Brake warning light.

Brakes, Suspension, Rims and Tires

  1. Joseph James

    Joseph James Senior Member

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    Any ideas? I have been unable to find anything leaking. Do the switches themselves ever fail?
     
  2. BLUPORT

    BLUPORT Carpe Diem Cras FCBO Gold Member

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    Is your emergency brake pedal engaged at all? The switch could have failed, and causing the false alarm.
     
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  3. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    Before doing anything, is the brake system properly bled? Is the light on all the time or only when the brakes are applied? Assuming the light is on all the time, the parking brake is either applied or the park brake switch has failed. If the light comes on as the brakes are applied, there is a pressure differential between the front and rear brakes. Usually this is caused by either a leak or a serious mis-adjustment issue. After eliminating the park brake as a potential source of the brake light, Put the car in park and apply the brakes, does the brake pedal sink as the brakes are held on? This can be an indicator of an internal leak in the master cylinder which could be causing the pressure differential. Pull the top off the master, are both chambers filled equally? If both chambers are not the same, you have a hidden leak someplace. Pull all four wheels and drums, check for a broken or disengaged brake adjuster or cable. A leaking wheel cylinder will have fluid residue inside of the end caps and if the leak is bad enough to trip the pressure switch, usually at least one wheel will have wet brake linings. If this car has disc brakes, check the seal around the caliper piston for brake fluid, if one is leaking, rebuild both calipers. Finally check all hoses and brake lines for wet spots, brake hoses crack and steel lines rust out. Check these things and report back.

    Dave
     
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  4. Joseph James

    Joseph James Senior Member

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    Parking brake is inoperative. No cable. I moved the pedal now that you mention it . I didn't pull the release because the cable isn't on the car. The light is on all the time.

    I found one rear wheel cylinder with a wet boot and replaced it. The other one was replaced a month ago.
     
  5. BLUPORT

    BLUPORT Carpe Diem Cras FCBO Gold Member

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    Check the switch.
     
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  6. Joseph James

    Joseph James Senior Member

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    I did change one of my out of round drums today. It took a long time. The adjuster was stuck. I had the spring loaded piece out of the way and it wouldn't move. Shoes were cracked. Old drum had chunks missing where I guess someone took a hammer to it. I ran out of daylight to do the other side.

    The old drum had a spring around it. Does it serve a purpose?
     
    Last edited: Apr 7, 2019
  7. Ross Wooldridge

    Ross Wooldridge Senior Member FCBO Gold Member

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    The spring is an anti-howl feature. Stops the drums from moaning.
     
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  8. CBODY67

    CBODY67 Senior Member

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    The parking brake switch is a simple ground situation. IF the wire going to it has chaffed or otherwise shorted to ground, the light would be on, possibly.
     
  9. Joseph James

    Joseph James Senior Member

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    It was the parking brake. D'oh! It was pushed down. I usually pay it no attention since it doesn't work.
     
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