power brakes not working

[73chevytruck]

Ok on my 73 chevy I barely have any brakes. I just replaced the brake booster and master cylinder and that didn't help at all. My front calipers are both moving just fine. But still no power brakes. Could the proportion valve be bad or stuck causeing this? Could I bypass it to get better brakes if that's the problem?
With the power of the new motor I need to beable to stop faster then it does now.

[85cHeavyMetalBogger]

hole in vacuum line?

[73chevytruck]

No it don't have any leaks. And does have brakes just not good ones. Also has a new line from back of carb to the brake booster to.

[xjs3667]

when you say no power breaks, you mean your pedal is really hard to push down? or is it going down and just not stopping you?

[73chevytruck]

The pedals hard to push down. There are brakes there just not what should be.

[xjs3667]

make sure you have the vacuum hooked up to good source, make sure the hose is not plugged, also did you pull the plug out that was on the vacuum port on the booster before you hooked up vac line?  this is what I forgot to do last time    and also hook up a vac gauge to make sure your getting good vacuum to booster. if all checks out, I would point to a bad booster, even though its new, I can't count how many times Ive gotten bad new parts

[4x4xdodgeman]

how big is the cam  you have in the motor?  may be you are not making any vacum to work the booster.

[4x4xdodgeman]

did the brakes work before the new motor?  should asked this frist

[73chevytruck]

no, the brakes didnt work any better the last time the truck was ran, it is getting vaccum at the booster unhook the line and you can hear and feel it, and its hooked to the back of the carb, and it was off another truck out of the junk yard, but it doing the same thing as the old one did.

[old school truck dude]

Stuck proportioning valve most likely.. Just take it apart and clean it up, probably rusty, sometimes you can just beat on it and make it work.. Dont bypass it. Make sure rears are adjusted up also.. Somethin is stoppin the flow of brake fluid, bleed brakes and make sure its makin it all the way to the back

[xjs3667]

yea it sounding like the proportioning valve, could be a little piece of rust trying to get thru the banjo bolt too, try pooping the calipers off and pressing the piston back in one side at atime, it might free up the blockage without making a mess with brake fluid again

[old school truck dude]

POOPING?

[Eroq]

trash the vacuum go hydroboost.. you'll never go back!