Mechanics

F350 SOFT BRAKES

1995 Ford F-350

Brakes problem
1995 Ford F350 V8 Four Wheel Drive Manual 42000 miles

Brakes are hard with headlights on and are soft with headlights off. New brakes have been installed all around, including new spring kit in the rear, new parking brake cables, and new master cylinder. Everything has been bled several times. There is a 3-wire plug going into the master cylinder with the fourth wire taped off. I was told this is a pressure sensor switch. Could this be the root of my problem? It is the only electrical connection on the brake system. It does not have ABS. It is a '95 F350 Chassis Cab truck with a Mason's dump body installed on the chassis. It is 4-wheel drive, duel tires on rear.
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John Kline
February 9, 2010.




Does the truck have cruse control? Also, have the rear brakes been properly adjusted? Finally, check the front rubber brake hoses going to the caliper to make sure they are not expanding when the brakes are used.

Let me know.

Joe
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The truck does not have cruise control. The front brake lines are not swelling. The back brakes are adjusted properly. The problem seems to lie in the ABS pump underneath the driver's side located in the frame area. When unplugged, the brakes act normally. When plugged in, the back brakes get hard when the headlights are turned on and begin to heat up. Somewhere in the system of the ABS control pump and the headlight switch, there is a problem. Is there a quick fix? What else should I be looking for to find the link between the headlights and the brakes. As of right now I have left he ABS controller unplugged to operate the brakes normally.

Tiny
John Kline
Feb 15, 2010.
I'm a little confused. The first posting says it doesn't have ABS. That is why I asked about the cruse control. Based on your description, that is where the cruise cut off is located on the master cylender. As far as the rear brakes and the headlight switch, they are not connected unless you have a trailer tow package. Even then, the lights shouldn't cause the rear brakes to actuate and heat up unless they are electric brakes and they're not.

I will post this with the other techs to see if they have an answer.


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