New MC and Prop valve equals light issue

[Mickm69]

Hello all,
I have just installed an ECE disc brake conversion on my '69. I had no issues until I plugged the electrical brake wire cap (brown wire) on the new prop valve and now my brake light stays lit.
The brake, turn signal lights all work correctly. If I unplug the brown brake wire the light goes off.
Can anyone shed some light on what my issue could be?
All help will be appreciated.
Cheers!
Mickm

[Stocker]

Press very firmly on the brake pedal a few times. The switch in the prop valve should re-center and the light will go out.

[Mickm69]

Thanks for the tip Stocker but I tried that and no joy.
What next?
Cheers!
Mickm

[Mr Handy]

sounds like you have a light problem.
Crall under dash,
locate proper light,
turn light boot 1/8 turn and remove light
problem fixed...

sorry, but I have actually seen shops follow these steps... A friend had a light that they could not fix after several trips in, so they pulled the light bulb... he put the bulb back in and made a little paper that said everything's fine and put it in front of the bulb, so now when the light comes on it says everything's fine.

[TBONE1964]

Let me make sure I get this straight:

The light only comes one when you hook the brown wire to the prop valve?

You have bleed the brakes and have a good pedal and there are no issues with the brakes?

The brown wire has to find a ground for the light to come on the dash. It is possible the switch in the new valve is bad or the switch is off center finding a ground inside the valve.

[ChevyCruizer]

prop valves can get stuck in a position that turns the light on. As mentioned above you need to get it to recenter. I usually open the bleaders on all 4 wheels and bang on the prop valve. Sometimes it centers right away but other times I have had to get out the big hammer. But if your stuff is brand new it should center right away.

I just replaced a leaky master this weekend. After the replacement I gravity blead the system and had good drips out of each wheel. But when I took it for a ride it didnt feel right. So I had to get the wife to help me pump while I cracked each bleader. The back had no pressure. So I had to open all 4 and really work the prop valve with the big hammer. Finally, it reset and then I got good pressure to the back wheels.

Found this:

Fluid from your M/C flows through both ends of this thing. Your front lines through one end, and the rear through another. Inside is a plunger, right between the 2 fluid lines. As long as both front & back hold pressure the plunger stays centered. If you get a leak in, say the rear, the pressure from the front lines push the plunger to the rear (low pressure) and seal off the rear lines and trip the light in the process. The switch is in the center, you can see the wire attached.

Now the trick is to get that plunger to move back to the center. You are getting close by pressurizing the rear but you are putting air in the system and can make for more problems.

After you repair what ever cased the fluid lose in the rear circuit, you then get setup to center the plunger. This works much better with someone inside the truck while you use a wrench on the lines and give instructions.

Turn the ignition on and have your helper watch the brake warning light, if it goes off, stop what you are doing and close off the lines, the plunger is centered!
With the M/C topped up and the lid on, locate where the front line enters the valve, one of those lines entering from teh top, in the second photo. Crack it loose and place a rag over the fitting so you don't spray brake fluid all over yourself and the truck. Now have you helper slowly press the brake pedal down. Listen very carefully for a click. That is when your helper must stop immediately or the plunger will get pushed over center and will block off the front brakes. These valves can be very sticky and may not move with just an easy push of the pedal. If this doesn't work with a few tries, instead of pushing gently, have them stab the pedal, not too hard, but with a good sharp jab. Close the lines and have them press gently, is the light still on? You will need to try to use the brake fluid pressure to move that plunger. If you move it too much you will need to loosen the rear lines and move it the other way. Often you go back and forth until you get the feel of how hard to hit the pedal.

Once you get the plunger centered the brake warning light should go off and you can finish bleeding. When bleeding always go easy with the brake pedal. Remember, you are creating a fluid lose in on of the brake circuits, and one of the proportioning valve's job is to prevent fluid lose by closing off that circuit.

[cdowns]

the proper way to bleed these brakes is to clamp the pin to keep centered and warning light off

for in detail explanation just read a factory service manual 71 or 72

[Mickm69]

Thanks for all the input guys.
Yep, I have bleed the brakes (old fashion way with someone pumping the pedal). I have good pedal and good brakes. The light only comes on when the prop light plug is attached.
I will try your other suggestions.
cheers!
Mickm