Disk brakes all four corners

[garyanna2]

I have the jeep rear with disks and for a mater cylinder i have a 60/40 split MC. It came as a kit with brake and all  the MC is GM. Can i use this with the disk brakes that i have or do i have to use a new same size bowel disk type MC. Has anyone just used the one like i have with the disk brake combination valve for disk brakes? Just trying to use what i have on hand. The disk brakes use 2psi where the drum uses 10psi but the combination valve should reduce the 10psi to 2psi right? That would let me use what i have? Food for thought.

[Radarsonwheels]

Im not familiar with that MC but usually the difference between disc and drum is reservoir size which isnt a big deal and sometimes drum will have a residual pressure valve to keep 5 psi in the line so the drums dont retract

[Jeff Balazs]

I put a Grand Cherokee rear axle in my truck to get a 3.55 and discs. Used a matching GC M/C because I figured it would be the best fit. It has worked perfectly. Makes sense.

Jeff

[garyanna2]

Makes sense, I have opted to buy a corvette MC because the vet has 4 disks already also bought the combination valve. But the jeep would be the best bet with jeep rear. Thanks  I have the 3.55 rear as well does it work well highway and city? I hope so because its ready to put on.

[Radarsonwheels]

Yeah 3.55 is a good gear. I re-read your original post sorry I must have skimmed the 1st time- I think if there is a residual pressure valve in the MC it will happily push past a 2psi valve in the proportioning valve. I usually do an adjustable prop valve to make sure the rears don’t lock up first. 

 

I have a ‘corvette style’ small diameter dual diaphragm booster and disc/disc MC in mine. It works ok but there is room for improvement.

[Old CWO]

On 8/24/2019 at 7:08 PM, Radarsonwheels said:

Yeah 3.55 is a good gear. I re-read your original post sorry I must have skimmed the 1st time- I think if there is a residual pressure valve in the MC it will happily push past a 2psi valve in the proportioning valve. I usually do an adjustable prop valve to make sure the rears don’t lock up first. 

 

I have a ‘corvette style’ small diameter dual diaphragm booster and disc/disc MC in mine. It works ok but there is room for improvement.

+1 on the adjustable proportioning valve.  They are not expensive and really allow you to dial in the brakes on a non-OEM system.

 

I have 3.55s and 30" tall tires in my truck and don't like it. While it turned down the high speed RPM to a more comfortable level, it's a dog out of the hole now.  I am making changes this winter to remedy the situation.

[Jeff Balazs]

My truck is a 52 B-3-C with a fluid drive. It has a slightly later (54) 230 in it. The 3.55 works OK with this combo except on steep hills. It could use a few more ponies to be perfect. That is something I will address in the future. But for the most part it works fine. It easily cruises at 65 to 70 mph on the freeways here. If I were located in a more rural environment then I think an axle with a 3.77 ratio would be a better choice

Putting 4 wheel discs on this was definitely one of the smartest moves I made during the build. I knew from the beginning that I wanted to use this truck on a daily basis. The entire braking system has performed flawlessly. Zero maintenance too. I won't say it stops just like a state of the art new car.....but it is damn close. And you need that here in heavy SoCal commuter traffic.

Hth, Jeff

[garyanna2]

Thanks Jeff 

I have the axel in and when it cools off a little this evening i will set the pinion angel, and weld it in. The rear had 5 leafs i took out 2 leaving 3, also added 1954 wills shackles . The rear fender sets about even with the top of the tire looks ok but might add one back. i have the slant six setting up front and it fits like a glove thanks to Cliford it has some added power. No cutting fire wall and if the car version is used no oil pan change. I will try to post some pictures for show and tell. thanks.

 

 

 

Edited September 1, 2019 by garyanna2

[goingbush]

Where are you guys mounting your  GM or Jeep Split system master cylinders  for your 4 wheel disc set ups ?     On the firewall with a Vac Booster  or unboosted under the floor on original position ?     Hmm  maybe a dual diaphragm 7"  booster will fit under the floor ?? 

Im thinking about a DCM disc conversion for the front of my '49 Ute & they state they work fine with original MC ,     but Im also thinking of swapping a Jeep XJ rear end  into mine  as my  rear drums are  skimmed beyond safe limits ,   XJ  Drum rear ends are getting a little hard to find so perhaps I should go a  disc YJ back end , but  no way I'll be putting the Master cylinder on the firewall.     

[garyanna2]

I put mine on the fire wall  under the divers side up high. No power booster though.