Proportioning valve ?
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Proportioning valve ?
Had some brake issues. Replaced MC & vacuum booster. When bleeding the brakes I noticed the pin on Prop. valve is sticking out. The brake light works when I start the truck but doesnt stay on like theres a problem. I have 2 other valves in garage so I looked at them. 1 pin moves by hand the other doesnt move even with visegrips. Which one is right? And does the one thats on truck just need re-centered by turning key to on and pressing the pedal?
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Joined: Nov 2007
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From: Denver Metro Area, CO
See if THIS THREAD helps you; it's from 80-86 but for stuff like this, it shouldn't matter.
My thoughts are the pin should be able to move, you might take stuff apart and clean it out.
My thoughts are the pin should be able to move, you might take stuff apart and clean it out.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The pin is supposed to move. If you can't move it, then the front metering valve is stuck. When you bleed the brakes, you pull this pin out and hold it there with a small clip while you bleed the fronts, then close it back up. This bypasses the metering valve to make sure air goes through.
What were the issues?
This is what is supposed to happen - the light should briefly come on when you turn the key all the way to START, but is supposed to shut off when the key returns to RUN. What is the issue? Are you saying you're having a problem, but the light doesn't come on to indicate that there's a problem? We can't help you if you don't tell us what the actual problem is.
You're talking about the differential valve. This is in the center of the assembly, inside. With all four bleeders closed, slowly press the pedal down then all the way back up. The only reason to have the key on is to see when the light goes off.
What were the issues?
You're talking about the differential valve. This is in the center of the assembly, inside. With all four bleeders closed, slowly press the pedal down then all the way back up. The only reason to have the key on is to see when the light goes off.
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The 1st issue was I needed to replace the MC & vacuum booster. Thats done. The 2nd issue was the pin not moving. What my question is, should I be able to move the pin with my fingers or should there be resistance? The one on the truck cant be moved. With the 2 I have off the truck, 1 moves freely when I pull it out and the other one doesnt. I think Ill just order a new brass block valve and be done with it.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
As I said in my previous post, the pin is supposed to move. It should not take much force at all to pull it out.
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