We can't seem to get the "brake" idiot light in the dash cluster to turn off on our 70 skylark. A friend told me that it is because the proportioning valve in not "centered" (whatever that means), but he forgot how to remedy the situation. Is he right? What must we do?
The prop valve has a differential switch. If there is more pressure on one side of the valve than the other, the light will come on. The switch needs to be centered in the valve for the light to stay off. Also, dont forget the E brake pedal mechanism has a switch on it. If the pedal is loose, it could turn the light on. Pull up on the pedal and see if it turns off.
I assume you figured out that its the prop valve and not the e brake switch? The problem is that there is a difference in brake pressure between the front brakes and the rear brakes. When you bled the fronts, did you hold the pin in on the hold off valve? If not, re bleed the fronts while depressing the pin on the prop valve. You dont need to remove the rubber boot. Once the brakes are bled properly, step on the brakes a few times real hard. You need to generate about 450 lbs of line pressure to re center the differential switch.
I might be having this same problem, I can stop ok, lock the wheels, but my pedal seems to have too much travel. When I press hard the brake dash light comes on. Any ideas?
I removed and rebuilt 1 rear wheel cylinder. I couldnt bleed it through the bleader valve though. had to blead it from the line as the bleader valve was broken off by someone previous to me. From another post here on the forum thats probably my problem because all the air wasnt removed.
