rock hard brake pedal

[nutzak]

I was driving home, and the brake pedal got rock hard. The pump ran and made a whining noise (similar to a power steering pump whine), and the pedal is rock hard. The brake light is on, and if I push really hard I can stop the car. Any suggestions or ideas would be greatly appreciated.

[BJM]

Since you mentioned pump noise I assume you have a Power Master. Does the pump stop after a while? Note: Do not let the pump run for more than 30 seconds at a time under load or you risk overheating it. If it does stop but starts again after applying the brakes then your accumulator is most likely discharged and needs replacement. The rock hard part means you are braking manually without boost.

[nutzak]

When I apply the brakes, I don't hear the pump. I only have driven it home and in & out of my shop. So basiclly (sp?) I have no pump noise, an empty resovour on the inside (away from the fender), and a rock hard pedal. I appreciate the help.

[BJM]

With the key off pump the pedal hard 10 times. The right hand reservoir should be full at that point. If not, try adding fluid. The pressure switch (on top and behind the reservoir should be calling for the pump to turn on. If its bad then try powering the motor directly. As soon as more than one thing has been determined to be bad then buy the Autozone rebuilt. Search for BJM and PowerMaster and you will find the thread. Mine only needed the accumulator but it sounds like yours is not pumping. If you can pump by applying power to the motor (you could jumper the pressure switch connector) then its just the switch. If jumpering makes it pump, pump only for 13-15 seconds and try the brakes, they should feel fine then.