Power Brakes - Pedal Height
 

How far off the floor should the brake pedal be in '69 GMC with power brakes? I'm installing a booster in my truck and in my first attempt the pedal seems too close to the floor and the brake light switch doesn't reach.

Re: Power Brakes - Pedal Height
 

I went from manual brakes to power disc on my 68 using 72 gmc sierra parts.....my brake pedel is closer to the floor than my clutch...wtf it works but looks funny....i had to adjust brakelite switch also...MAJOR PITA

Re: Power Brakes - Pedal Height
 

Did the same on my trucks and extended the clutch link as far as I dared to. Some guys actually extend the link by adding a section to it.

Re: Power Brakes - Pedal Height
 

Mine isn't like that. I'm wondering if your pushrod that is in the booster is too short. They do come in different lengths. (Actually my brake pedal is higher than my clutch.)

Re: Power Brakes - Pedal Height
 

oh when i swapped to power brakes i used the power brake rod also.

Re: Power Brakes - Pedal Height
 

done a bunch of drum/disc conversions. The adjustment under the dash is for pedal height only! If you have a bunch of slop in the pedal before the brakes engage, you have too much clearence between the booster/master. It does not take much between these to to have a BUNCH of slop 1/4" is a ton. Most kits for our trucks, also tell you to drill a hole about 1" lower that where the manual brake hole is. Do this, and then adjust the rod until the brake pedal is where it was before you started working on it. Mine is exactly where it was when the General built it, and if you do not pay attention ( sometimes I don't ) it will darn near throw you thru the windshield! I believe, that if you go to the tech pages on CPP ( I have never used their stuff ) that it will repeat what I have just said.

Re: Power Brakes - Pedal Height
 

Just got the truck going. The push rod is adjustable, so I set the height a bit lower than the clutch. I just drove it, though, and I think a bit lower is better because when you raise your leg that high to step on the brake you tend to step on it too hard. Setting the brake light switch is a major pita!

Re: Power Brakes - Pedal Height
 

that is the exact reason the pedal is supposed to be lower. There is supposed to be 2 holes on the pedal arm for the pushrod. One is for manual, one for power.

Re: Power Brakes - Pedal Height
 

I heard that, but mine only has the one.

Re: Power Brakes - Pedal Height
 

need to check that then.........

Re: Power Brakes - Pedal Height
 

most aftermarket kits that have instructions that are worth a crap , will tell you to drill a hole in the brake pedal about 1" lower than the manual hole. This changes the fulcrum point??? If I said that right. Like Longhorn man said, IF you had a hole an inch lower in your pedal, and had MANUAL BRAKES, I bet it would be a bear to stop. With power brakes, a hole a bit lower, changes the fulcrum, to " tune " the brake pedal to the power assist.

Re: Power Brakes - Pedal Height
 

With manual brakes the upper hole is used to increase the amount of leverage that the pedal exerts upon the push rod. Power brakes require less "leverage" due to the power assist and thus, require the use of the lower hole. If you use the upper hole and a power booster, you may have very sensitive brakes that grab too easily and are hard to modulate.

Re: Power Brakes - Pedal Height
 

i found that adjusting the push rod is a bad idea if the only issue is pedal height. when you install the mc you want the mounting to the booster to sit flush with no pressure on the mc. if you have pressure on the mc you will pressurize your system leading to the brakes having pressure with no return of pressure. essentially the breaks will lock out and will not allow pressure to return to the mc, you will burn your brakes, end of sentence. adjusting the pedal is a pain but i would say much better than the alternative. easiest way is the unbolt the column from the dash, loosen the bolt from the treaded rod attached to the pedal and adjust the pedal height that way before adjusting the push rod. i hope this will be helpful. adjust the push rod was a major mistake for me.