why is my brake light on?

[Archangel]

The red "brake" idiot light is always on in my Townie, and I have no clue as to why. I tried unplugging the wire for the e-brake hoping that switch might have shorted out or something, but it didn't hel. I admit I did several burnouts at the Woodward cruise, but I don't think I have a blown caliper/wheel cylinder as the car stops just fine and I'm not losing any brake fluid. While at the cruise the light would come on while lightly riding the brakes and a hard press on pedal would make it go away, but then while going down the on-ramp for the freeway it came on by itself and now it just don't care about how light or hard I press on the pedal, as long as the car is running the damn thing is glowing. Any ideas please?

[91 LTD]

Have you tried pulling the ebrake pedal back? I dont usually use my parking brake but the times I have, after disengaging it the light stays on till I pull it back and it hits the switch that turns the light on and off. I think the spring gets weak .

[Paul_]

It's possible you blew one of the wheel cylinders in back.

[Archangel]

91 LTD, it's not the E-brake - I don't have the vacuum servo for it anymore so every time it's released ot goes all the way up with a loud bang. Switch is okay too, I disconnected the wire for it to make sure it doesn't close the circuit and turn the light on, but the light was still glowing.

Paul, I highly doubt I blew a cylinder, I'd be leaking fluid left and right every time I hit the brakes, and that is not the case - reservoir is full to the top, cars stops as good as ever. Light has been giving me trouble for the whole afternoon and evening, and I did lots of braking, if I had a leak in the system I'd be out of fluid by now, right?

[Paul_]

I only suggested it because I had a leaking wheel cylinder on my '86 and I never knew about it until I went to get it inspected. My mechanic got a bath when he pulled the drum.

If the car stops, and is not leaking, I tend to think it's a wiring issue.

[Archangel]

Paul, I honestly think the pressure switch is going bad - just pulled the drums, everything is rusty as hell in there, but moves smoothly and there are no leaks. I'll disconnect the harness for the switch and start saving up for disc brakes. One weird thing I noticed though, the brake pads in the rear are different length - the ones towards the front of the vehicle have like 3" shorter friction material rivetted to them than the ones towards the rear of the car. The brake shoes are the same length, only the friction material rivetted to them is different length. I have a set of brake pads new in the box, they are the same deal - what's up with that, it's practically a decrease of stopping power right there

[Archangel]

OK, went shopping tonight, brake light was glowing all the way to the store. When I came back out and heade home there was no light whatsoever, not even a blink. And no, it hasn't burnt out, the e-brake lights it just fine. Go figure

[AOD]

If the brakes are fine and you're not losing fluid, it sounds like the switch is bad.

I had a bad master cylinder and the light would go on when the pedal went to the floor.

[Archangel]

Well now that's weird, cause then the light came on during the Cruise that's how I'd put it off - press on the pedal as ghard as I can without actually flooring it.

[85crownHPP]

brake shoes are supposed to be one larger than the other.

[mrltd]

Check the connection on the switch by any chance?

[gadget73]

The wire down to the e-brake switch didn't get pinched in the brake mechanism did it? Could be the switch on top of the prop valve, or the wiring to it. I had a bad switch on my Beetle and it did the same thing, but only in the rain.

[Archangel]

MrLTD, pressure switch harness got unplugged, cleaned, greased with di-electric grease, then plugged back in, didn't make one bit of difference - slight still goes on and off at random times, but now at least it's happenning when I'm actually using the brakes. Cars still stops as good as ever, still no leaks anywhere.

Thain, the wire for the e-brake is fine, that was the first thing I checked. It's most likely the damn pressure switch on the proportional valve, but I ain't replacing it just yet..

[mrltd]

Guess it's the switch then...I'm sure Lincolnmania or someone has one sitting aorund...