Manual brake master cylinder?

Hey guys! Just wondering, I'm going to be running a manual brake setup with my LS swap. I've seen a few people run manual brakes, what master cylinder do you guys recommend?

first off, what calipers are you running?

i went through the wringer trying to get my manual brake setup to be acceptable, and im still not 100% happy with it. on my 85.5 944 n/a, first thing i did, as per the ls swap how to, is went with the wilwood tandem 1" bore. it was terrible, i had a hard time stopping the car driving around the parking lot, pedal was rock hard. after playing with the pedal ratio, i found another master cylinder that would bolt up, it was a datsun 510 master cylinder with a 3/4" bore. it was better, but i still didnt feel comfortable driving the car. a had been collecting stuff for a big brake swap for some time (lexus ls430 front calipers, 12.2" rotors, rx7 rear calipers with 944 turbo rotors), i decided to bite the bullet and finish it off. got that all on the car, with the 3/4 bore master cylinder, terrible, had to pump it to get it to stop. went back to the 1" bore wilwood, and thats what im still running. pedal feel is good, around town the brakes feel pretty decent, however im still having a couple issues. one, the car stops decently, however if i step on the pedal, lift my foot and step on it again i have a way firmer pedal and better braking. two, i dont feel comfortable with braking from high speed, it just doesnt seem to have enough power. at any point, i can spike them and lock all 4 wheels up.

i think im one of the few in the last couple years that has played around with manual brakes without going to a dual master cylinder. most people now either just go for hydroboost, or screw around with manual and then go hydroboost, or dual master cylinders. with my swap, neither are good options.

so what master cylinder should you run? im gonna leave you with this calculator http://www.jakelatham.com/radical/info/brake_calculators.shtml#pistondiameters

Sounds like you have air in your  lines if you let of, apply brakes and have a firmer pedal. Is there a tandem option with different sized front and rear MC's? That seems it would be a better option.

there is no trapped air. ive bled it every way imaginable, removed the calipers and rotated them around, etc. what i have niticed is the pistons in the front calipers seem to retract a long way.

Check the wheel bearings for play. If the hubs wobble it will push pads back. Also check to make sure cap is venting. If not it will pull pistons back by vacuum.

already been there, not a knock back issue. i can release the brakes and re-apply them so the pedal is firmer, lift my foot, wait a few seconds and the pedal travels further again, all with the car on jack stands, and with the cap off. i can put the pressure bleeder on it with around 12-15 psi and it feels firmer, much like the 2nd pump.

ive got a thread on my brake saga in the brake section, its titled "manual brakes for 85.5"

Soooooo....anyone else have any bad or good experience with manual brakes?

I had a willwood 1" tandem master cylinder before with ls430 front calipers and rx7 rear calipers and I hated it. It felt very sketchy to get the car to stop. I went with a mustang hydroboost setup and its 100% better.

My advice is.... Don't use a manual master cylinder if you don't need to

What is the purpose of the car? If it is just for occasional street driving, I've found my manual brake setup to be fine. No, it's not as nice as a hydroboost setup, but I've driven lots of cars from the 60s and 70s that had manual brakes and weighed a lot more.

I'm running the 944 master cylinder and braided brake lines so there is less wasted pedal movement. I really don't mind it, though I need to build a brace from the strut tower to the master cylinder mount at the firewall to reduce firewall flex when I hit them.

I wouldn't recommend this setup for a track car at all, but for just easy street drives it is fine. Haven't had a sketchy moment yet, just gotta drive smart and know what your car can and can't do.

Yeah it's gonna be a daily

Oh, I also relocated the location the master cylinder rod connects to the pedal. About 3/4" further up the pedal if I remember right. Gives you more leverage.

Yeah I heard to do that, but if it's for daily street use to do 1.1"

Also where did you guys get the firewall adapter?

I bought mine from renegade hybrids. There is a pretty negative view towards them in this forum, but my experience buying this one item from them was perfectly fine. Adapter and custom master cylinder pushrod arrived within a week after ordering and fitment was good.