Questions and Answers

Mushy Pedal And A Red Light Q. 1989 Chevy Pick up truck. Rear brake pipe rusted through, lost all fluid out of master cylinder for rear brakes and has rear wheel anti-lock brakes. I repaired the pipe, bled the master cylinder in all wheels. The brake pedal is still spongy and the brake light is on. I tried to bleed the master cylinder again and no change.

What else can I do to improve the brake and get the light out?

Randy

A. Most likely the combination valve is stuck because of pressure loss to rear wheels. I've sometimes got the valve to center itself by pumping the pedal real fast and very hard. The combination valve is under the master cylinder and isolation dump valve. Is should have a single wire to it that, if unplugged, will turn off red brake light. Also possibly lightly tapping on it in case it's frozen.

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