Proportioning Vlave?

[Case500D]

I think working on my truck brakes is becoming a hobby. I can't get the brake/abs warning lights to go off now. When I stop, it feels like the front brakes just seems to "slide", almost like the front brake pads are glazed over. However, I do know that the front brake pads are fine, the rear 3" brakes are adjusted up correctly. The vaccuum booster and master cylinder are new. I have bled the brakes out twice. After reading the service manual, I am wondering if it could be my proportioning valve? Or do you think there could be an air bubble trapped in it? The truck does stop decent, but not as good as it used to. The front brakes do not shake or wobble. Also, in the mornings when I hit the brakes for the first time, they really grab hard. Sometimes the front wheels will lock up. Maybe I just need to unhook the ABS stuff. Thanks for the help and ideas.



Jeremy

 

[McGivern]

rear lock up

Jeremy,

I think the brake system is just shady. Ever since I put 1 ton brakes on the back the rears will lock up if I get on them hard. I too am contemplating disconnecting the ABS. Only suggestion I have is didi you bleed the petcock at the proportioning valve above the rear axle when you changed brakes? I didn't at first and my brakes sucked until I did.

Mark

 

[Midnite]

I unplugged the RWAL harness at the box behind the glove box and noticed absolutely no difference at all. I'm going to wait until the roads ice up around here and then try it again--maybe I'll see some difference then.



If you're seeing problems on dry pavement though, I would think it's something else.



Mike

 

[Case500D]

Mark,



I did bleed out the RWAL brake valve back on the driver's side frame above the rear axle. I bled it out before the rear brakes. I feel like a putz becuase I can't get these things figured out. They are alright and safe right now, but I know they can be better. Thanks for the help.



Jeremy

 

[Wayno]

Jeremy, I will bet someone will tell you dont do what I am fixing to tell you what I have done to my truck, but I am going to tell you anyway. I took the proportioning valve off of my truck and left it off. My truck has had a right pull problem off and on since I have own it. It drove me nuts. I replace every thing new on the brakes front and rear. I could not get it to stop pulling to the right. Many people tried to tell me what was wrong, even a very good front end man could not figure it out. So one day I took the Proportioning valve off. Now that did not make it quit pulling to the right, but it has a better brake pedal now. You will never guess what was wrong, the right shock was bad. Also I have had bad luck with rebuilt master cylenders, get a brand new one. I have never blead the RWAL brake valve in the many times I have had the brakes apart. Also if you dont know, the front brakes on my D350 or the same as the D150, same caliper,same pads. I think thats the reason they dont stop good. I have never did a brake job on a 4x4. Oh and by the way I took the proportioning valve off the last two trucks that I own, both trailer package trucks,83 D-150 and 76 F-150 and the brakes never gave me any problem at all. I allways use fittings to connect the brake lines back together when I do away with the proportioning valve, I never cut the lines. Take your proportioning valve apart and see if it is full of crud, mighty small holes in that thing.

 

[csnider]

I don't know if you have done this yet ,but before you replace or remove your proportioning valve you might want to replace the brake lines (Flex lines that go from Axle to caliper) these lines deteriorate internaly and cause similar problems . Pulling to the right/left and poor brake performance overall. Just thought I would add that suggestion... ... ..... Chuck