Hydroboost problem

[svobronco]

Finally finished my hydro install. I rebuilt a unit from a SuperDuty and it seemed to go right, but now I'm not so sure.
The pedal is very hard to push, but the brakes do work quite well when you stand on it. But, the brakes release very slowly. I can take my foot off the pedal and braking continues.
I loosened up the MC nuts to make sure the pushrod isn't preloading the MC and it made no difference.
Should I just suck it up and buy a reman?

 

[hankjr]

hey Greg. are you sure the little shuttle valve went back in correctly? it sounds like pressure is blowing past "at rest" creating strong peddle feel and not exiting properly creating lag.

you sure you got the air out as well? mine was strange until i got the air out

Hank

 

[Apogee]

How do you have the return line plumbed from the booster to the pump/reservoir? You don't want any pressure on the return side of the booster, so an incorrectly oriented tee fitting or something can cause issues as well.

 

[svobronco]

hey Greg. are you sure the little shuttle valve went back in correctly? it sounds like pressure is blowing past "at rest" creating strong peddle feel and not exiting properly creating lag.

you sure you got the air out as well? mine was strange until i got the air out

Hank

IIRC, what came out of the bag of new parts didn't match what I took out, so I either put the old parts back in or used the new stuff as best as I could figure. Not sure, but that may very well be the problem. I re-bled the system today and got a good burp after working it for a few minutes. Pedal got easier, but it still hangs up.
Brakes release easily if I pull up on the pedal, it doesn't take much travel to do it.
It's not pushrod length as I put 1/4" washers between the MC and HB and it just moved the problem down the line.
No binding in the linkage, I undid that and it just stayed there.
It does retract as soon as I shut of the engine. And when pedal is pushed with the eng off, it retracts right away.

How do you have the return line plumbed from the booster to the pump/reservoir? You don't want any pressure on the return side of the booster, so an incorrectly oriented tee fitting or something can cause issues as well.

I have a dedicated line to a previously unused nipple on the reservoir, it does have a 90* fitting, but it flows just as much as the original straight fitting does.


Thinking I need to pull it apart and check my work....I have nothing better to do for the next 2 weeks....