C3.....Brake pedal/switch problem

[bruce11495]

I just had the power booster overhauled, nothing else was touched or changed. I just removed the booster, didn't do any other work under dash.
I now have a problem getting the brake switch to work. I'm about 3/8-1/2" short on having the brake pedal touch the switch to shut off the brake lights. Right now the lights stay on and the switch is at it's limit of adjustment. I never altered the switch adjustment on removal of the booster.
I already took the booster back to the guy who overhauled it and he took it apart again, and we could find nothing wrong.
I'm stumped as to what measurement has changed.....Thx in advance

[Chuck S.]

Re: C3.....Brake pedal/switch problem

Bruce, did you try adjusting the clevis at the brake pedal for correct free play; i.e. pedal movement before the brakes are engaged? My 70 AIM indicates there should be 0.25" free play. Also, it sounds like you removed the master cylinder from the booster without breaking any lines, and the system does not need bleeding. If not, the system would need to be bled before checking the linkage adjustments.

[bruce11495]

Re: C3.....Brake pedal/switch problem

Chuck....There is no adjusment on the clevis end. It shows that there should be an adjustment in the service manual, but there is none on mine.
You are correct assuming that I did not break the lines when I removed the booster. Would this make a difference in the free play?

[Chuck S.]

Re: C3.....Brake pedal/switch problem

Effect on freeplay? Probably not, but no final conclusions should be drawn on the brake system until you have a firm, full-height pedal. If you haven't broken the lines, air probably isn't the problem.

If there is not enough adjustment left in your clevis, there must have been a change in the booster with the rebuild. Do you suppose your technician somehow got the wrong repair kit?

[bruce11495]

Re: C3.....Brake pedal/switch problem

Chuck.....Having seen the unit apart, I don't think the repair kit will affect the peddle height.
I was thinking that he might have got the clevis rod mixed up/misplaced or somehow changed, that is my only thought. The only other way is to look at a similiar unit to take some measurements or if someone on the board has a unit out of the car that responds here that could take a measurement on the length of the clevis rod