Horrible Brakes...

[dk05]

Here's the problem... Ever since I got my GTP it has had very very bad brakes, and as I have been driving other cars lately I have REALLY started to notice just how bad they really are. I just changed the pads on Friday and bled all four tires, that seemed ok, I had brakes at about 3/4 pedal. Then I drove the thing and noticed, wow.... nothing has improved at all, I have to push the pedal down 1/2 way to get any kind of response and then if I need to stop.... somewhat quick...... BAM right to the floor til they click, then I hit them again and it's up to like 3/4 pedal for a sec and right to the floor again... it seriously takes me 6 seconds to come to a complete stop from 25 MPH. Brake fluid is not low and all four bleeders shoot out straight fluid with no air bubbles. When I was doing the timing belt I did notice that the brake booster line was a little bit soft, but that couldn't affect the brakes that much, could it? Something is telling me that my master cylinder is bad..... no idea....

~Dk

[RollinonZ34]

I would go ahead and replace the Vacuum Booster Line that goes to the
back of the rear valve cover if it is getting spongy...It is Cheap and it might help. Gonna need to change it in the near future anyway as they suck. Changed mine when i pulled off the Plenum and noticed it...did not even know it was there until i went to replace Intake Gaskets and noticed it was Soft & Spongy, so i changed it. They colapse when they get soft & older and do affect braking. Brakes better now...Just a thought.

I would say to check for leaks in lines but you say that fluid level is ok!
You may be right in your guesswork of Master Cylinder. Wish i knew how to advise you on how to check, but im not a Mechanic, but changing my Boster Hose did help, as my car is 11 years old and could easily squeeze hose closed with fingers.

[birdman]

ive got the exact same problem and know what it is!! I would almost put money on your rear slide pins. the way to check them is to remove the rear calipars and where the two bolts go through there are metal sleevs that are supposed to move freely to center the caliper when the piston hits the rotor, but if they are frozen the pistion has to move further and only hits the rotor on one side. if you cant move those sleevs with your finger they are frozen. you can either try to hit them out with a hammer and put anti sieze in there but your best bet is to get new rear calipers. hope this helps.

[slick94prix]

Little experiment for ya. Before you apply your brakes to do the major stopping, pump the brakes once, let up, then apply them to stop. If it makes a difference, post.

[dk05]

Thanks for the replies. I will try the booster hose at some time. As far as the rear calipers go, the one on the driver side is all good but when I replaced the brake pads last weekend I did change the passenger side one, so now they are both good. When I pump the brakes, sometimes it helps, sometimes it makes them worse... it's really strange.


~Dk