No braking power (replaced vacuum booster)

[bryanwheat]

I have had this ongoing issue with one of my cars since i got it. I always assumed that it was the brake booster.

To make a long story short, i have to push the pedal down real hard to be able to stop, they don't lock up at all. IT feels as if the booster doesn't work properly, and that it isn't really assisting the braking system at all. Pedal is stiff, but the booster is working because when i start the car there is a little bit of difference in the pedal feel.

I have replaced the booster and vaccum hose with parts that came from a working car with a good working brake system. My motor pulls great vaccum, and still has good brake pads all the way around.

I am now leaning towards a stuck proportioning valve or some bad brake hoses, or somthing along those lines. What ever it is it is the same issue for all 4 brakes. Any input would be greatly appreciated. Thanks

 

[Defiant]

There's a vacuum check valve hiding in the big vacuum line running from the manifold to the booster. Make sure that it's in there, and make sure you don't have it on backward. You should only be able to blow from the booster to the manifold.

 

[bryanwheat]

I definetly put it on so that it can pull vaccum, thru it, but not blow pressure into the booster. I even changed it with a known good working one froma parts car that had really good brakes. I am gonna change some other things today, and see if that helps any.

 

[92awddsm]

Check the vacuum port on the intake manifold to make sure it is not clogged.

 

[bryanwheat]

Alright, i made sure that the nipple isn't clogged, and it for sure isn't, the vaccum to the booster is perfect. I even put another booster from a friends car in, and still crappy brakes. I have replaced booster, line with check valve, master cylinder, proportioning valve, front calipers, lines, and front pads and resurfaced rotors. Still can't lock the brakes up. For sure no air in the lines also. I am stumped on this one, i have basically replaced the complete brake system, and still crappy brakes. Lines are good and not clogged also. I am a little confused.

 

[Morphius]

To make a long story short, i have to push the pedal down real hard to be able to stop, they don't lock up at all. IT feels as if the booster doesn't work properly, and that it isn't really assisting the braking system at all. Pedal is stiff, but the booster is working because when i start the car there is a little bit of difference in the pedal feel.

I've had a booster fail and it acted as you described.

I have replaced the booster and vaccum hose with parts that came from a working car with a good working brake system.

You're 100% sure of this. Not another (parts) car that was good before? I can't speak as to what exactly fails, but it's given the age of these cars now, pretty much any used part could be suspect to being bad. Especially, if it's sat a lot. Seals/membranes dry out.

 

[bryanwheat]

I've put 2 in from parts cars, that worked previously, and one in from a friends car that works great in his car, and still worked great when i put it back in. I am gonna go buy some new brake hoses today, and see what happens.