Weird brake issue...
#1
Weird brake issue...
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.
#2
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Car: 2000 Ford Focus
Engine: 2.0L CVH/SPI I-4
Transmission: IB5
Axle/Gears: stock
Re: Weird brake issue...
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.
#4
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Car: 1987 Chevrolet Camaro
Engine: 2.8L V6 MPFI
Transmission: 700R4
Axle/Gears: 10 Bolt
Re: Weird brake issue...
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.
#5
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Car: 91 Z28
Engine: 383 SuperRam
Transmission: ProBuilt 700r4
Axle/Gears: G92 3.23
Re: Weird brake issue...
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.
#6
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Car: 1992 Z28
Engine: L98 V8
Transmission: A4
Re: Weird brake issue...
I'd simply replace the brake master cylinder and see what happens. I had an old Ford with the same problem. Hope this helps.
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#8
Re: Weird brake issue...
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.
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.
Last edited by Oscar; 04-04-2008 at 06:16 PM.
#10
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Car: 2000 Ford Focus
Engine: 2.0L CVH/SPI I-4
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