porprotion brake valve

[bobogidd]

COMPLETE FRONT END SWAP ,NEW BRAKE LINES ,M.C . BR. LINE HOSES,CALIPERS,PADS & WHEEL BEARINGS. USED OLD BOOSTER,PUSH ROD IS ADJUSTED PROPERLY ,MAKES BUBBLES IN M.C UPON TOUCHING PEDAL. REAR BRAKES BLED FINE WITH STEADY PRESSURE FLOW USING BLEED KIT PUMP.FRONT LINES GET FLUID BUT NOT A STEADY FLOW. THE PISTONS ON NEW CALIPERS ARE WORKING & BRAKING SOMEWHAT BUT NOT WELL ENOUGH. BRAKE HOSES ARE CORRECTLY LINED UP WITH HOLES (BRASS MOUNTING BLOCK) . CHECKED ALL THE BRAKE LINES THROUGHOUT FOR A GOOD CONNECTION AFTER BLEEDING BRAKES. FELT LIKE A GOOD PEDAL, SO TOOK HER FOR A SPIN & THE TRUCK STOPPED BUT WAS MAINLY REAR BRAKES.OH YEAH, I REUSED THE BRAKR VALVE FROM DONOR TRUCK. THE REAR BRAKES ALSO KEPT GRABBING ONE TO THE OTHER. BACK TO THE SHOP & FOUND OUT THAT WHEN PRESSURE WAS APPLIED TO BRAKE PEDAL I HAD A LEAK AROUND THE BR. VALVE. RETIGHTENED ALL LINES GOING TO THE BR. VALVE & WENT THROUGH THE WHOLE PROCESS AGAIN ONLY TO DISCOVER THE SAME PROBLEM. PRIOR TO THE NEW M.C THE OLD M.C WAS SEEPING FLUID ALSO, THAT SEEMS TO BE RESOLVED AFTER NEW ONE WAS INSTALLED.AFTER SOME HARD CORE INSPECTION OF THIS PROBLEM, IT SEEMS TO ME ITS (BR. VALVE) LEAKING FROM THE WARNING SWITCH? ANYWAY I PURCHASED A NEW BR. VALVE & WARNING SWITCH,OUCH!! ANY INFO WOULD BE APPRECIATED!

[jor]

MAKES BUBBLES IN M.C UPON TOUCHING PEDAL

I'm not sure about the leak but did you bench bleed the master cylinder before putting it in?
jor

[averagef250]

All caps is really hard to read!

[FORDification]

All caps is really hard to read!

bobogidd: for future messages, please make sure your CAPS LOCK button is off. All caps like that makes a message very hard to read, and makes it seem like you're shouting.

When you replaced the brake lines, did you make sure you used new copper washers between the lines and calipers? They could be sucking in air there if you tried to reuse the existing washers.

Also, are you certain you have a master cylinder designed for use with disc brakes? Installing a drum-brake master cylinder on a disc-brake truck will exhibit the symptoms you're describing about the rear brakes doing most (if not all) of the work.

[ICEMAN6166]

on the m.c.,large reservoir is for front brakes,small one is for rear.

[fordman]

are you sure that the fittings weren't stripied?

[bobogidd]

sorry about the caps,didnt mean to shout. master cylinder is for power disc brakes. yes, i bench bled the m.c each time i went through everything. no threads stripped on line fittings (new) & reinspected. thanks for info on reservoir,got it,ummm not it. yeap , new copper washers everytime. explaination about the bubbles, with lid off the m.c & an assistant, the brake pedal is pushed to check & see if the pw. booster rod length is correct. if it is the fluid in the reservoir will move within 1/2'' of pedal movement, sorry to throw you off, but thanks because i see how that could lead one to believe it could be air in the m.c
welp, this is why i made the post, i still believe its the br.vavle, i will see when it gets here, much thanks!

[averagef250]

I haven't had a leaky proportioning valve before, but I have had several old Ford ones that weren't working right. I pulled them apart to find they were plum full of rusty gunk. Cleaned the guts up, stuffed them back together and worked great. You may be able to open yours up and just replace a couple O-rings inside. There's nothing really to them. I have no idea why proportioning valves are so expensive to buy rebuilt or new. I'd think whoever is rebuilding these things must have a 10,000% markup on thier parts and labor.