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How do you adjust the proportioning valve?**SOLVED**

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us74k5

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I swapped my 14ff to a disc brake setup using this setup http://cgi.ebay.com/ebaymotors/14-B...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

I know other people have used it with no problems. After bench bleeding my MC and bleeding the brakes for much longer than I had to, I ensured that all of the air was out of the lines. My front brakes stop really well, but I am getting zero braking from the rear whatsoever. You know how the rotors tend to get surface rust on them, but where the pads clamp down its nice and clean? It is like that on the front, but on the rear rotor's there is no sign that the pads are clamping down at all. Surface rust that I can wipe away with my finger. Anyone know what could be causing this, before I tear the whole thing apart?
 
Well, assuming that you were able to bleed them, in other words fluid squirted out when you loosened the bleeders with someone pressing on the brake pedal, that means that there is no blockage or a bad master cylinder.
The next most common problem is mounting the calipers upside down. Actually swapped left to right. If so the bleeders are on the bottom. Which means no matter how much you bleed them on the truck, you will have a big air bubble on top.
From what I have heard, you can either swap sides and get the bleeder on top, or take them off, block the piston and bleed them with the bleeder on top then put them back on.
That sounds like as much trouble as just swapping them.

Either way, if the fluid is being pumped to the calipers, either the pistons are stuck, possible in some from a junkyard, or there is an air bubble somewhere.

J.
 
I am certain that the calipers are on correctly. I pumped about 6 ounces of fluid after the bubbles stopped, just to ensure that there were no air bubbles. And yes I kept the MC full. Also the calipers were brand new, not junk yard stuff. Can anyone think of any other reason why they still are not working?
 
And the bleeder screws are on the top of the calipers, right? And the fluid squirted when you pressed on the brakes with the bleeder open.
Then something should move when you press the pedal.
But if the fluid did not squirt, just flowed, then you need to check the master cylinder and the proportioning valve.
I don't remember if the master cylinder needs to be changed or not, but you should get some movement of the pistons.

J.
 
Yep, they squirted. I even hooked up a plastic hose to them, with one of those bleeder kits. Filled that bottle up 4 times per caliper.
 
You need to bleed the proportionong valve as well if you didn't already. That had me stumped for a while.
 
but I have pressure in the rear brakes... I mean, fluid comes out of the bleeder valve when I press the pedal down just like it does in the front brakes. There is zero clamping going on at those rear brakes, do you still think that could be the prop valve?
 
are the pistons moving at all yet when applying the brakes on the rear calipers? If you're getting fluid flow back there and they're not soft feeling I'd get new calipers, something is definitely wrong.
 
If you opened up and bled the master cylinder, the valve has to be bled after that. The fluid will pump right past all the air in the valve and you get nowhere. I know from experience.

Mine had a bleeder on the front of it and I had to crack open each outlet fitting while pumping the pedal like you do at the calipers.
 
Ok, the prop valve is the one that is mounted on my front cross member i do believe. If that is the thing that could be stopping my rear brakes from working, how do I go about adjusting it?
 
i don't think there is an adjustment on that valve. there is supposed to be a button on one side you can push to reset it. i tried to reset my buddies valve on his buggy, and it would not move. he's having trouble with the front calipers locking up, and i thought that would solve his problem. it didn't
 
Am I wrong to assume that if i have pressurized oil coming out of the bleeder valves on these rear calipers, that it is not an issue with fluid?
 
us74k5 said:
Ok, the prop valve is the one that is mounted on my front cross member i do believe.
Click to expand...

yes, that's the one. You have to bleed it just like the master cylinder. You can screw on special fitting on the outputs that send fluid back to the master resouvior or you just crack open each line fitting as someone is pressing down on the pedal and then close it before they take their foot off. Then rebleed all four wheels.
 
us74k5 said:
Am I wrong to assume that if i have pressurized oil coming out of the bleeder valves on these rear calipers, that it is not an issue with fluid?
Click to expand...

maybe that's your problem, using oil instead of brake fluid?? :haha:

your calipers might be froze up. new ones are cheap enough, go get 2 new ones.
 
are you actually driving the truck to see if they are working? does this get driven on the street? if not, you can just bypass the prop. valve and run a direct line to the rear brakes. be sure to plug off the inlets and outlets for the brakes in the prop valve.
 
Yeah I have been driving the truck. The front brakes are the only things working. I am not getting any stopping power from the rear whatsoever. And yeah it drives on the street, but only to the trail.
 
ya. i screwed around with my brakes for a while when i put disks on the 14bff. i did end up buying a bigger master cylinder, that has a bigger diameter plunger, to push more fluid.
 
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