the prop valve, next time before you start pumping the brake pedal try to gravity bleed the brakes first it normally speeds things up and helps you not ta trip the prop valve.

also faulty reman master cylinders are common so you might just have grabbed a bad one.

[19674x4]

the master cylinder is brand new. it has manual brakes. whats the prop valve?

[fordman]

if you have disc brakes you would have put a proportioning valve in when you put the discs on. if you have drum brakes you have a distrbution block.

[thedel]

prop valve is proportioning valve, it distributes appropriate pressure to the front and rear brakes. If your not getting fluid directly from the master cylinder when the lines are off as you depress the pedal, then you have a problem with the new master cylinder or the linkage that connects the manual master cylinder to the brake pedal

[bluef250]

Does petal get firm when pumping. I so you might check to make sure the lines are clear. This may require loosening and/or disassembling connections at selected spots as you go away from master cylinder.

[19674x4]

now that you say proportioning valve i understand, i just did not undestand the abreviation( i am still young). I have a distrobution block. I have narrowed the problem down to the master cylinder so this weekend i will re-build it.

[Leadfoot]

ok what I'm talking about is the valve on the frame it on all the trucks after 1966 that have a dual master. Ie single or fruit jar masters don't have them. what they do is cut off the line that has the least pressure and turn on a warning light. Ie prop valve or slide valve. they do not monitor brakes front or back to stop lock up. they are a safety item so if one line front or back leaks the other still can work. and the only difference in drum ta disk is the diameter of the valve. because in disk there is more fluid flow required for the disk brake caliper..

Also if you are bleeding your brakes often if you push the brake pedal down to far you risk wrecking the master cylinder, by cutting the cups or seals when you hit build up or rust. put in simple words don't bottom a master cylinder when bleeding.

And a little tip when you install your new master put some sili glide lube(brake slide grease) in the bore it will seal out moisture and make them last about 4 times longer.

[19674x4]

got er done. the little ring that goes in the notch on the piston was to far back so it wouldn't allow the ports to open. I even was able to bleed all the brakes.