Brake Combo/Prop Valve

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firebane

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So I have now installed a new master cylinder, brake booster, 4 new soft lines, 2 new hard lines and my brakes haven't changed. I can get the fronts to stop but nothing I do will get the rears to engage at all.

I have been looking at some information and a lot of places talk about resetting the combo/prop valve and this has me left with quite a few questions and hopefully someone can fill in some of the blanks.

1) Does the button on the combo/prop valve need to be pushed in when doing brakes?

2) I heard of a little pin on the comb/prop valve behind the rubber boot. I have removed this rubber boot but see no pin. Instead I see a silver button that I can push in but just comes back out. Should this pin be visible when the combo/prop valves is functioning correctly?

3) I have built up pressure in the system then slammed on the pedal to try and reset the combo/prop valve but that didn't seem to do anything either.

4) I KNOW for a fact that the rear brakes probably haven't worked in a long time because either a) someone replaced the pads or b) the pads still have so much meat left on them that they look brand new.

Nothing I've done so far allows me to properly bleed the rear brakes. I've had my girlfriend push the pedal down and I crack the bleeder screw but nothing comes out.
 

firebane

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Well the thing is the pin isn't protruding out. Its flush with the silver button which to me means its not set right.

I am probably just going to pick up a new since well everything else is new for brakes on the damn truck.
 

1low4x4

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That's how mine was. Flush. For lack of a better idea I replaced it and it fixed it
 

firebane

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That's how mine was. Flush. For lack of a better idea I replaced it and it fixed it

When you replaced it and bled your brakes did you have to do anything to the combo/prop valve or just install and bleed?
 

1low4x4

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Is your wire to the combo valve hooked up? If so you should have a red brake light on in the cluster indicating a problem. When flow is shut off to either front or back it trips that light
 

1low4x4

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When you replaced it and bled your brakes did you have to do anything to the combo/prop valve or just install and bleed?

Just install and bleed as normal. It was pretty damn easy, just soak them brake lines on the old combo valve with wd40 for awhile and use a line wrench to get them off
 

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