Alright my brakes are making me crazy. I did the rear 3" in the back a couple months ago and put new pads and rotors on the front. After many fading problems I decided in my infinite wisdom I'd do the master cylinder. Well the master wasn't the problem and now I'm extremely frustrated.
I benched the master before I installed it then re-bled the system using all new DOT4 fluid.
Here's the symptoms:
I step on the brakes and the truck grabs right away and slows her down beautifully but the more I hold the pedal the more it falls on the floor until I'm completely stopped and it's down all the way. Then the ABS and E-brake lights come on like it's got no rear brake pressure anymore. I lift up off the pedal and it creeps back (a little slower than edit I'm used to) and then I jump on her again and she does the same thing. Now after driving like this for a week or so it's getting really bad to the point where it felt like I had no rear brakes whatsoever. I pulled the lid off the master and lone behold she's empty on the rear circuit (front tank of reservoir). I just got finished bleeding it again and still the same problem but after I drove it and came back I noticed that there's fluid shooting out of the lid of the reservoir and dripping down the booster onto the frame rail. Yes I have the lid gasket in properly in case you were gonna ask. What the heck is going on here? Can anyone shine some light on this for me? I'm thinkin' distribution block now but I've never ever had one go on any vehicle I have ever owned - and I've owned a ton of cars.
Thanks in advance.
-Mike

 

Was this Master Cylinder a POS reman or a brand spankin new one?

 

Other than air or a "POS" replacement cylinder, the only thing I've run across, is the "by-pass pin" (for lack of proper term) on the end of the dist. valve, under the rubber cap. Sometimes air will trip it, sending fluid pressure to the front, causing the MC to bypass and spit up. See if it will push back in at all.

 

Will do first thing in the AM. Talking to some mechanic er... "technician" friends of mine they told me the rear brakes just need to be adjusted properly (apparently the "self adjusters" bite) which may be causing excess pressure in my master cylinder causing it to puke out all it's goodies all over the place. I fail to see the logic but whatever. I'll start at this said pin for now.
Time for bed now though.
Cheers
-Mike

 

Oohhh your gonna love inboard brake service work, can't wait to hear from you again! Hehe... It is likely the most neglected maintenance on the truck. But I doubt their so out of adjustment that they are forcing the fluid out of the MC, I bet you have a leaking wheel cylinder if anything. Or like I said, a Pile Of Crap reman Master Cylinder.

 

So it appears I have got 'er beat. All I did was adjust the rears and bam! Now the thing stops better than it ever has in it's life. Maybe for the hell of it I'll put the factory master back on it seeing as there wasn't anything wrong with it in the first place..

 

i had the same issue in my truck. only the fronts work. we tried bleeding it and stuff. and replacing the rears but we never found a fix. it just got to the point where we lived with it. fronts work great though. backs spins in winter so we just pop it in neutral lol. needless to say its not on the road much in the winter.

 

Alright I have FINALLY actually got the whole rear-brake problem figured out after relentlessly beating my head against the wall. Yes I had more issues after adjusting the rears.

The RWAL solenoid valve has laid an egg. I had my dad look at it (who's been a Ford mechanic for 30+ years) and figured it out in about 2 minutes. Apparently the solenoid valve is not releasing pressure properly and is sending the rear wheel brake pressure back up to the master cylinder. He said it's a very common problem in older fords with RWAL brakes. We popped the top off the cylinder, pumped up the brakes and let off. After about 15-30 seconds (more or less) it puked up the pressure and a little geyser shot up from the rear circuit and spewed brake fluid all over the engine compartment.

Instead of replacing the whole valve for $300 plus I'm just gonna undo the in/out lines, cut the ends off, do some creative line-bending, install a brass compression union in it's place and bypass it completely. I have never needed to use the RWAL brakes before and considering the recent brake work (1-ton's in the rear) I'm pretty sure I never will need to. I do know how to drive and don't cruise around like an idiot so I'm sure I'll be fine - not to mention my truck's not a heap and still drives like a champ.

Just thought I'd throw that out there in case anyone else is having the same problems.

 

see if your dad has a flaring tool for brakes. hate to see you use a compression fitting. thanks for passing on the cure.