Brake problems, can anyone help me?!?
#16
Did you bleed the RABS unit? its on the drivers side frame below the cab, near the engine. That should probably be your first step.
Also, define "very poor brakes"
Is it poor as in hard pedal? Could be bad booster or vac pump.
Mushy pedal could be air in system, leak in system, bad fluid, bad brake hoses.
The RABS system in these trucks is pretty crappy in many peoples opinions. Its not really needed, and your truck should stop fine without it if everything else is working right.
Also, define "very poor brakes"
Is it poor as in hard pedal? Could be bad booster or vac pump.
Mushy pedal could be air in system, leak in system, bad fluid, bad brake hoses.
The RABS system in these trucks is pretty crappy in many peoples opinions. Its not really needed, and your truck should stop fine without it if everything else is working right.
#17
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if you pump the pedal 2-3 times, is the pedal hard to push after pumping?
if so, then you have a bad vacuum pump. if it is always hard to push, then you either have no vacuum or a bad booster.
to test the booster and pump, with the truck running, put a vacuum gauge in the vacuum circuit somewhere and see how much vacuum you have. for the brakes to work properly, you want at least 17 inches vacuum. then have someone step on the brake pedal 2-3 times, and see how far the vacuum drops and how long it takes to recover. it should not drop much, and should recover almost immediately. if not the pump is bad.
if the pump tests good, remove the line going into the booster and see if there is any difference in the way the pedal fells. with the line off the pedal should be very hard to push down.
if so, then you have a bad vacuum pump. if it is always hard to push, then you either have no vacuum or a bad booster.
to test the booster and pump, with the truck running, put a vacuum gauge in the vacuum circuit somewhere and see how much vacuum you have. for the brakes to work properly, you want at least 17 inches vacuum. then have someone step on the brake pedal 2-3 times, and see how far the vacuum drops and how long it takes to recover. it should not drop much, and should recover almost immediately. if not the pump is bad.
if the pump tests good, remove the line going into the booster and see if there is any difference in the way the pedal fells. with the line off the pedal should be very hard to push down.
#21
#23
Same here
My truck seems to have the same problem but when I look for a part on Autozone.com this is the only part Im finding (ABS Hydraulic Unit)
Cardone Reman/ABS Hydraulic Unit (12-2026) | 1994 Ford F250 3/4 ton P/U 4WD 8 Cylinders K 7.3L Turbo Diesel | AutoZone.com
is this the part you guys are talking about.
Mine brakes fine at first then its like the power assist just goes away
Cardone Reman/ABS Hydraulic Unit (12-2026) | 1994 Ford F250 3/4 ton P/U 4WD 8 Cylinders K 7.3L Turbo Diesel | AutoZone.com
is this the part you guys are talking about.
Mine brakes fine at first then its like the power assist just goes away
#24
Thats the rabs valve and heres the vac pumpList: Vacuum Pump - 1984 Ford F-250 | O'Reilly Auto Parts
#25
Thats the rabs valve and heres the vac pumpList: Vacuum Pump - 1984 Ford F-250 | O'Reilly Auto Parts
#26
#29
Does the brake proportioing valve have any part in bleeding the brakes?
I have a similar issue, but I don't have that fancy RABS thing.
All new lines, calipers/pads, hoses, a known good used master cylinder and booster (Working great on previous truck), wheel cylinders and shoes.
The only thing I haven't replaced is the vacuum pump, but I have 2 used spares to try.
I have the same feeling in the pedal. I push it, and it's firm...but seems to take a looong time to stop.
I have a similar issue, but I don't have that fancy RABS thing.
All new lines, calipers/pads, hoses, a known good used master cylinder and booster (Working great on previous truck), wheel cylinders and shoes.
The only thing I haven't replaced is the vacuum pump, but I have 2 used spares to try.
I have the same feeling in the pedal. I push it, and it's firm...but seems to take a looong time to stop.