Manual Brakes brake pedal?

[Jicaju]

Sack's I got my pedal out today and your calculations are spot on. I ended up drilling my hole 2 1/4 below center point of upper pivot pin. This will give me a 6:1 ratio. I have Aeromotive brakes on all wheels. They recommend a 7:1 ratio, but that is with the 1 1/8 bore diameter master cylinder they sell. My master cylinder came TRZ but the instrutions in MC package were from Strange Engineering. The instuctions with the master cylinder said for a 1.125 bore master cylinder ratio should be 6.5:1 and the 1.032 bore diameter master cylinder (like I have) ratio should be 5.5:1 ratio. So I just went between to 6:1 ratio. I just welded up orignal hole and redrilled because they were close together.

Powermaster pedal length from center pivot hole (top) to center pedal pad= 13.5 inches
Powermaster pedal length from center pivot hole (top) to center push rod hole (after removing)= 2.75

thus 13.5 divided by 2.75= 4.91:1 ratio
for mine 13.5 divided by 2.25= 6:1 ratio
yours 13.5 divided by 2.125= 6.35 ratio

Michael

 

[sackracing]

Haven't driven it yet, but it feels like a normal brake setup now. If I hafta pull that $&@! pedal out again, I'm gonna burn the garage down with the car in it.

 

[gnxtc2]

The PM pedal is close enough ratio. I knocked the pin out and drilled a hole. I also have the adapter plate from drag brakes. The guys at drag brakes asaid install the MC on the firewall and drill the hole in the pedal where the rod lines up.

If you want change the height of the rod on the pedal, the firewall bracket needs to be adjusted. If you raise/lower the rod height, you might bind it in relation to MC bore.

Another thing, match the MC bore size according to the brake components (wheel cylinder/calipers). Bigger is not better here.

Billy T.
gnxtc2@aol.com