Reproduction power brake pedal

[supergluehero]

I'm in the process of putting my parts list together to convert to Wilwood disc brakes and got into the master cylinder sizing. My current pedal has a ratio of 6.7:1 which would indicate that it's a manual brake pedal. From what I've read, the power brake pedal has a ratio of 4:1. I've got power brakes, so I'm assuming the previous owner put on the booster without changing the pedal to the correct one. I'm also putting in a TKX 5-speed from Silver Sport. I spoke with their tech support and they indicated that the pedal the provide in their kit has a 7:1 ratio. All the reproduction pedals I've looked at don't indicate whether they are for power or manual brakes. Wilwood tech support said 7:1 is too high for power brakes and I would need something like 3:1 or 4:1. Am I missing something here or do all the reproduction pedals assume that you're using manual brakes?

 

[Sam69sat]

I don't think there's a difference in the actual pedal. The linkage is definitely different between the pedal and master cylinder on manual vs power.

 

[supergluehero]

Someone on another platform was able to point me in the right direction. There's a pivot linkage that reduces the ratio by roughly half that is added for power brakes. Here are a couple of links for future reference:

Brewer's Performance

Summit Racing

 

[Robert Schaad]

My brake pedal is low. Power brake car. Replaced master cyl and power booster with stock parts. My question is this. On the rod coming out of the power booster there is a nut. By turning the nut counter clockwise that will move it out extending the length of the rod, does that cause the pedal to site higher.

 

[1STMP]

My brake pedal is low. Power brake car. Replaced master cyl and power booster with stock parts. My question is this. On the rod coming out of the power booster there is a nut. By turning the nut counter clockwise that will move it out extending the length of the rod, does that cause the pedal to site higher.

No.
Sounds like you still have some air
in the lines. If your bleeder screws
are below the installed top of the
calipers, the caliper should be rotated
to position the bleeders to the highest
point, bleed the entire system again,
then reinstall the calipers.
Something else to check is the booster
pin length from the pin eye to the back
face of the booster. There's been a
major backlog of parts from major
retailers, and someone sold you the
incorrect parts.