BRAKE LIGHT STAYS ON HELP !

[Nobody Cares]

The brake light had been staying on for a couple of weeks. 1980 vette. Brake pedal was getting a little spongy. I changed the master cylinder today and bleed all the lines. Brakes are working great now. But the brake light between the speedo and tach stays on. I pulled the tan and white wire off the brake porportioning valve and the brake light went out. I tested the wire with a tester at the pug (where it plugs into the porportioning valve ) and there is power there all the time. I plugged it back in the porportioning vavle and the brake light stays on. Can anyone give some ideas what to do or check. THnx Dave

 

[gmjunkie]

The brake light had been staying on for a couple of weeks. 1980 vette. Brake pedal was getting a little spongy. I changed the master cylinder today and bleed all the lines. Brakes are working great now. But the brake light between the speedo and tach stays on. I pulled the tan and white wire off the brake porportioning valve and the brake light went out. I tested the wire with a tester at the pug (where it plugs into the porportioning valve ) and there is power there all the time. I plugged it back in the porportioning vavle and the brake light stays on. Can anyone give some ideas what to do or check. THnx Dave

How did you bleed the brakes?? RR,LR,RF,LF?? Proportioning valve may be stuck!!

 

[Nobody Cares]

Front first then the rear. Any ideas if the porportioning valve is stuck. Get out the hammer ???? Dave

 

[gmjunkie]

Front first then the rear. Any ideas if the porportioning valve is stuck. Get out the hammer ???? Dave

Try starting at the right rear to left rear to right front to left front!!! 3 squirts RR,3 squirts LR, 3 squirts RF, 3 squirts LF and see if that don't help!! PS some proportioning valves has a rubber cap on each end and you can center them by hand!!

 

[22229stingray81]

Isn't there a way of resetting the brake "system" but pressing down HARD on the brake pedal for a few seconds? Perhaps try that and see if it goes out.


-Tatortot

 

[KANE]

The brake light had been staying on for a couple of weeks. 1980 vette. Brake pedal was getting a little spongy. I changed the master cylinder today and bleed all the lines. Brakes are working great now. But the brake light between the speedo and tach stays on. I pulled the tan and white wire off the brake porportioning valve and the brake light went out. I tested the wire with a tester at the pug (where it plugs into the porportioning valve ) and there is power there all the time. I plugged it back in the porportioning vavle and the brake light stays on. Can anyone give some ideas what to do or check. THnx Dave

Did you check for a bad connection at the e-brake switch? If I remember correctly, this little connection will trip the light on the dash too.

I have the same issue- I think it is a short in the parking brake switch because I know my proportioning valve is fine.

 

[GerryLP]

Isn't there a way of resetting the brake "system" but pressing down HARD on the brake pedal for a few seconds? Perhaps try that and see if it goes out.


-Tatortot

You are correct, Tatortot!

When there is a an uneven pressure on the proportioning valve, this will set the brake warning light, and to reset it, one has to correct the brake problem, bleed the system, and then press hard on the pedal to reset the balanced pressure and that will extinguish the light.

 

[22229stingray81]

You are correct, Tatortot!

I usually am, Gerry! otfl

 

[Nobody Cares]

No luck so far fellas. Pressed HARD on the brake pedal , but light is still on. Took the car out for a ride early this morning , light still on ??? :W

 

[Nobody Cares]

Anyone know if the should be power at the emergency brake switch ?? I pulled the wire off at the emergency brake switch , and had no power with the test light. ?? The only way so far that i been able to get the dash brake light to go out is pull the wire at the porportioning valve. Dave :confused

 

[wishuwerehere82]

No luck so far fellas. Pressed HARD on the brake pedal , but light is still on. Took the car out for a ride early this morning , light still on ??? :W

Usually just pressing hard on the pedal doesn't do it.
A couple of good hard stomps or stabs on the pedal will.
The idea is to get the fluid flowing fast and under pressure through the switch body to dislodge the piston from the cylinder.

 

[gmjunkie]

Anyone know if the should be power at the emergency brake switch ?? I pulled the wire off at the emergency brake switch , and had no power with the test light. ?? The only way so far that i been able to get the dash brake light to go out is pull the wire at the porportioning valve. Dave :confused

There won't be if the light is on,the light has already been grounded!!! If you unplug the proportioning valve,then there should be power!! the single wire to the valve and emergency brake are nothing more than a ground for the light that gets a Ground and turns on the light!!!Re-bleed the brakes starting at the wheel farthest from the Master Cylinder RR and then next farthest LR and then next farthest RF and then Last LF !~! C3's can be a real Bear to get ALL the air out,sometimes you will have to raise the rear of the car as far as possible and "PUMP The Hell OUT OF IT" and Hold solid pressure on the brake peddle!!!!

PS Be sure and bleed Outside of rear calipers First,Inside Second!!

 

[Nobody Cares]

Ok Thnx, I'll get er dun. Thnx for the info . Dave

 

[GerryLP]

On the L81, you have to press the pedal hard enough to develop 450 PSI line pressure, and when I did that, the force required to extinguish the light was higher than I thought...perhaps you have to stomp on the pedal as hard as it would be needed to bring the Vette to stop as if you were traveling 65 MPH.

That's how it seemed to me ....

 

[Nobody Cares]

Ok, I would have thought i had prssed hard enough but will give it another stomp or two. Thnx Dave :W:W:W:W

 

[6880 Mike]

...PS Be sure and bleed Outside of rear calipers First,Inside Second!!...

Other way around. Bleed inner rears first, outers second. Outers will never bleed if you're still pulling air through the inner halves.

 

[big2bird]

Other way around. Bleed inner rears first, outers second. Outers will never bleed if you're still pulling air through the inner halves.

Yep

 

[gmjunkie]

Other way around. Bleed inner rears first, outers second. Outers will never bleed if you're still pulling air through the inner halves.

Actually, I just went through every Genuine GM C3 Corvette Service Manual I have (69,76,79) and there is nothing on which half should be bled first, the only thing it says is Rear Wheels have to be removed to bleed the rear because there are 2 bleeders on the rear Calipers!!! It go's through Pressure Bleeding and Manual Bleeding Procedures, buts thats it!!I was taught in Technical School to always go the farthest from the Master Cylinder and work your way back!!! I've never had problems except on rare occasions when I've replaced all the steel lines and had to raise the rear of the car up high to get All the Air Out!!! Guess I've been Screwing Up for over 30 years!!

 

[big2bird]

Starting at the furthest from the master is correct. Bleeding the outer than inner bleeder on a single unit makes no sense to me.

 

[petes74ttop]

Brake light.

The light on the dash serves two functions, when you apply the e brake the light goes on, you indicated the that system is working properly.
You say the foot brakes work but the light wont go out.
It is not a proportioning valve but a balance valve, if the front or rear brakes use more fluid, due to a leak the " Valve " goes out of balance and the light comes on. Pump up pressure and open a front bleeder, if the light stays on pump up the pressure and bleed a rear brake, this will let the pistion in the balance valve move the other way a shut to light off.
Hope this helps. Pete.