so here it goes. when i cold start my 92rs and pull away, i am able to put the brake pedal to the ground and it will roll for about 5ft before stopping. however, it seems that when the brakes warm up after about 10 mins or so of driving, they work fine and stop as they should. I have the stock brakes up front w/ HPS pads and summit rotors and PBR disc brakes in the rear w/ HPS pads. Car has been doing this for quite some time now. Any help is appreciated.

 

My only guess is you brake master cylinder may be heading for the hills. Check your fluid level, lines, pads etc etc. I had a buddy with a Dodge truck that did the same thing, and a master cylinder fixed it. Don't quote me it, but that's my educated guess.

 

thanks for the input

 

my 88' does the samething, thought it was normal, my idle is around 600 cold and 800 when in closed loop, the reason they suck *** is because the vacuum power isn't as great im pretty sure of, because when closed loop hits they become stronger.

 

another thing to think about is.... some brake pads work better at higher tempertures. i use Performance Friction carbon metallics because they work the best at higher tempertures, and thirdgen brakes are not the best, and can get quite hot.

 

I'd simply replace the brake master cylinder and see what happens. I had an old Ford with the same problem. Hope this helps.

 

thanks for the help. ill give the master cyl. a try.

 

Here's what I believe is happening. First I'll say that I do believe it is a master cyclinder problem.

So what I believe is happening is that when you first start the car, the brake fluid and seals are all cold. The car continues to roll because the fluid is bypassing the rubber cups inside the MC. Maybe your pedal also goes lower then usual, not sure since you didn't mention. If the fluid is flowing around the cups then you would not have good braking. Once the brake fluid warms up, so do the rubbers. And you know that when things warm up, they also expand. The rubber cups now being warm and expanded now provide enough seal so that the brake fluid doesn't flow around the cups and now it puts all the pressure in through the brake lines and eventually to the brakes. So after it is warmed up, it stops fin. Eventually those rubber cups though will be so worn out that even after they heat up, they will not have expanded enough to provide that same seal.

 

No problem irish. I have a friend named Ian who just messed up my brakes. I just want to
KILL IAN!!!

 

Let me know how the master cylinder goes.

 

old thread, but just got around to fixing my problem. I determined that the problem was the brake booster. Replaced it today and brakes are 100x better. Thanks for the help though.