Front Break Problem

[kylcrappie]

I've got a 1985 GMC 1ton. I've replaced the Hydro Boost, MC, Front Break lines and both calipers, The peddle want come all the way back up and the front wheels lock up. My wife is just about to sale my truck if I don't get this thing fixed so "PLEASE HELP"

[maxwedge]

Welcome to AF, short on info here, did this happen after you did the work, or is that why all the parts were replaced to begin with?

[kylcrappie]

Let me start at the beginning, My steering was getting hard to turn from a stop. So I replaced the power steering pump, Keep in mind this is a Hydro Boost system. After changing the pump. My Breaks on the front were locking up. I would have to reach down and pull the peddle up to get it to release. So I replaced the Hydro Booster ($180.00)
Well this didn't fix the problem so I replaced the two front lines. I've got good breaks but the peddle want come all the way up. It likes about 1 1/2 inches from the stop and the front breaks are sticking. So I replaced the two front calipers.........Guess what same problem..............I really need to get this fixed. Again the breaks work great, It's just the peddle want come all the way up and the front wheels are tight. Please HELP ! ! ! !

Thanks,
Charles from TN.

[maxwedge]

Disconnect the pedal from the rod, see if there is any binding in just the pedal, you must trace this down on a step by step basis, there is no quick answer here. This is not a problem after the Hydro/MC combination. The calipers could not have caused this, make sure the rod is properly adjusted also if it is adjustable, but this did not occur until after the pump was repalced, correct? It is possible there is some contamination in the p/s system that has affected the hydro boost?

[kylcrappie]

I'm trying to find a Proportioning Valve to fit this truck. (VERY HARD) Someone told me that the valve is my problem. I've got good breaks, It's just that they lock the front wheels up. I've check the peddle and it's very free of travel. Also the spring is good and strong. I can take the MC off and the breaks are still locked up. This has given me a few more gray hairs! ! !

Thanks,
Charles in TN

[maxwedge]

You said the pedal does not return and this holds the brakes on, correct? If you remove the lines from the M/C and the brakes don't release, usually the hoses to calipers are bad.You did not answer my question as to whether this occurred when the pump was replaced, we are going around in circles, at this poiint I would suggest you get some knowledgeable help to actually look at what is happening..

[kylcrappie]

opcorn: Let me start by Thanking Maxwedge, You’re a great asset to this site! My brake problem is fixed! ! ! ! To begin with my steering was getting hard to turn. Especially when your at a light turning or trying to back up So I replaced the power steering pump, after replacing the pump my breaks were sticking on both front wheels. So I started looking at what the power steering would affect by replacing the power steering pump. So from there I looked at the Hydro Boost system. The problem now is when you apply the breaks the front wheels would stick and the brake peddle will not come all the up. I would have to reach down and pull the peddle up to get it to release. So I replaced the Hydro Booster ($180.00) “Thinking this was the problem” NO! That didn’t fix it. Now I’m looking at the Master Cylinder, I replaced that Nope that’s not it. So I replaced the two front lines. Knowing the lines had to be bad not letting the fluid reverse back through the lines. “NOPE THAT DIDN’T FIX IT” (Now my wife is getting upset wanting to $$$ sale the truck). I've got good breaks but the peddle will not come all the way up. The peddle is stopping about 1 1/2 inches from the stop and the front breaks are sticking. So I replaced the two front calipers.........Guess what…… same problem..............Now there’s only one more thing that could be the problem. That’s The Proportioning Valve. So I found a valve and replaced it over the weekend. Guess what………Same problem. Now my wife is really “MAD” So I turned the lights off in the basement and come up stairs to clean up and take the family shopping. While in the shower IT HIT ME. The power steering lines I need to look at them. I went down stairs and looked at the Main line from the Power Steering to the Hydro Booster, The line was pinched off not letting the fluid go to the Booster. IT’S FIXED ! ! ! ! Now I feel like a real DUMB DUMB. But I have new breaks on the truck. Thanks for all your help here.


Charles from TN.

[MagicRat]

Thank you for the update, Charles!!