Brake problem

[macawpat]

I have a 1976 Dodge M880. My brakes were done several months ago and worked perfectly up untill this week. What I am experiancing is that when I apply the brakes only one tire is locking up and stopping the truck while the other three keep keep rolling. I have never seen this and have no idea what it could be. Booster is fine and the master is fairly new. Any help would be extremely appreciated. Thanks

 

[gimpyrobb]

Time to pull apart the wheel cyls that aren't working, or it could be the tubing is crimped. Couldn't find the dodge section?

 

[Recovry4x4]

OK, moved i to the correct forum. You need to determine if you have 3 wheels not braking or one wheel locking up. Odds are better that it's just one wheel. Since both rear wheels are tee'd off a single line, problems there would be limited to wheel cylinders or rubber hoses. Combination valve could also have an effect on things. Which wheel is locking up?

 

[macawpat]

Its the passenger front that locks up when nailing the brakes. A friend told me there is some type of valve after the lines come out of the master and then go to the different wheels. Something about a control pin that may be stuck ?

 

[Recovry4x4]

That is called a combination valve. It does 3 functions. Proportioning valve, metering valve and pressure differential valve. The pressure differential valve being stuck could cause you to have only front or rear brakes but I can't imagine it causing only one wheel to brake. Do a little investigating into the combination valve. Is the brake light on? If the pressure differential valve is thrown, you should have brake warning light activated.

 

[macawpat]

Well due to the many people who had the truck before me it no longer has a brake light. All the brakes were working perfectly untill one morning. They were redone and a short time ago but close as I can figure it is just the one passenger front that is working now. But that is what my friend thought it was the combination valve.

 

[Recovry4x4]

Do some google research on the combination valve. You will see how it works and hpw to reset the pressure diff valve and see if that fixes the issue.

 

[macawpat]

Will do thanks and I will wait on that weather

 

[Recovry4x4]

LOL, You can have all of that 95x95 stuff we have.

 

[macawpat]

Ok thanks and tell all them gators I said hello. Happy thanksgiving and thank you for the help.