'87 full size Braking Problem

[billandmissy]

Hello all,

I search the forums and found a few helpful hints but no answers, I'm at a loss and hope someone can help.

I've got an '87 full size Bronco, 302, automatic, RABS, stock drums rear and disks front. I replaced the MC (bench bled), replaced the rear shoes (and adjusted), replaced the hoses, bled the entire system (1st the RABS then rr,lr,rf,lf). Front pads are in excellent condition. I can pump them up fairly solid without the engine running, the pedal doesn't creep to the floor holding pressure. The RABS light is not on except for 1 sec at startup, same as the brake light. I can find no signs of leaks or bad/bulging hoses.

The brakes work and will stop the vehicle but if I push ******* the pedal it goes to the floor. The vehicle will not stop fast and none of the brakes will lock hard. If there were an emergency I would not be able to stop in time to avoid it.

That's about all the info I can think to add. If there is something I missed please post and I will answer it.

I'm out of ideas, any help would be appreciated and is needed.

 

[snowman74]

Sounds to me like you've still got air in it somewhere. I'd try bleeding it again.

 

[KansasBronco]

hey, i did the same to mine. i dont know exactly why it lights up, but if the brakes work, then i would put electrical tape on the light....

 

[billandmissy]

Ok, went out this morning and bypassed the RABS, bled the system and the brakes work fine.

Since this rig is for my wife, and I want it safe for her to drive this winter, I'll be finding and reinstalling a new (or rebuilt) RABS valve next week.

Thank you to those that responded, I appreciate your input.

 

[snowman74]

RABS is kinda a joke to me...I mean, it would make more sense if it were FABS instead as the majority of your braking is with your front breaks...duh. I've never understood why Ford used a rear system only.

So was it air in the system, or do you think the RABS unit went out? Even if the anti-lock feature goes out, it's my understanding that mechanical brakes take over, but I'm not certain. Luckily, mine has never gone out....knock on wood. Glad you got it working.

Snowman74 >-

 

[billandmissy]

As I understand it the RABS does serve a purpose or two.

It helps when pulling loads by replacing the older type of level sensor to keep your rear end from becoming your front end (might be a bitch with a trailer leading your way).

In slippery conditions it also keeps your ass behind you, always a good idea.

Personally, I'm with you, I don't like it. I would rather be in control of my braking than allowing a valve to do it for me.

It is definitely the RABS valve, with the valve stuck open it's bypassing the fluid into a holding tank of sorts. The fluid returns to your system/reservoir when you release the brakes. I power bled the brakes at all five points (RABS valve, RR, RL, FR, FL) and adjusted the rear brakes. After that didn't work I bypasses the RABS and the brakes started working.

Hope you never have the same problem. Later

 

[snowman74]

Eventually I want to do a rear disk conversion, and completely take the ABS system out of the loop. Has anybody done that successfully? Anyway, I'm glad you got er' done. Nothing sucks like no braking power. Thanks for the info on the RABS, I never thought about that trailering thing.

Snowman74 >-