Hey fellows. I asked last week about not being able to bleed the front disc brakes on my '69.

I can't get anything through the front bleeders at the wheels, no fluid, no air, nothing... kinda like the front lines are clogged.

I traced it back to the hold-off valve (brand new).

My question is, is there anything specific I should be doing to get fluid through the valve?

The entire system is brand new, including the hold-off valve.

Any ideas? Is is possible to be a bad valve?

I bench bled the master before installing and the rear brakes bled just fine.

I'm stumped.

Thanks

Hold off valve? Proportioning BlockValve. Does that back brakes get fluid/air?

Maybe you have the input connected to the output or something.

Hold off valve? Proportioning BlockValve. Does that back brakes get fluid/air?

Maybe you have the input connected to the output or something.

no, not the proportioning valve on the frame, its the hold-off valve that mounts to the master cylinder that delays the front disc to allow pressure to the rear wheels.

Just the fact that it is a "hold-off" valve makes me wonder if it may be stuck or defective, or if there is some technique that should be used to bleed a system with a hold-off valve?

How hard are you pushing on the pedal?

How hard are you pushing on the pedal?

Well, it pushes very eaisly to the floor. It did harden up a little after bleeding the rear brakes, but it will still go to the floor.

Okay this may be a dumb question but have you bench bled the master cylinder? I know when I installed my 4 wheel disc brakes I tried to use the cylinder with out bench bleeding the MC but I ended up taking it off and doing that and it worked like a charm.

no, not the proportioning valve on the frame, its the hold-off valve that mounts to the master cylinder that delays the front disc to allow pressure to the rear wheels.

Just the fact that it is a "hold-off" valve makes me wonder if it may be stuck or defective, or if there is some technique that should be used to bleed a system with a hold-off valve?

isnt' that pretty much what a proportioning valve does. Guess it is just different on my car, or I am having a brain fart, sorry.


On my 69, I have the master cylinder, then a proportioning valve. Used to have a brass distribution block there, but it was trash kept sucking air in and could never get the system bled. Replaced it with a milidon piece and all is well in the world. It is adjustable too, which I kind of like.

OK, want to check back and post the results.

I'm not sure how what I did to get it working, but, last night I re-bled the master and started over. First thing I did was disconnect the flexible brake line at each front wheel.

I then had my lovely assistant press the brake pedal several times and after bout the 3rd pump I started getting flulid out of both lines.

Re-connected the hoses to the calipers and bled normally.

All is well in the end. :D