M/C size recommendation.....

[FLYNAVY53]

I'm finally admitting defeat with the power brakes on my '72 C20 Suburban....15" of vacuum just isn't enough to make the power brakes work the way they should so I'm going to convert to a manual system.

I'm using dual piston Wilwood D52 calipers front and rear. The piston area on the fronts are 6.28 in and the rears are 2.46 in. I'm also going to swap in Wilwood's 7:1 ratio brake pedal because the factory pedal is somewhere in the neighborhood of 5:1. My question is what is the appropriate master cylinder size for those calipers with a 7:1 pedal?

Thanks.

[nickburns31]

I would call Wilwood direct. They are great to deal with and they set up my car with the right bore sizes to work with my system.

[65 drop top]

I would guess 1” bore for a 6.28” caliper with a 7:1 pedal. I’d confirm that with Wilwood though.

[FLYNAVY53]

Thanks guys....I sent them an email the other day...usually takes them a few days to get back to you, but they're generally pretty good about it.