I just searched on this for a while and coulnd't find any similar problems. My brakes have been working fine for months then all of a sudden when I go to brake they don't work well and the pedal is extremely stiff. It still brakes, but not well and it is really hard. Any help would be greatly appreciated.

 

Similar thing happened to me and it turned out that the hose from the manifold to the brake booster was clogged.

You get brakes but no power assist.

Mine is a race car and the brakes would work for about 1 lap and then they would get very stiff. The hose was not completely clogged but you need to have some vacuum to recharge the booster and full WOT racing will not supply enough vaccum to recharge the booster if the hose is partly clogged.

Come into the pits - hey! the brakes work fine - go out on the track - yikes! no brakes.

ed

 

It sounds like a booster problem. But usually they dont just fail like that all of a sudden.

 

Start simple. Check to make sure that your brake resevoir is full and if it is, try bleeding the brakes to make sure there is no air in the lines.

 

Well I checked the brake fluid.... fine. I put new slotted rotors and new axis pads on about 3 months ago and had the brakes bled at a shop. They have worked fine for this whole time then bam they stop very weird.

 

Have you checked the booster yet, like the replies above have recommended? Air in the lines would give the exact opposite of a hard pedal. If the booster is not getting vacuum, or if the diaphragm inside it is punctured, the sympton would be as you described - A very hard pedal, all of a sudden. The booster usually either works or it doesn't. There's really no middle ground.

 

This needs to be a sticky. Hydraulics for teh power brakes.

 

Well it turned out to be a crimped vacuum hose. I accidentally bent and crimped the hose taking off the stock manifold heat shield. Uncrimped the hose and she works fine once again.

 

HEY! What did you do to unclog? NoPistons, there is some middle ground. Every now and then I would get a good strong (sensitvie) pedal and man the things would bite! But most of the time it feels like a normal heavy pedal.


I just looked and there are two hoses, one on each side of the metal pipe that is the vacuum line for the booster. I would get into it, but the hoses are pretty stiff and no need to go replacin' if the clog could very well be in the pipe.


Do you just unclamp the hoses and fit a water or air hose and go full blast? And I can't help but think a clog could ruin or accelerate the life of the power brake unit.

 

My clog was at the manifold so I just punched it out with a wire.


Find the gunk in the hose.

Remove the gunk.

 

i had the same problem. mine was the brake booster it was crazy hard switched it out and i have brakes again.

 

It could've just been the check valve