Everytime I start my car up my brake pedal travels properly and responds normally. As soon as I drive and use the brakes, the pedal travels less and becomes harder to press.

I have tested brake booster by pumping brakes while vehicle off, making the pedal hard then starting the engine and the pedal releases.

Thinking it is my brake booster but not sure, just want some feedback.

Changed all brakes, calipers, drums, and front brake lines and had it flushed.

Phil

 

sounds like a vacuum issue theres a little valve on the booster where the big vacum hose hooks to dont sound like its holding vacuum...

 

I checked the valve and it ok. Maybe the grommet or hose. I will look at that

 

It sounds like the one way check valve is bad. That valve should hold vacuum in the booster even when the engine is not running.

 

Ok I checked the valve again. I can blow through the side that goes into the booster. The side that the brake vacuum hose is on does not allow air through. Is this right?

 

thats backwards ,air should be able to be blown thru the booster nipple and not thru the hose nipple air/suction goes this direction

 

Ok let me look again and make sure. Thanks for the pic

 

check valve is fine. I am going to say there is a vacuum leak some where.

 

very possible the booster it self is not holding vacuum,

 

found thishttp://www.type2.com/library/brakes/vacboo.htm