So I converted to hydro boost

[sam 74]

Now I have a question, being this is the first time ive used a hydro boost setup. I got the unit fabbed in and plumbed, and adapted to the break pedal, I bled the PS system and started the car and rebled PS system again, now I tested the brakes and they seem to work but I noticed when I hit the pedal it goes down then theres a kinda hiss and the pedal raises a little bit, is this normal? Also I noticed that the brakes take a second to let go after I'm off the pedal, do i need to add a return spring on the pedal?

[sam 74]

Think I figured it out, low pressure side has to much restriction so the T fitting is being removed and I added a direct return to the res itself, ths seems to be the issue with a lot of systems, that's what my searching turned up anyway.

[sam 74]

Got it sorted out, everything works great, it's nice to have assisted brakes again.

[Wall]

I do remember reading about the T-fittings causing restriction in hydro boost applications. They said you should always go back to the reservoir with all your returns and not T them together. That's cool you got it figured out.

[zamora7]

Curious as to what car you did it to and what parts you used, fabbed, etc.

[sam 74]

The car is a 74 olds, I had to fab up an adapter plate to go from stock booster bracket to the hydroboost unit, then I had cut the rod end off my vac booster drilled and tapped it for the threaded push rod that the hydroboost came with, then the plumbing is -6 ptfe hoses and fittings. I reused my master cylinder but I'm going to swap out to 1 1/8 master soon, I don't like making to many mods at once in case I need to trace down a problem.