HI,

The above Van, just got a "brake job" done at the local Sears automotive dept. After I left, I got a antilock brake Rear light on the dash. I then took it back to them to have them look at it again, and they said that they did not touch the ABS, but would look at it. They bled the back brake lines and gave it back to me. I now have a
Brake ((I)(P)) light on. The brakes seem to be working good, but the light causes concern. I took it to the local Ford Dealer but they refused to look at it as it was a 91.

Any ideas, thoughts, help would be appreciated.

Doug

 

This commonly occurs following brake procedures. During the bleeding, air gets trapped in the pressure differential valve inside the master cylinder. On your 91', there should be a bleeder valve located on the front of the master cylinder as you view it from the engine compartment. To the side of the bleeder valve is a red connector with two wires. Remove the connector, start the engine and see if the light remains off. If so, you have air trapped.

Try attaching a short section of 1/8" diameter tubing to the bleeder valve and place the other end into the fluid in the master cylinder, securing the tubing to the lip of the MC with a clothespin or similar clamp. There is a float in the MC, be sure the tubing does not interfere with the float. With engine stopped, have an assistant pump up the brakes until firm. Release the bleeder gradually with a small wrench, allowing the pedal to travel approximately half way down. Do NOT allow the pedal to go all the way to the floor. Repeat this several times, start the engine and see if the light goes out.

If they ran the MC very low or dry, you may also have air trapped withing the rear anti-lock brake system (RABS) valve itself. This is very difficult to remove, but will often dissipate on its own over a period of time.

When the light is on, the RABS is disabled, but your rear brakes still function, just without the anti-lock capability. If the light does not go out in a few days, post back for further help. These RABS systems are touchy and extremely frustrating when searching for a cure.

 

Thank you very much. They did replace the MC so I expect your synopsis
is correct. I will probably have to bleed the RABS. as well, or take it back to sears and make them do it.

doug

 

Bingo! This model master cylinder cannot be bench bled like most others due to its design. I expect they did a bench bleed only. Chasing the air as directed should solve your problem.