I have been enjoying my super six conversion on my 76 volare so much that I decided to do some brake work to help deal with the extra power.

The brake light on the dash of the car has been on for a few months now.
The brakes were squeaking a bit and so I decided to do a full brake job on the front of the car.

I replaced: master cyl., front hoses, front rotors, front pads, front wheel bearings. I bled the master cyl once on the car and bled the brakes in the proper order. The brakes seem to be working fine, I have had to do a few extra rounds of bleeding to get the pedal nice and firm but things seem to be working well. Pedal still gets a tad mushy once in awhile but the brakes seem to work fine. This is a non power brake car.

I am a bit baffled though because even after all of this, I cant get the brake light on the dash to go off. I noticed that the light is hooked up to the porportioning valve. I am assuming that it is signaling something is not right inside this valve. Maybe even some air trapped in it?

I am sure I am not the only one to face this issue and I am sure there is a fix for it.

Any advice is greatly appreciated.

Dr Wheelie.

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Dr Wheelie

if its like any other mopar i've been in, that light is for the Emergency brake and usually lights up when its on, even one click or "wiggle" of the pedal can turn the light on

Justin

Assuming no funky shorts or anything...
The brake light in the dash can stay on if the switch behind the e-brake handle is stuck. Get under the dash and look at the e-brake handle. In back of it is a rod, follow this rod back and you'll see a switch similar to the one that activates the dome light. Pull the wire out of the switch or activate the switch by hand to see if the light goes off. If you find it is deffective I believe you can get these at the local parts houses, maybe in the HELP! section.

drwheelie, I'm not sure if a Volare uses a latching or a non-latching type brake pressure differential warning switch, but if it has the latter, you may have to go out and apply the brakes hard a couple of times to get the piston to re-center and put out the light.

If neither that or playing with the parking brake switch helps, you probably still have air in a line somewhere.

"DW"

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If it ain't broke, fix it!

Thanks for the advice. Ill check out these things and see what happens

I havent checked the back brakes at all but they bled fine. I dont think I have any leaks or anything. Could worn rear shoes also cause the light to go on? Like I said, the rears arent making any noise and seem to be working fine.

Could the problem also be the porportioning valve?

Thanks

DW

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Dr Wheelie

You could have a bad switch, but the shoes shouldn't cause it. Only a hydraulic problem should activate the light (or the parking brake).

"DW"

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If it ain't broke, fix it!

Check the connection at the proportioning valve. If it's loose, it could cause the light to come on.

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Everyone driving slower than me is a moron. Everyone driving faster than me is an idiot. With all these morons and idiots on the road, I can't get anywhere!

Since you say you get a mushy pedal at times, and that the light is still on, I would suspect that you still have air or a leak in the brake lines. Does the fluid go down any? Are the brake pads/shoes excessively worn? Any tell tale wet spots on the inside bottom of the wheels? If you hold the brake pedal down hard, does it slowly move, after a period of time?

Doc: This is probably your situation/problem
1.- Brake Warning Switch Operation
The hydraulic system brake warning switch warns the vehicle operator that one of the hydraulic systems has failed. A failure in one part of the brake system does not result in failure of the entire hydraulic brake system. As an example, failure of the rear brake system will leave the front brake system still operative.

If a pressure loss occurs in one side of the dual brake system, the difference in pressure causes the piston to move to the failed side and latch in the position. This will cause the brake system warning light to come on and stay on after the pedal is released. After the system is repaired and bled (see “Bleeding Brake System” in service adjustments), a moderate application of the brake pedal will hydraulically re-center the piston and automatically turn off the warning light. THE VALVE SHOULD NOT BE DISASSEMBLED TO RESET THE PISTON.

Proportioning Unit Operation
The proportioning valve section operates by transmitting full input pressure to the rear brakes up to a certain point, called the split point, and beyond that point it reduces the amount of pressure increase to the rear brakes according to a certain ratio.

Thus, on light pedal applications, approximately equal brake pressure will be transmitted to the front and rear brakes, while at higher pressures, the pressure transmitted to the rear brakes will be lower than to the front brakes to prevent premature rear wheel lock-up and skid.

If hydraulic pressure is lost in the front brake system, rear brake system hydraulic pressure moves the brake warning switch piston and opens a bypass in the proportioning unit allowing full rear brake hydraulic pressure.

Hold-Off Unit Operation
The hold-off valve section holds off pressure to the front disc brakes to allow the rear drum brake shoes to overcome the return springs and begin to contact the drums. This valve keeps the output pressure to the front brakes in the 3 to 30 psi range until the hold-off pressure is reached (117 psi) and then blends back to give full output pressure to the front brakes under heavy brake applications. This feature helps to prevent the front brakes from locking under light pedal application when driving on icy surfaces. The holdoff valve has no effect on front brake pressure during hard stops.

(more to follow, next post)

Rafa

Thanks for the detailed advice.
So please let me know if I am correct with my assumption but since I have bled the brakes thoroughly and correctly and the pedal now seems nice and firm (i.e., no air in system) It seems you are suggesting that I take it out and slam on the brakes a few times to recenter the piston in its bore within the porportioning valve.

OR if this doesnt work, investigate the rear brake system to be sure it is operating correctly. I am assuming it is because visual inspection and feel from driving the car seem normal. Rears are not leaking from wheel cyls nor are they locking up prematurely or making any squeaking or grinding noises. Also, it appears that Granny had the brakes gone over a short time before she passed and left the car to us.

A third alternative is to check the emergency brake shaft switch to make sure it is not stuck on.

Final options

? Is there a reset function on the porportioning valve for a 76 manual brake volare? I havent had a chance to check the shop manual yet.

? how much air in the system does it take to trip the light? I am pretty sure I have bled all the air out as I followed proper proceedure and bled MC and each wheel until no air bubbles emerged from collector jar. I doubt this is the issue now but still am curious as to the amount of air needed to trip switch.

Thanks again for the detailed advice

-DW

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Dr Wheelie

Clean all dirt and foreign material from the cover of the master cylinder to prevent dirt from falling into the master cylinder’ reservoir when the cover is removed.

(Complete bleeding of the dual master cylinder is important! See Bleeding the Master Cylinder in this Group.)

Starting with the right rear wheel clean all dirt from the bleeder valve. Place bleeder hose on the bleeder valve and insert the other end of the bleeder hose into a clear jar half filled with clean brake fluid. (This will permit the observation of air bubbles as they are being expelled from the hydraulic system and also prevent air from being drawn back into the system. Follow the manufacturers instructions in the use of the bleeder tools).

Continue this bleeding operation with the left rear wheel, then the right front and finishing with the left front wheel.

If necessary, repeat this bleeding operation if there is any indication (a spongy brake pedal or warning light) of air remaining in the hydraulic system.

Brake System Bleeding Procedures
All vehicles are equipped with a pressure holdoff valve. The valve is located (in the combination valve) on the left side of the engine compartment. The use of the hold-off valve is to better match front disc brakes with the rear drum brakes, resulting in improved braking and steering control on icy surfaces.

Due to operating characteristics of the valve, which causes complete shut-off of the flow of brake fluid between approximately 3 and 135 psi, front brake bleeding procedures should be done as follows:
(1) Gravity Bleed: This method of bleeding is not affected by the hold-off valve, as fluid pressures are always below 3 psi. Remove master cylinder reservoir cover and gasket, then fill reservoirs with approved brake fluid. Open disc brake bleeder screws, and allow fluid and air to drain until stream of fluid is free of air.
(2) Pedal Bleed: This method of bleeding is not affected by the hold-off valve, as fluid pressures are in excess of 135 psi. Follow normal procedure of pumping pedal and opening bleeder screws. Do not pump master cylinder dry!
(3) Pressure Bleed: This method of bleeding is influenced by the hold-off valve. Bleed pressure, normally about 35 psi, is high enough to cause the hold-off valve to close, stopping the flow of fluid to the front brakes. However, the valve (Fig. 2) must be held open manually by using Tool C-4121, to pull the valve stem out.

CAUTION: Under no condition should a rigid clamp, wedge or block be used to depress the valve stem, as this can cause an internal failure in the valve, resulting in complete loss of front brakes.

It should be noted that the pressure release valve stem is in its innermost position when there is no pressure present. No attempt should be made to further depress the valve stem.

all of the above and much more can be seen at http://www.dippy.org/main.html

Have fun

Rafa

No Doc, you do not have to go out and slam on the brakes. Just turn the ignition switch on and make sure the parking brake is off ( the light goes on with the parking brake on) and reset the the switch piston with moderate pedal force.
Just step on the pedal and hold it for a while. You may hear the piston "click" when recentering and putting the light out when you apply the brake with moderate force...
Now if this doesn't cure your light on situation, then your parking brake switch is not working correctly or is permanently on.

Rafa

I am not a fan of the bleeding the brake fluid into a jar routine. Since I have never had a pressure bleeder, I have to use an assistant(usually my wife or one of the kids). The brake pedal assistant needs to be attentive and not be timid about applying pedal pressure to the brk pedal. Simultaneous with you opening the bleeder, the assistant must jump on the brakes and hold the pedal at full stroke until the bleeder valve is closed. The actual bleeder wrencher should watch for spurts of air mixed in with the expelled fluid, and not allow the assistant to release the pedal until the valve is fully closed, otherwise you'll suck in air into the system. He also has to be watchful to make sure the reservoir remains sufficiently full, or risk reintroducing air into the system that way.
If the shoes are properly adjusted, you should not be able to 'raise the pedal' by pumping the pedal. If the pedal comes up at all, by pumping, there is still air in the system.
I've tried that 'jar' method, and found it to be less than satisfactory.
My method is a little messier, but I've used it litterally hundreds of times without a problem. It also uses more brake fluid, but brk fluid is cheap, and should be changed every couple years anyway.

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'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

Sounds like a good bleeding routine.
I have had to do most of the work on my own so I have used a one man bleeder like you get at autozone. It is basically a sealed bottle with a magnet on it and a tube that goes to the bottom of the bottle. There is then a line that connects to the brake bleeder. You hang the bottle by the magnet and then stick it on the inside of the car above the bleeder nipple.

I bled the m/c and then each wheel. I made sure to check the resevour often to make sure that the fluid level didnt get below the openings in the casting. The pedal feels pretty darn firm, however it is the case that if you really push it hard it gives a bit, kind of loses its resitance. Then I pump it once or twice and it gets nice and firm again for awhile.

I am assuming there is still just a bit of air in the system but honestly the brakes feel better than ever and are stopping the car very effectively.
If there is even a small amount of air left in the system is it enough to keep the light on?

I will know more tomorrow when I begin to troubleshoot the many possible solutions to the problem. If none of these work, I will rebleed the whole shooting match using your system

Thanks
DW

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Dr Wheelie

What about those one man bleeder screws?