No fluid coming thru bleeder valve

[rootbeer]

Just replaced booster an MC, wheel cyl and rear shoes.
Bled both rear and pass front ok but cannot get any fluid to flow from
front driver side even when I remove bleeder valve completely?!
It's a power disc front/ rear drum on 86 C20.
Any ideas on possible cause or checks I can run ?
Many thanks.

 

[89Suburban]

Sounds like a clogged brake hose to me.

 

[HotRodPC]

Yep, could be a collapsed rubber line. Although, when that happens, they'll usually let fluid thru, but not back up. I guess it's possible the line collapsed and the fluid tried to come back up it pulled the inards up into a clog. It's going to be either that or a failure at the proportioning valve which could be if the valve got hung up. But that is rare. Not that it doesn't happen, but it just rare.

 

[Driver4r]

Dumb question, but did you run the bowl out of brake fluid?

 

[rootbeer]

Dumb question, but did you run the bowl out of brake fluid?

No, but it's often dumb obvious things that're the problem.
I found a lot of muck in the fluid as I was flushing it and the rear cyl seals were pretty shot so it maybe something foreign in the system. I got new lines for the front as a precaution so that's the next step. Prob should only be in flex part of hose tho right And not hard lines from MC? I'll keep you posted.

 

[89Suburban]

Yah, the soft lines can swell up inside and block the line, but usually you have warning signs of that like pulling brakes or lack of braking. Swims just went through hell with his brakes, did all kinds of stuff and it turned out to be a clogged rear rubber line. You can always just crack the line off and see if fluid pushes out of the hard line, that will tell you for sure if it is the hose or not or even a clog in the caliper bleed port itself. Just start at the caliper and go up the line, process of elimination mind set. Don't blow money on parts until you find the problem.

 

[Chevyguy]

No, but it's often dumb obvious things that're the problem.
I found a lot of muck in the fluid as I was flushing it and the rear cyl seals were pretty shot so it maybe something foreign in the system. I got new lines for the front as a precaution so that's the next step. Prob should only be in flex part of hose tho right And not hard lines from MC? I'll keep you posted.

Gravity bleed em after you replace the lines, and then only press the brake pedal once when you bleed them the normal way. After gravity bleeding you should have a pretty good pedal. Only pressing the brake pedal once cuts down on the chance of turning one air bubble into ten air bubbles, so don't pump the pedal five times and then hold. The pedal will get higher and firmer each time you bleed the lines.

Clayton

 

[Magnum44357]

I had the same issue with my truck last year. rear driver side cylinder wouldn't push any fluids. I too replaced the cylinders and master cylinder. It turned out to be little bits of rust and dirt. I assume it was from my old master cylinder because of how bad of shape it was in. I had a friend pump the brake over and over while i bled. because I thought it was air in the system. like I said it turned out to be just gunk, once it gave way, it shot me in the face hahaha. because of how it came out, I almost think by pumping the break it slowly worked down the line untill it broke up or something. Now it works flawlessly