4 wheel discs master cylinder

[snipes243]

What master cylinder is everybody using for 4 wheel disc brakes?

[broncosbybart]

I've run the corvette cylinder or the stock cylinders w/out issue. If you are running the adjustable prop valve you have, there shouldn't be an issue with your current one.

[chuzie]

Depends on your booster. If you have a stock Ford booster, the stud spacing is slightly different. Corvette MC is what Duffs put out for a long time with their booster.

[broncosbybart]

Good advice there. I didn't realize that but guess that is why I've used both before...

[Bronco Biff]

....make sure you insure whaterver M/C you run it matches the calipers you have particularly insuring the volume of fluid is adequate. If you try to use a M/C designed for disc front/drum rears or drum/drum you won't get the volume of fluid required to adequately operate the rear calipers.......I've seen 1/16" piston dia differences throw the balance out where an adjustable proportioning valve couldn't compensate to give correct balance or running out of "peddle" before the brakes worked when really laid into...... Vette calipers have four pistons at about 1.8" gm/ford truck calipers have one about 3.2", drum brake wheel cylinders usuual have 2 at around 1.375"......just adding just incase!!

[broncomatt]

There is a bunch of research involved with chosing the correct master for 4 wheel disks. The bore and stroke of the master must be right for the size of the piston. If its too small it wont move enough fluid and you will have a spongy, weak pedal. Too much fluid and you will have a hard pedal.
I put my disk brake kit together with help from Randall Thomass of Performance unlimited who tought me about fluid movement in relation to bore and stroke of the piston and how it affects your pedel. I ended up using a master for a late 70's Lincon that came with factory 4 wheel disks.
Keep in mind you cant use one that is ment for drum/disk combo, it wont move the right amount of fluid to correctly work the pistons of calipers on all 4 wheels. There is a write up in our tech section I did on rear disk conversions.