They were redesigned completely when the dual piston calipers were added

Your best bet, like has been mentioned, is a wheel cylinder upgrade for the rears. $20 and a few hours of your time. The jury is still out on what cylinder to use in a 1/2 ton though....the 1 Ton Chevy Dually cylinder or the 1 Ton Dodge cylinder.

 

I did the 1 ton GM cyls back in May, they have helped a bit when pulling the boat and 6x12 trailer. Just thought I might do something more to take advantage of hydraulic theory.
Swapping in a p-valve from something that has bigger wheel cylinders or rear discs ( 3/4 or 1 ton perhaps), changing the master or finding calipers with bigger pistons in the front.
Just thinking out loud, theres alot of variables. If I remember correctly, there was two sizes for the rear shoes, maybe I got the smaller ones.
I don't need bigger tires but it would be nice to have a little more brake when towing a car or something. Never fails, someone pulls in front of you when you're loaded.

I'm always amazed what people figure out when they have alot of time on their hands and access to a boneyard. My buddy has a Cherokee and there's at least 3 ways to put rear discs on his that I probably never would have thought to try. These forums are full of poeple that are very intellegent. I got a ton of info from the TDR and Dodge-Diesel.org.

A while back I saw 1 ton GM aluminum drums mentioned. Whats the scoop on that. Also whats the deal with the Hydroboost, other than what I really need a CTD.



I like to fix stuff, so I drive a Dodge

 

ive read once or twice swapped master cylinders from a heavier duty truck... but doesnt your vacume stay the same amount so there for it still would be limited.. i dunno... just doesnt make sense to me that much

 

Well the vacuum wouldn't change since the booster is the same. The fluid volume would increase at the expense of line pressure because the size of the master cylinder piston has increased. I would then need to push harder on the pedal.
For '95, the master cylinder for a 3/4 ton has a bigger piston, but it also had slightly larger wheel cylinders (1 1/16" vs. 15/16")and the caliper bores are 3.15" vs. 2.94" for the 1/2 ton. The GM wheel cylinder are 1 3/16", so if I were to swap to a different master (larger piston) I would be moving more fluid to all 4 brakes, but at reduced pressure. Since the bores of the calipers haven't changed, the front brakes would effectively become weaker. Thats why I'm thinking it's a balance issue at this point, something that might be changed with different p-valve pressure. I also think the original brakes would work better if the piston on the master were 1/8" to 1/4" smaller, perhaps the stroke wouldn't be long enough though. Once I figure this out, I'll still be hampered by small brake pads.

I need to determine how much pressure and how much volume each wheel brake needs to get the feel I'm looking for. This is where I run into trouble since I'm no hydraulic engineer.

Here's what I'm working with.
The area of a piston is: pi times the radius squared
I've listed the diameters of wheel cylinders here, remember there's two pistons in the cylinder


1/2 ton .9375" r= .46875 so 3.14159 x 0.2197265625 = 0.690290771484375 sq in per piston
3/4 ton 1.0625" r= .53125 so 3.14159 x 0.2822265625 = 0.886640146484375 sq in per piston
GM 1 ton 1.1875" r= .59375 so 3.14159 x 0.3525390625 = 1.107533193359375 sq in per piston

Master cylinders

1/2 ton 1.125"
3/4 ton 1.25"


calipers
1/2 ton 2.94" - area is 6.788661831 sq in
3/4 ton 3.15" - area is 7.79310669375 sq in


Does anybody know how to determine appropriate pressure balance f/r using a factory p-valve?