[Muadi]

New brake light switch installed. So far, this appears to be the correct fix.

[jrubakon]

I had the same issue and it turned out to be worn brake pedal bushings. I replaced them, readjusted the linkage and have been good to go since. My tail lights would turn on and off by themselves before the fix.

[68RS-SS]

Worth noting that the PB switch is different than the MB switch. I've been using one of those paper binder clips that I clamped on the pedal arm for years to take up the slack since converting to PB. Recently I got the repro. bracket and correct switch. The bracket didn't make sense to me how would fit on my pedal arm. I did notice that the PB switch allows for approx. 1/4" longer adjustment. That was all I needed to call it good & fixed. W/PB a return spring is not needed.

[Muadi]

Well, I spoke too soon. Still having the same issue. The brake pedal seems to hang just before the rubber bumper stop. I have to pull the brake pedal up into position to relieve the pressure at the m/c. Will continue to investigate.

Bill, do you think the bracket difference between pb and mb could be causing this? It seems like the switch would not have enough strength to resist the pedal from full return, but stranger things have happened.....For years all has been fine. I have been having this problem just recently.

[SixtyAte]

Spray lube around the brake pedal pivot pin for starters. Check your vacuum line for the booster and bleed the brakes. All these things can cause your issue among other things....like a bad switch or wrong switch.

Kev

[Muadi]

The basics. Brakes are bled, no air. Pedal swings freely, no binding (brake light goes on and off very smoothly, no binding). Clevis pin is clean, no binding. The binding issue does not occur when cold, only after a drive.

On Sat. I pulled into my driveway, and the brakes were hanging and holding the brake lights on. I removed the M/C. Of course the brakes then released, but the brake lights were still on. I removed the clevis pin, it was under tension. Brake pedal returned to normal position (return spring) and lights went out. I unbolted the vacuum booster, and carefully removed it. I tried to push the input rod in... it had to be pushed pretty hard. I had it facing downward (m/c side on the ground) and I was applying pressure downward. It did not want to depress. A friend of mine put his hand under the booster, and moved the output rod a little. Instantly I was able to press the input rod into the booster. We were able to repeat this. It appears that the output rod can get a slight angle to it, and kind of lock up the input rod. We were kind of guessing, but if there is a bind on the input, then, I guess, there could be a bind when the rod is returning to its rest position. I looked all over the booster, and did not see any manufacture stampings. I'm not 100% sure where it was made, or its brand. It is a 9" (or smaller) dual diaphragm model.

So, I guess my next step is to replace the booster. I did take a look at the input piston on the m/c, and everything looked good. No obvious burrs or scrapes.