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I have a 1995 F250 with a 7.5 ltr engine. I have had multiple problems with the RABS system. Ive changed out the ECU and speed sensor. I can drive for about 20 minutes then the red brake light and the ABS light comes on! I know that it is working as when I come to a stop you can feel the additional braking . And when moving again it tries to be still ingaged. The only other part in the system that I know about is the valve module. Also aftewr getting back to the house and putting on the code reader I dont get any codes.
Can anyone hepl with this problem!! Im very frustrated with it but Im suire Im not the oiny one whos had this problem! Thanks to anyone that can help!
You won’t get abs codes from the engine computer. It is a completely separate system.
The red brake light will disable the ABS system so it seems like you have a brake system problem and not necessarily an ABS problem. Has the recall been done? Is the float in the master cylinder stuck at the bottom?
I have a 1995 F250 with a 7.5 ltr engine. I have had multiple problems with the RABS system. Ive changed out the ECU and speed sensor. I can drive for about 20 minutes then the red brake light and the ABS light comes on! I know that it is working as when I come to a stop you can feel the additional braking . And when moving again it tries to be still ingaged. The only other part in the system that I know about is the valve module. Also aftewr getting back to the house and putting on the code reader I dont get any codes.
Can anyone hepl with this problem!! Im very frustrated with it but Im suire Im not the oiny one whos had this problem! Thanks to anyone that can help!
pull your pedal release and then with your hand pull the pedal to see if it’s not returning to released all the way. Also disconnect the rear cables momentarily if needed to.make sure not dragging
And when moving again it tries to be still ingaged.
I had this very problem too. Go underneath the truck and electrically disconnect the RABS valve (located on frame underneath driver's feet).
If the problem goes away the valve is needing some kind of attention.
With RABS valve disconnected, the brake system simply resorts to a regular pre RABS hydraulic brake system so no worries.
Ok. So now that you have disabled the ABS system that was already off, what does he do about the red brake light?
I think the OP is mis understanding how RABS operation would feel or perhaps has a out of round drum or damaged or warped or missing components or at the very least, air or hose or fluid issues.
The "system is working" sounds like grabbing or potentially just poor release and messed up frictions.
I think he should disconnect the RABS at the module simply to make sure its not at play for the activation of lights and see if it his pedal and his reservoir switch are ok, and then go from there. But he could just as easily check the codes like suggested first and see what it says.
But I think we have a mechanical issue, a F250 had a TSB for parking brake cables rubbing on a bracket near the (passenger?) side it may have been driver. My f150 had its cables out of the clips and it had partial applied basically, caused weird behavior
Ok. So now that you have disabled the ABS system that was already off,
You are quoting me quoting and responding to a specific behavior he mentioned. The RABS can fail and hold the rear brakes for a period of time and only slowly release them over time. On mine both "RABS" light and "Brake" dash lights came on when it was holding the rear brakes. Half hour later it was drive-able again. Unplugging RABS valve eliminated the problem.
If I remember correctly, (this is from more than 20 years ago) after disconnecting the RABS valve the dash warning lights went off
And you are assuming that the OPs RABS is "already off". The OP states:
Originally Posted by commo1955
I know that it is working as when I come to a stop you can feel the additional braking .
Originally Posted by My4Fordtrucks
what does he do about the red brake light?
You know the drill. You have to test first and not jump to conclusions. One step at a time.
And there could also be multiple problems setting off the brake light on dash.
The float in the MC is one. I would test and/or cycle the MC float switch a few times and make sure the fluid level is good.
Same for the switch on the parking brake .
Given the feeling of rear brakes continuing to hold pressure I would first be checking /testing the RABS valve (hydraulic unit) under the truck.
You can have the ABS light and not the red brake light but not the other way around. If the ABS light is on the system is supposed to be disabled. How do we know something else isn’t holding pressure on the rear brakes and the pulsation is actually the drums being out of round?
Here is the test procedure and a picture showing the location of the test wire and ABS computer module. I hope you kept your old engine computer.
Thanks and yes I have all the old parts! I have chercked the rear brakes and they seam ok . No cup leaking and the drums seam good. I will go thru again soon as Im in Denver Colorado and its not suppose to get over 32 for the next 4 days! Thanks agin to all!!! Mike
RABS problems
