Jepcopterpilot made the following indisputable comment on dual master cyclinders causing me to do a 180 on my desire to keep my truck's original brake system.

"Single master cylinder is just not an option that can be used in Southern California Freeway traffic.... must have power dual master cylinder or a very large Insurance policy.... we have almost 23 million people sharing the oldest freeways in the world at 75-80mph..."

I will never return to Calif. home of my birth, hi-jacked by communist, overtaxed and invaded by crazies, but I may drive in OKC. (Not sorry for the political statement. I promise it will be my last one.)

So.... what dual systems have you-all installed lately and at what cost?
Thanks in advance.

 

You have a '62 F100 4X4, correct?

 

Yes, it will be put back together this week so I can easily install the conversion over the next few days.

 

On my '66 F250 4X4, I just unbolted the single MC and bolted the dual MC off of a '74 highboy on. I didn't use the brake booster though.

 

Good info on the 74 easy switch over. Thanks.

Did you just connect the single line system to the dual by use of a Tee or did you run a second set of lines to the brakes, splitting them (front set from the back set)?

The use of a Tee would make it the "next step up" safer to protect from a single master cyclinder piston failure but will not protect against a line failure or slave cyclinder burst.

 

And some follow up questions for discussion:
What size was the old MC bore and what sizes are the bores on the new MC?
And did you use a proportioning valve?
And how is the braking from an easy rolling stop?
And how is the braking from a panic stop?
Can you lock up a std size wheel and tire?

 

You really need to make it a split system. To do otherwise is counter-productive, and actually may not work.

I did not use a booster when I went to disc brakes. The only time I miss it is when I tow the trailer with the race car on it. Then I smack myself in the forehead. Repeatedly.

You need a dual circuit master cylinder for whatever brakes you intend to run. Drum/drum or disc/drum, and manual or boosted. Reason being, these things have bores sized specifically to do the task. I'd also go with half ton vs 3/4 or 1 ton, whatever your truck happens to be, as the piston sizes of the cylinders/calipers may vary also. Since most of the same stuff was offered a few years later on these trucks, it's not difficult to find the right setup from something slightly newer.

Proportioning valve on disc brakes, yes. I can't say if you'd need it for drum/drum setup but I'd seriously consider adding it regardless.

 

All FoMoCo vehicles beginning model year 1967 with dual master cylinders have a Brake Differential Pressure Valve, called a proportioning valve by some.

 

I installed the "prop" valve and lines off the '74 too.

 

Political statements are accepted when true!

 

from a Conservative living in LA LA Land of the communist..... I used a CPP Dual master/Booster kit..... from Classic Performance Products they are SO Cal Local company but their system is bolt on, it is not as cheap as Junk yard parts, but it is a very easy step by step swap, and the kit is tailored to your particular set up... I did mine a few years ago for $275, they now run $299, up $24 in about 3 years, but you have a warranteed part that will more than handle the job, and is quite easily adjustable Drum/Drum kit does not come with a Proportioning valve as one is not needed, but the Disc/Drum, or the Disc/Disc kits do have the Prop valve already installed on the Master... it is a simple task of bench bleeding the new unit, it comes with a kit to bench bleed it, then install, split your lines front and rear,, I went down to the tee, removed the tee and put two ell's in one for either set... and plumbing in the brake light switch... then bleed the complete system and adjust... when I did this I also took the front drums which have a single piston wheel cylinder, and swapped it for a dual piston wheel cylinder... left rear dual cyl fits right front, and right rear fits left front... picked them up for $8 apiece from rock auto.. easy swap... I tow an auto trailer for my sons track car, which is a Subaru WRX twin Turbo.. the truck handles it quite nicely up and down the grade to the desert, it also handles my toy hauler which has surge brakes.... I have no hesitation driving it daily in LA. / OC. traffic. It drives like my 2002 mustang on braking... the Kit is a Late 1970's Corvette Master/Booster with mounting brackets that bolt right on to the firewall... My total install times was less than 2 hours for the master, and splitting the brake lines... Best move I ever made.... very smooth progressive sensitive braking require very little pedal pressure, but also gives great feed back through the pedal... Stab the pedal and all four wheels will lock or you can feather the pedal until they just about start to lock...but you have the choice...

check it out.. it is not for everyone, but it sure takes the hastle out of conversions
Classic Car and Truck Brake, Steering and Suspension Parts

 

Jetcopterpilot, Thanks for the detailed info. I am a bit worried my 223 will not react well to a power booster.

Anyone out there using a booster on a 223?

 

Smaller lower performance engines create a lot more vacuum than high performance engines, due to air flow restrictions... your 223 will have more boost than my built 352.. and mine has more than enough.. general rule the bigger and longer the cam lift, the less vacuum pressure in the intake.. ported polished heads flow much easier consequently less vacuum...

 

I too have a CPP set up and its on my 223 - However I'm not on the street yet so can't give you real world history comments .....Why do you think it "will not react well" ?

 

Maybe you should upgrade to a 262. You couldn't tell the difference from the outside.