Four wheel disc brake master cylinder?

[dieselbronco]

I am running ford disc calipers in the front and s-10 calipers in the rear. Currently I'm running a 79 f-150 master with a hydroboost. I'm wondering if there's a better master for my setup and what every one else is running?

 

[Apogee]

What type of hydroboost are you running? Ford Mustang or Superduty? GM? The Mustang units are somewhat special with respect to the master cylinder mounting pattern being vertical instead of horizontal, they also don't produce as much gain as most of the other units.

As for master cylinders, most would run a 1-1/8" bore MC with a GM hydro unit and the calipers that you have front and rear as it provides better modulation and a higher/firmer pedal than the 1" (probably) bore MC you currently have.

If you have an issue with the feel or performance of your brakes, why don't you share that with the rest of the class so we're not just guessing as to why you're asking the question. Who knows, it might be pertinent.

 

[Past_Miner]

Since you are running the 79 F150 master I am going to assume that you are running a Ford hydrobooster that fits that cylinder as well. I use a disk-disk master cylinder from a 77 Lincoln Continental with my booster. It has a 1 1/8" bore and has the proper lack of residual valves for rear disks. If the F150 cylinder fit your booster without modification this one will too. My rear disks are from an Explorer and the master sends way too much fluid to the rears so I also have an adjustable proportioning valve in the line to the rears to balance my braking. Without the proportioning valve you are likely to lock the rear brakes up before the fronts really start to grab, especially with a hydrobooster.

 

[dieselbronco]

Sorry, I should have elaborated some more. The booster is from a super duty and I made a mistake with the front calipers they are t-bird calipers. My problem is mostly feel. A little to soft and squishy. Never a problem with stoping or locking up the wheels. ( plus no proportioning valve ). The other problem is the top sealing surface of the mc gets rusty and starts to leek, so I would like to find a aluminum mc with a plastic res.

 

[Apogee]

You could run the 99-04 SuperDuty master cylinder...aluminum body, plastic reservoir, screw-on cap, 1.375" bore. It came with ~13" rotors, however the piston areas of the calipers are actually smaller than what you're running at 7.06 sq in for the front and 4.98 sq in for the rear calipers.

Your setup with the T-bird/LTD front calipers has about 7.5 square inches of piston area up front and 6.77 square inches in the rear. Given your wheelbase, smaller rear calipers would really work a lot better as you can only do so much with a proportioning valve (assuming you have one), but the larger bore SD master cylinder should make your pedal higher and firmer and make your brakes less senstive. The greater the effort needed at the pedal to achieve lockup, the better your brake control and modulation at the pedal.

Anything larger than the 1" bore unit that you're running now should be an improvement in the pedal feel.

Tobin

 

[dieselbronco]

Thanks for the info.that sounds like a decent option. As of right now I have no proportioning valve. The problem has gotten worse since I took the leaky cadilac rear calipers off and installed the s-10 fronts in there place. Do you think that they are a bigger bore, witch would require more fluid flow and that's why they are softer?