Hydroboost problems?

[seadog]

After getting my hydroboost unit in my 78 chief it took a long time to get air out of system.Next after all the leaks I fixed I thought that was it.I took it on a 4 mile drive and the front brakes got really hot.Seems the higher the engine revs the more it puuls in the brake pedal.I put my foot underneath pedal and felt it pull in as engine revved.The steering is also hard to turn at idle but clears up with a tap on the gas.My brake pedal is very stiff.I got an AGR super pump w/78 caddy hydro unit on a caddy master cylinder.Do I need to do something special with my proportioning valve? :confused:

[seadog]

PLease help,this is the last problem I need to fix before moving on to paint/body work!!!!!!!

[JeepsAndGuns]

I'm not shure, do you think maby a hose is hooked up wrong?

[Retro93]

I see that you are using the Cadillac master cylinder. Did it come from a car originally equipped with rear disc brakes? I would suggest trying the Jeep m/c. Compare the Hydroboost push rod to the one in your old vacuum booster. The stickout length should be very similar between the two. Also...are you sure that the brake pedal actuator rod is not binding? Check the brake pedal linkage. To get the air out of the system, unhook the coil wire, turn the steering all the way to the left and then crank the engine. smile.gif

[seadog]

I am about to rip this thing out and trash it!All the air is out and I have the right master cylinder on there now,and the same problem.Could it be that my brand new h/b unit has a bad accumulator?What would happen if it did?It feels like when you first crank it,the pedal feels right and after a press or two it is hard as a rock and doesent want to let go completely.It has been a rodeo to try and keep my return line from leaking at the hose clamps too.

[Retro93]

Seadog,

You say that you are having a hard time keeping the return line from leaking? That should not be a problem since that is a very low pressure line. I just used 3/8" p/s hose and common clamps on my set up. Are you sure that you don't have the supply line from the pump crossed with the feed line to the p/s box? If my memory serves me correctly, the h/b feed line should be the one on the passenger side of the unit. I'll check tomorrow to make sure.

[FSJeeper]

I met Seadog this morning and I think we figured it out. He is running an aftermarket Hi Pressure power steering pump. Won't work with the hydroboost. Pretty sure a stock pump will solve his problem.

[River Beast]

Just so you know... not all HB units are 'good' if you get them off the shelf.... I have a re-man unit... that has an internal valving leak... when you start it up.. the pedal drops and drags the brakes.. like you describe... I ahve talked to many people on this.... if you idle and turn the wheel... watch the pedal... mine jumps and pump squeels a bit....

This is what I have it narrowed down to at my end with a stock pump...

FYI--- 76 Eldo HB... stock 78 Master cylinder.

it didnt do this when I first installed this unit last year... so this is where I'm at for my research.

[seadog]

I am going to buy a new pump and try that fist since they are cheap.I think like fsjeeper said is prolly gonna end up being the pump hopefully.Guess I got a brand new AGR SuperPump for sale.Thanks guys , hopefully my braking and cooling issues are done for!