Brake fade/soft pedal--rabs bypass repair 92 F-250
#1
Join Date: Aug 2003
Location: west central wisconsin
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Brake fade/soft pedal--rabs bypass repair 92 F-250
After 2 hours of reading posts and waiting for all the ads to download from this website. I thought I might try to simplify this for the next guy.
My 92 F-250 had a soft brake pedal and would fade very quickly, pedal would quickly go to the floor. Of course the first thing I thought of is the master cylinder. Well three different MC made no difference. Also adjusted the rear brakes and bled the brake so many times I can't count. No change.
So here's the FIRST thing everyone needs to do. Yes, try this BEFORE you change out the MC. Under the drivers side floor board, inside the frame rail is the rear abs contoller/module. Facing the front is a large hex nut. Carefully remove this nut. I used a 1 1/4 inch box end wrench. This may not be the exact size but it is what worked for me. Simply remove the nut and TAKE OUT THE SPRING, caution the nut is under pressure from the sping. No brake fluid will leak out. Then replace the nut. Pump your brakes a few times to compress the controller. That's it. This bypasses the rabs contoller which has failed and is letting brake fluid leak by the seals which causes the brake pedal to fade. No the abs light will not light up on the dash.
Disclaimer:CAUTION This will disable the rear abs. Is the truck safe to drive now that you have good brakes but have disabled the rear abs? This is up to each owner to decide. The controller could be replaced, part cost $150-$250 so I was told.
I personally couldn't be happier to have my truck back on the road with good brakes FINALLY. Never really noticed the abs anyway, and certainly don't notice any difference without the abs. Except I have BRAKES.
Also this repair was posted by another forum member. Which I would really like to thank. So THANK YOU for posting this info. I'm just trying to make it easier to find. Maybe the next guy will not have to waste all the time and money like I did to find this simple repair.
My 92 F-250 had a soft brake pedal and would fade very quickly, pedal would quickly go to the floor. Of course the first thing I thought of is the master cylinder. Well three different MC made no difference. Also adjusted the rear brakes and bled the brake so many times I can't count. No change.
So here's the FIRST thing everyone needs to do. Yes, try this BEFORE you change out the MC. Under the drivers side floor board, inside the frame rail is the rear abs contoller/module. Facing the front is a large hex nut. Carefully remove this nut. I used a 1 1/4 inch box end wrench. This may not be the exact size but it is what worked for me. Simply remove the nut and TAKE OUT THE SPRING, caution the nut is under pressure from the sping. No brake fluid will leak out. Then replace the nut. Pump your brakes a few times to compress the controller. That's it. This bypasses the rabs contoller which has failed and is letting brake fluid leak by the seals which causes the brake pedal to fade. No the abs light will not light up on the dash.
Disclaimer:CAUTION This will disable the rear abs. Is the truck safe to drive now that you have good brakes but have disabled the rear abs? This is up to each owner to decide. The controller could be replaced, part cost $150-$250 so I was told.
I personally couldn't be happier to have my truck back on the road with good brakes FINALLY. Never really noticed the abs anyway, and certainly don't notice any difference without the abs. Except I have BRAKES.
Also this repair was posted by another forum member. Which I would really like to thank. So THANK YOU for posting this info. I'm just trying to make it easier to find. Maybe the next guy will not have to waste all the time and money like I did to find this simple repair.
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#2
Join Date: Nov 2003
Location: Campbell River, B.C.
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Glad my truck never had ABS. My Dad's GMC will randomly lock up one of the wheels, sometimes the front, sometimes the rear. Nearly sent him into the ditch one time when the front locked up, and nearly hit a deer the other time because it cut the breaking effect so much (WTF!!!). Works fine in a none emergency situation though....stupid ABS. Thanks for posting, I'm sure some one else will find this info useful. Break fade is something I heard more than a few times happening on RABS equipped ford trucks of the late 80s and early 90s.
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#10
Join Date: Mar 2005
Location: Marlboro Mental Hospital.
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i went one step farther and completely bypassed the ABS unit back in 1988 3 months or so after i bought the truck because i got tired of brakes that worked when they wanted to.
since i never had a vehicle with ABS, not having it on this truck was not a problem.
most of the vehicles i drive do not have abs, including my tractor trailers and dump trucks.
since i never had a vehicle with ABS, not having it on this truck was not a problem.
most of the vehicles i drive do not have abs, including my tractor trailers and dump trucks.
#11
Ya im with ya, i know how to drive and am not a big fan of ABS. Can the ABS "stick" so that the brakes drag? I have all the other described symptoms IE: feels like only the fronts working, randomly locking rear tires, pedal fade when i really push on it... and when i really push on it, thats when the brakes hang up. EVERYTHING is new minus the abs valve.
#12
Join Date: Mar 2005
Location: Marlboro Mental Hospital.
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i really can't say.
the only thing that has working abs is the crown vic. and the only reason that is not bypassed is i like the traction control feature in the winter.
it will sense wheel spin and apply a little brake so the limited slip diff will send more power to the other wheel, enabling the car to go just about anywhere in snow or slick conditions.
the only thing that has working abs is the crown vic. and the only reason that is not bypassed is i like the traction control feature in the winter.
it will sense wheel spin and apply a little brake so the limited slip diff will send more power to the other wheel, enabling the car to go just about anywhere in snow or slick conditions.
#13
Tried your fix. Worked like a charm. Out of curiosity, I wonder if this is only making the rear brakes work better since it is disabling the rear anti-lock brakes module. Either way, it stops much better than before. It would be nice to know the front brakes are still doing most of the work though.
#14
Join Date: Mar 2005
Location: Marlboro Mental Hospital.
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Tried your fix. Worked like a charm. Out of curiosity, I wonder if this is only making the rear brakes work better since it is disabling the rear anti-lock brakes module. Either way, it stops much better than before. It would be nice to know the front brakes are still doing most of the work though.
yes you are correct that this only effects the rear brakes.
there is no connection between the rear abs and the front brake circuit except that they both are connected to the master cylinder.
#15
Glad my truck never had ABS. My Dad's GMC will randomly lock up one of the wheels, sometimes the front, sometimes the rear. Nearly sent him into the ditch one time when the front locked up, and nearly hit a deer the other time because it cut the breaking effect so much (WTF!!!). Works fine in a none emergency situation though....stupid ABS. Thanks for posting, I'm sure some one else will find this info useful. Break fade is something I heard more than a few times happening on RABS equipped ford trucks of the late 80s and early 90s.