Brake failure

[vn2nv]

Hi guys,
I get random brake failures sometimes and the car won't brake at all when I press down on the pedal. I know its my brake booster and master cylinder malfunctioning.
What I want to know is: When your brake booster diaphragm blows, will the fuel economy and engine power go shithouse? The car is driving like a slug with little or no brakes.

Thanks for any help.
vn2nv

[noah_73]

Could well do. You will reduce the amount of vacuum in the inlet manifold and this will mess with you MAP sensor, this in turn will have your ECU thinking your engine is under light load when it could well be the opposite.

[Hairy Eater]

check the vacum hose from the booster to engine... usually there's only spring steel wire clamps and they wear into the hose.... if they are loose just replace with screw type hose clamps... you might have to cut off the ends of the hose too( 1 inch) ... also after running your engine for a few minutes... turn it off... then pull out the non return valve that the vacum hose clamps onto at the booster.... you should hear the booster suck in air..... Also after the car has been sitting over night.... you should be able to do this again and hear a hissing sound as the booster vacum sucks in air..... if not, check the rubber gromet sealing the non return valve, check the non return valve too.... or the booster diaphram rubber may be perished and letting air getting sucked in... this would mean getting a reconditioned or new booster..

[lazyass]

When the booster goes your pedal should be hard as you don't get the vacuum assistance and when your master cyl goes your pedal normally goes to the floor or you may have to pump it a few times to build the pressure up.Is this similar to what you have?
In some early cars when the diaphragm goes the revs change up/down when the brakes are applied.