Which Vacuum brake pedal?!?

[Ghettopoptart]

Ok, So here is where I am on this.

My powermaster took a crap on me (Surprise) and I pieced together the vacuum kit myself. I got the master/booster combo (all parts new) from a 1987 Monte Carlo SS , dual diaphram. Kirbans vacuum block, and the Brake pedal from a 1979 El Camino.

It feels squishy, and the pedal sits low, and won't return all the way up to the brake switches. I'm at a loss, what did I do wrong here?


Wrong pedal perhaps?

 

[malibudave1978]

Vacuum Boosted pedals are all the same.

What kind of master cylinder are you running? A strait bore or step bore master cylinder?

 

[Ghettopoptart]

I'm not sure the difference, but its whatever would come on a 87 Monte Carlo SS. Rock auto sent the combo.

 

[malibudave1978]

Easiest thing is to check is to adjust the rear brake shoes out against the drum brakes. This will cause a low pedal and no pressure in the line.

Do you have the correct pushrod in the booster that contacts the back of the master cylinder when the pedal is pressed? This will cause a low pedal.

If that doesn't help, it seems as if you have air in the master cylinder
OR
you have a bad master cylinder

It sounds as if you have a step bore master cylinder, which requires special attention when bench bleeding it to get all the air out of it. I would bench bleed it again pushing the piston of the master cylinder in very, very slowly until you do not see any additional air bubbles. If the bubbles never dissipate, I would think it to be a bad master cylinder.