My 95 GSR has mushy brakes, i have bled them several several times trying to eliminate air trapped in the system. I do not have a fluid leak but i would like to try replacing my master cylinder to see if that is my problem. I see where you can purchase the master cylinder or the cylinder with the brake booster? How can i tell if i need a new booster or not? Can that go bad? I just don't want to buy the master cylinder, change it and have the same problem while wondering if the booster was the problem.

Also my ABS light is on, but was on before i had the mushy braking problem, its throwing code 2 ( abs pump motor) i replaced the entire ABS assembly and i still have the same code...

 

Have you tried doing this:

With the car off, pump the brake pedal until it is very hard and hold it. the pedal shoud not sink. if it sinks a little or a lot, chances are you have a fluid leak/ failed hydraulic component (can be a caliper (internal) or hose). Keep in mind that a master cylinder can fail internally. Look at the area under the master cylinder. if you see any paint missing on the booster or a trace of brake fluid around it (and you havent dropped any from any fill ups) then your matser cylinder is leaking internally. also try this:

Same deal. Hold the pedal down after pumping it with the car off and turn the car on. the pedal should sink slightly. this is checking your booster for function/airtightness. I can already tell since you didnt throw out the fact that your pedal is always super hard (failed booster) the booster is fine as is the check valve mounted between the booster and manifold (on the firewall above the booster)

one more thing. if you by chance messed with the booster pushrod clearance and backed the rod out, your pedal would be mushy as hell and it would take alot of travel before your brakes actually grab. but if you havent replaced either of them you dont have to worry about this.
Good Luck


Modified by jr_deleon at 12:35 AM 10/12/2008

 

The thing that gets me, when i bought this car 3 years ago i had hard brakes, abs light was already on. i changed my front brake pads, bled them and ever since the day i changed them, they have gotten mushy, its worse in the summer time or on a hot day. its like i can't just brake once i have to brake hold, let off brake again, and then usually a third time just to get the car to stop.

One time i had a caliper eject on me, but it froze after that and i replaced that caliper. I have never ever had any sign of a low resevoir which would indicated a fluid leak, so i have always thought it to be a component rather than a leak. Fluid always has maintained correct level. I will try checking the booster again today, no its not hard while driving, but i will do that test as well. But what also bothers me is that all the fluid lines run to the abs unit, which i don't think has a leak but the abs light is on and i was thinking possibly would that effect it.

Then again i think maybe not seeing as how the abs was messed up when the brakes did work fine. I checked my abs light and it reads code 2, which my sheet says " abs pump motor" i replaced the entire abs unit and i have the same code, except the old one blew the 10a fuse in its little fuse box and this one does not.