So I've been having this problem that last couple summers on and off with my brakes. Most of the time the brakes are fine, but sometimes the brake pedal gets stiffer and it considerably affects my braking. I can slam on my breaks and not have the momentum throw me forwards at all, even my parents old oldmobile could do that.

Most of the time I can still brake in time (I downshift for engine brake if I really have to) but if someone slams on their brakes infront of me and I'm going decently fast I'm probably going to end up slamming into them, so I would like to try and get this problem fixed finally. Its an 88 GTA with 4 wheel disc. Any ideas?

 

Sounds like a brake booster issue. Is the vacuum line going to it in good shape?

Here's a test for the booster:
With the car shut off, pump the brakes several times to remove any stored vacuum in the booster. Then hold your foot on the brake pedal and start the car. The pedal should drop.

Good luck

 

I have this same problem in my RS, but it only does it every now, usually when the weather changes. ill have to do what di11avou said tomorow, and see if its my booster.

 

I had this same problem 4 wheel disc and now it does it all the time and I can hear hissing pressure loss inside the cab. no brake assitance at all i tried changing out just the check valve, gromment and hose no help so i'm putting on a new booster I guess..

 

I have an extra... Seemed to work fine when we junked the car...