Proportioning Valve?

[noahsdad86]

My brake light has been on for like 4 years now and I am finally in the mood to go through the truck and fix all the little odds and ends that are wrong. After some trouble shooting I determined the source of the light was due to the proportioning valve. I pulled the connector from the valve and the light goes out. Brakes work fine, always have, light still works for e brake and stuff, but this part on bronco graveyard is like 165 bucks. Can these be rebuilt, is it even something i should worry about or would I be stopping better with a good one, or are there any cheap ones?

 

[bidibronco]

Sounds like it's due time to take a trip to the ol' junk yard...

 

[Roadkill]

Maybe it's the switch? If your brakes are working fine, that could be the case. LMC Truck has the switch for $19.95 as apposed to the $199.95 for the valve. I don't normally advocate part swapping in lue of troubleshooting, but $20 is not a whole lot of money and you're brakes appear to be working fine for the last four years.

 

[nick c.]

My brake light has been on for like 4 years now and I am finally in the mood to go through the truck and fix all the little odds and ends that are wrong. After some trouble shooting I determined the source of the light was due to the proportioning valve. I pulled the connector from the valve and the light goes out. Brakes work fine, always have, light still works for e brake and stuff, but this part on bronco graveyard is like 165 bucks. Can these be rebuilt, is it even something i should worry about or would I be stopping better with a good one, or are there any cheap ones?

 

[nick c.]

Like Roadkill stated, 20 bucks isn't much to spend for a fix. Could be the switch but those vavles are also known for going bad. Since the valve controls braking to weight transfer for rear brakes, it's not really something that you want to just "unplug and call it fixed". Try the switch first and go from there, if that doesn't fix the problem then unfortunetly it's time for more digging, which we all know and love.

 

[miesk5]

shuttle valve in the proportioning block may have moved.

Check the entire system for leaks, check the adjustment on the back brakes, then bleed the system.

Once you have completely bled the system follow the instructions in the Haynes manual on how to recenter the shuttle valve. by Gacknar

A defective proportioning valve or one that is not adjusted properly can also upset brake balance. So if the rear brakes on a vehicle seem to be overly aggressive (too much pressure to the rear brakes), or the vehicle seems to take too long to stop (not enough pressure to the rear brakes), the problem may be a bad proportioning valve.

 

[bidibronco]

I have a question about this as well, at least I think it may have something to do with this. When I hit my brakes, not to the point of lock up but when I'm getting on them good, my rear brakes will lock up but let my front kind of shimmy, like my rear brakes don't have abs but my front do. Anyone know why this may be?

 

[miesk5]

I have a question about this as well, at least I think it may have something to do with this. When I hit my brakes, not to the point of lock up but when I'm getting on them good, my rear brakes will lock up but let my front kind of shimmy, like my rear brakes don't have abs but my front do. Anyone know why this may be?

Finally found it!

CAUSES for Rear Brakes Lock Up Before The Front

Not enough proportioning to the front brakes and off of the rear brakes.

REPAIR

Add an adjustable proportioning valve to the rear line to reduce the rear brakes more.