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Discussion Starter · #1 ·
ok, i'm having some PIA brake issues. my pedal has WAY to much travel in it. when i first did my axle swap (3/4 ton dodge) i swapped out the MC for one off a 80's bronco, i had good breaks for months then they started to slowly get worse, adjusting the rear drums helped but after a while that stopped helping.
i have replaced the booster with a new stock YJ another reman ford MC and now i am on a new ford MC. replaced everything in the drums ( wheel cylinders hardware shoes) and bleed the sh*t out of the brakes and MC. still the pedal goes almost all the way to the floor, Oh yea i adjusted the pushrod in the booster to and pulled the oring in the valve.
only thing left is the combination valve. i know with the 3/4 ton brakes and stock type master and booster i won't have great brakes but i want what i had when i first did the swap.
SOOO can a combo valve go bad? i have thought about useing a adjustable prop valve but i'd rather not re run all those brake lines when i had decent brakes 3 months ago.
i just don't want to waste 100 bucks at the dealer for a new stock valve.
thanks for any input
 

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Assuming you used the Chevy/Jeep style brake proprtioning valve, they can crap out on you, but first, thet have a safety mechanisim built into them that sometime needs reset. on one end there should be a little rubber cap, under that is about a 1/8th inch pin sticking out, depress this while someone pumps the brakes, this resets the valve. *note, on some valves you have to pull out on this with a pair of needle nose. it will only move about a 1/8-1/4 inch either way. this is what ensures you have some brakes on the rig should you blow a front or rear line, it switches all pressure to the other end of the rig. if this dont fix it then its proball crap. look to spend about 90 for a new one:(

Good luck
 

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Discussion Starter · #3 ·
yes i am useinga stock 89 YJ combo valve, but theres no pin under the rubber cap, a few months ago i unscrewed that nut that the cap is on and pulled out the oring that was inside it,
last night i replaced the master Again and bench bleed the hell out of it and the rest of the system once it was on, now only the front drivers side tire will lock up after pumping the brakes 3-5 times real fast, i have braided flex lines on the drivers and rear but the pass side is a old stock YJ one so i'm guessing it swelling is stopping the pass tire from locking, i am replaceing it today, but the rear doesn't seem to grab at all, and i adjusted the brakes till they dragged alot and still nothing, a new valve from jeep is 66 bucks so i guess its time to try that.
any other ideas
thanks
 

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Discussion Starter · #4 ·
ok the new brake line is on and it feels a little better but the rears still arn't doing shit so i'm guessing it has to the the combo valve,
come on people someone has to have had one of these things go bad, what were the symptoms
 

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You actually created your entire problem when you removed that o-ring. You are now sending nearly full volume and pressure to the rear. You have eliminated almost all of the proportioning. That modification is only for people that have installed rear disc brakes. Put that o-ring back in or, get a new proportioning valve, or you will continue to blow out wheel cylinders.

Ben
 

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Discussion Starter · #6 ·
no my wheel cylinders are and have been fine, i noticed a little seepage coming from one so i replaced them both, i figured with the D60 wheel cylinders i needed as much fluid to get back there as possible, and i pulled the o ring months ago and i just strted haveing problems maybe a month ago.
 
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