Not your typical brake problem.
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Freshman User
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Not your typical brake problem.
Well just bought a 2000 Ford F 250 4x4 with 4 wheel abs and it has a brake problem. The abs light is on. So here's the description of my problem:
Driving down the road and you press on the brakes they work great. Coming to a stop sign / light and you start to feather the pedal to come to a smooth stop is when it goes to crap. First press on the pedal is good but when eased off slightly and reapply pressure it travels farther to the floor and each time you ease off slightly and reapply pressure it travels farther to the floor until eventually you run out of brakes. There are no leaks. I've bled the system multiple times and it has new fluid coming out of all the fittings. Thanks for any help on this one cause its a little peculiar to me.
Driving down the road and you press on the brakes they work great. Coming to a stop sign / light and you start to feather the pedal to come to a smooth stop is when it goes to crap. First press on the pedal is good but when eased off slightly and reapply pressure it travels farther to the floor and each time you ease off slightly and reapply pressure it travels farther to the floor until eventually you run out of brakes. There are no leaks. I've bled the system multiple times and it has new fluid coming out of all the fittings. Thanks for any help on this one cause its a little peculiar to me.
Hotshot
Joined: Aug 2006
Posts: 17,398
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From: Whittier, CA
Sounds like the master cylinder is going out on you. The fluid is passing the U-cups, back into the resevoir, so it doesn't leak externally, it just doesn't hold pressure.
Not sure about the ABS light. Is the fluid level full?
Not sure about the ABS light. Is the fluid level full?
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well when i got the truck the front drivers abs wire was ripped out of the clip. i tried to wire it back together and unplug the battery to clear the code but it didnt go away so i don't know. and if it was leaking pass the u cups why do they work great when you just mash on them and don't let up? as long as you dont ease off the pedal the brakes are great. i would think if it was leaking at all that if i mashed on them it would slowly go to the floor? yes? no? money is kind of tight right now so im just trying to figure out the problem before i go spending more.
Hotshot
Joined: Aug 2006
Posts: 17,398
Likes: 317
From: Whittier, CA
Okay, so you may have a sensor problem that's causing the ABS issue.
I think the fading brakes is a separate and unrelated issue. Your symptom is classic for a failing master cylinder. When you press the brake hard, the U-cup is forced open against the walls of the bore and it holds pressure. But when you press the brake lightly, the U-cup relaxes away from the walls of the bore and fluid leaks past.
If you pump the brakes hard, it will build pressure and hold again, right?
I think the fading brakes is a separate and unrelated issue. Your symptom is classic for a failing master cylinder. When you press the brake hard, the U-cup is forced open against the walls of the bore and it holds pressure. But when you press the brake lightly, the U-cup relaxes away from the walls of the bore and fluid leaks past.
If you pump the brakes hard, it will build pressure and hold again, right?
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actually never tried to pump them up right away. just once you start driving again and then press the pedal presusre is back. i also went and read how stuff works on master cylinders and it makes sense so it looks like i might be changing that out.
More Turbo
Joined: Aug 2006
Posts: 530
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From: W. Wisc
+2. It may also solve your ABS issue, but I wouldn't count on it. BTW if the ABS light is on, then you do NOT have ABS control - just normal brakes. Just so you are aware...
-Dave
-Dave
