brake light switch question

[hotrod351]

i just installed a rebuilt power brake booster on my wifes 70 mustang. the biggest problem i had was the stoplight switch working, it wouldnt. i installed the white plastic shim and the black plastic bushing and then the switch and the outside white plastic shim then the retaining clip but no matter what the brake light switch wouldnt work. all i could figure is that there was no movement in the rod coming out of the rear of the booster that hookks to the pin on the brake lever,, seemed that there had to be enough free play to let the booster rod push back and depress the stoplight switch. i tried everything i could think of and finally took out the bushing, that gave it enough play so when you push the pedal down it moves back and works the switch. is it that the hole in the booster rod should of been bigger to alow for enough play to push back and work the switch. what am i missing.

[bears4ever]

I'm not sure on this one. I have a 68 that I upgraded from standard brakes to power brakes. I had to change the stop switch as there are 3 different kinds. manual drum brakes/front disk(non power)/power front brakes. If you upgraded this could be your problem. Could also be a sticky switch that requires more pressure to activate. With my new switch I just touch the switch and the light would go on. Just a thought.

[hotrod351]

found out what the problem was. there are at least two different type of brake light switches, a switch that mounts on the brake lever under the dash and is trigged by the free play in the power brake booster where it connects to the brake arm pin, that also is where the switch is mounted, and the other type of switch which is a pressure switch which mounts in the brake line and is worked by pressure. the booster rod for the pressure switch type fits tight on the brake arm pin and the mech. switch booster has a little larger hole to let the arm move backwards and put pressure on the switch when you push the pedal down. they sold me the earler type. i figured the only way for the switch to work was if the booster rod were able to push the switch in and the only way it would do that was to have enough free play in it to do so. i also checked with a old time mech. and he told me that was a common thing that happened when replacing the booster on the older mustangs so they would just leave out the plastic sleave and that would give the rod the play it needed. if i would of thought ahead of time id mic. the inside of the old booster rod hole and compared it to the new one. anyway it works now. ofcourse the next day one of the rear wheel, cylinders blew out. i already had new rear wheel cylinders and brakes sitting to put on but figured i could wait a week, figured wrong. i went ahead and bought loaded front calipers to put on tomorrow. thanks for the reply.