front brakes won't bleed

[cuda hunter]

71 chrysler newport custom
front disc's rear drums.
pedal goes to floor pretty much. It has some resistence.

I gravity bled the rear lines, worked great. Ran clear after about 3 M/C's worth.
I opened up the front lines, separately, and I get no drips at all.
Worked my way up from there, no drips until I got to the M/C.
Cleaned the reservoir in the M/C, fluid would come out of the bottom of the M/C when pressing the brake pedal. Not a lot, drip, drip, drip.
All put back together.
Am I correct to assume that my proportioning valve is not working properly?
Is the little dick on the front of the prop valve a push in type clearing button? What is that little dick thingy?

Otherwise, suggestions please as to how to proceed on getting the front brakes to work.

 

[mopar440]

That's the centering valve, probably bad, use something to hold it in, then bleed

 

[cuda hunter]

Ok. thanks. I tried to press it in but it was pretty solid so I didn't push hard enough to break it. Apparently I need to push harder. I'll try that.

 

[mopar440]

Yes, probably use c clamp

 

[cuda hunter]

Wow. that much pressure.
Am I expecting it to go in 1/8" or more? 1/4"?

 

[mopar440]

Wow. that much pressure.
Am I expecting it to go in 1/8" or more? 1/4"?

Not sure exactly on this one, but probably around a 1/4, be gentle, shouldn't be hard

 

[cuda hunter]

Out of about 25 C clamps I can't seem to get one to fit into there.
Hmmm. This is why I am not a PRO mechanic. Just a hobbiest.

 

[cuda hunter]

So, if I can't get it to push in while on the car, Is it as easy as removing the Proportioning Valve, Then removing the centering valve on the bench, cleaning it, installing the centering valve and reinstalling the proportioning valve?
Gravity bleeding the system again.

I get removing the PV is a PITA.

 

[Davea Lux]

If you are dripping fluid out of the bottom of the master cylinder, either one of the two brake lines is not properly seated or the master cylinder has bad rubber cups inside and fluid is running out the back of it and dripping from the bottom. If the front brake line is not seated or the front piston is bad, it will suck air every time the pedal is released and the system will not bleed. The centering valve also appears to be leaking given the wetness around the rubber on the front of it. There are o-rings inside of most of them and yours may have failed.

Dave

 

[cuda hunter]

The cap on the M/C was expanded by 1/4 of it's size and it was leaking from the actual top of the M/C.
I've replaced the seal on the M/C and a new cap.
The brakes have worked for some time on the car and just went soft a few days ago.
Brake light in the interior dash is on.

 

[cuda hunter]

It was not dripping fluid with exception of spilling out the back of the M/C.
That I could tell anyway.

 

[cuda hunter]

I have been messing with the system and actually caused the wetness on the rubber centering valve.

 

[cuda hunter]

Better picture anyway.

 

[Davea Lux]

Try cracking the bleeder screw on one of the rear wheel cylinders. That will release hydraulic lock on the centering valve and it should push back that way. Bleed the fronts and then try bleeding the rears.

Dave

 

[cuda hunter]

Ok, will do.

Nope, didn't work. Tried cracking both sides.

 

[Davea Lux]

In that case, do you have a bench bleeding kit, that is the short hoses that go from the two output lines back into the master cylinder fluid pits? If so, disconnect the front line and purge the air from the front brake piston. This should give you enough pressure to force the centering valve back where it belongs so you can complete the bleeding process.

Dave

 

[mopar440]

You cracked the rears and the valve wouldn't move?

Try wrapping " carefully" on the side of the valve, when it's being pushed in, should move

 

[cuda hunter]

I tried tapping it already.
All the bleeders and ends of the lines I opened came loose very easily. I sprayed em once with blaster but didn't give em much time. They loosened like they are supposed to.
Seems odd that the Centering valve would be the only thing to stick.

 

[cuda hunter]

The valve would not push in when either of the rear bleeders were open and dripping.

 

[cuda hunter]

In that case, do you have a bench bleeding kit, that is the short hoses that go from the two output lines back into the master cylinder fluid pits? If so, disconnect the front line and purge the air from the front brake piston. This should give you enough pressure to force the centering valve back where it belongs so you can complete the bleeding process.

Dave

I might have that tool. I'll have to look. I'll try that next if I have the tool. If not I'll go buy it.