Howdy.
New to this forum, but far from new to Classic Cars and Mods.
I have a 1974 Toyota LandCruiser (bought new), In 1978, as a result of five burned #4 Exhaust valves, I fitted a 1967 Cadillac 429cid V-8 and TH-400 to the LC's Transfer Case to keep the 4wd and PTO Winch. (cured the burned valve problem!)
I am now plotting and planning for a Four Wheel Disk Brake Conversion.
I have all the Disk Brake Conversion info from various 4wd sites, my issue is with
the Master Cylinders.. Yes, plural. I plan on fitting Twin (side-by-side) Single Stage,
High Capacity Master Cylinders (Wilwoods).. One system for the front, one for the rear. I'll use '85 Monte Carlo Front Calipers (single pots) and the '70's Caddy Eldorado Rear Calipers (with E-Brake) [purchased from CPP] sitting on '85 Chevy/GMC 1/2Ton 4wd Pick-up Six Lug Rotors. For cheap insurance, I'll be fitting a 2lb Residual Valve at each M/C. (going up or down steep hills will put the M/C's lower than the calipers.)
The stock LandCruiser Brake Pedal has, to the best of my measuring ability, a 4.5:1 Ratio (had a power booster). Said Pedal has an 18" Overall Length and there is no room to fit a Wilwood 7:1 pedal set-up. I believe I'll have the room to raise the mounting location of the twin Master Cylinders and be able to fit the Wilwood "Bal-Bar" somewhere between one to two inches above the stock pedal's brake rod pivot point, giving me a range of ratio options between 9:1 to 6:1.
Now the sticky part.. I know I'll need small bore Master Cylinders and smaller brake lines to produce around 1350psi (at the M/C's), but just how small? (I'm thinking 3/4" bores with 3/16" lines.. but know of no way to calculate for this.). I need the Applied Brake Pedal Pressure to be equal, or better (less), than those of '50's/'60's era manual brakes, without being "too sensitive" (aka "twitchy!"!).. Something an average woman could easily handle... not a pedal pressure requiring a Sumo Wrestler's strength! Fitting a booster is NOT an option!
Also, I'd like to fit an Adjustable Proportioning Valve on the rear brake system. As a former (motorcycle) racer, I am fond of "Trail Braking" (backing it into the corner) and would like to be able to change the Brake Bias to as much as 30/70 (front/rear), or more, under certain off-road conditions, as well as using a primary 70/30 (front/rear- or more) street setting. What brand Adj Prop Valve is made for a Disk/Disk set-up that will give that range of bias adjustment?
Hate to be so windy on the first post, but it's a detailed, involved and critical subject that one does NOT want to get wrong! ;-}
Any and all help, info and advice appreciated.
Thanks.
Chas.