Warning brake light

New to this forum. Just did a major brake overhaul to my 74 Bronco. Changes the shoes, cylinders, springs, and all the hoses. After we were finished bleeding the system, the brake warning lamp on the dash won't go out...Have tried to reset the valve were the light switch is located as described in the shop manual (turn on ignition, press brake pedal and light will go off), but the light keeps shining :mellow: Anybody have a tip for me?? Maybe I have to dismantle the valve....Have checked the switch with an ohm-meter, and it seems to be ok. janroger64.

I think that the plunger is probably stuck thinking that the piston is still in the lower pressure area, i think that it can be taken out and cleaned. do the brakes feel ok? is master cylinder full?

Did you have the P.V. pin pulled out when you bled the brakes? That's what I had to do to get the light to go off. I didn't use a clip as shown in the attached pic, I used a pair of neddle nose vice grips, and wedged it out with a flat head screwdriver

Bronc76 said:

I think that the plunger is probably stuck thinking that the piston is still in the lower pressure area, i think that it can be taken out and cleaned. do the brakes feel ok? is master cylinder full?

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Have to agree with you on that. I'll take it off and clean it. There's a ***** on the end that will let me get to the plunger (piston). We machined a dummy switch yesterday, so we can use that to lock the piston in it's middle position when we bleed the brakes again. Do you think it's necesarry to bleed the main sylinder by itself before we proceed to bleeding the wheel cylinders? Brakes feel a bit strange, but when the piston is blocking the low pressure side (rear) it makes sense...and I guess new linings take a while to "adjust" to the drums. Did not change the drums. They didn't show any wear at all.

76Explorer said:

Did you have the P.V. pin pulled out when you bled the brakes? That's what I had to do to get the light to go off. I didn't use a clip as shown in the attached pic, I used a pair of neddle nose vice grips, and wedged it out with a flat head screwdriver

Click to expand...

I don't have that type of valve on my 74. Think I'll have to take apart the valve and try to senter the piston before I bleed the system again. Think the piston might be stuck in the low pressure area in the valve. Thanks for your reply, though. /emoticons/[email protected] 2x" width="20" height="20" />

"Do you think it's necesarry to bleed the main cylinder by itself before we proceed......"

Always best to bench prime/bleed the M/C prior to installation.

OTHERWISE., it becomes a main source of air/bubbles during cylinder bleeding.

Fixed the problem /emoticons/[email protected] 2x" width="20" height="20" /> Took apart the valve yesterday, and the piston inside was stuck on the high pressure side (front). Had to take it out with needle nose pliers...Cleaned it up, put it together, and locked the piston in center position with the dummy switch we machined the other night. Bled the brakes and everything was in order. Light only flickers as it should when the key is in the run position, and the brakes feel normal. Thanks for all the replies concerning my brake problem.

janroger64 said:

Fixed the problem /emoticons/[email protected] 2x" width="20" height="20" /> Took apart the valve yesterday, and the piston inside was stuck on the high pressure side (front). Had to take it out with needle nose pliers...Cleaned it up, put it together, and locked the piston in center position with the dummy switch we machined the other night. Bled the brakes and everything was in order. Light only flickers as it should when the key is in the run position, and the brakes feel normal. Thanks for all the replies concerning my brake problem.

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there is a light for the brakes????? hahaha I thought lights where for seeing ,....glad you fixed your brakes that is more important then the engine pushing the bronco safty first