I have an 86' CJ7 w/ 39's. I recently installed Currie Axles front and rear w/ 4 Wheel Disc Brakes. I installed a 4 Wheel Disc Prop. Valve from MP Brakes. I also added a 4 Wheel Disc Master from MP Brakes. At first you had to stand on the pedal just to "kind of" get it to stop. The guy at MP brakes originally gave me a master w/ a 1.125" Bore. He swapped me out to a 1" bore. You can drive it and it does stop o.k., but it is not great. My original set up w/ Disc/Drum was much better. I thought w/ 4 wheel discs this thing would stop on a dime. I had a 74' Bronco w/ 4 wheel drums a 38's that stopped better. Has anyone converted to 4 wheel discs and know of the right master to run. I do not want power brakes, don't like em'. I don't mind spending money on my brakes, so if it is going to be a specialty company, that's o.k. But if you know of a direct bolt in replacement from another vehicle please let me know. If you know the exact donor or part number that would be a big plus. Looking for real world experience. Thanks in advance.

sounds like your master cyl. is still not small enough. The smaller the master cyl's bore, the more mechanical advantage it has over the slave cylenders. why don't you like power brakes? they work wonderfully.

Power Brakes are great except when you lose power and have to revert to manual. It just throws me off when wheelin'. I'm not totally against em', I just prefer manual, always had manual in my trucks and I have become use to em'. They never change regardless of ehat's going on w/ the truck.

Ok the answer is to get vac powered brakes and install a HUGE vac tank that will back up the brakes when the engine is stalled. I wouldn't leave home without em!
Big Jim
Ps. And hey, these liquid powered brakes on my H/D Chevy are beautiful!

if your really really concerened you can get a vacume pump from a GMC/Isuzu mini deisl flat bed and hook it into the vac. reserve. thats pretty much what those trucks run EVERY day for there whole useful life (so far 260K on my brothers)

I run a manual master from a '69 Corvette. It also has a 1" bore and works great with my front and rear calipers which are Chevy truck calipers found on any mid-70s 1/2 or 3/4 ton. I'm running 37" MTR's and it stop better than the disc/drum setup I had on 33's. Many users of 4wheel discs use this same master cylinder. It is exactly the m/c that you see in most 4wheel disc conversion kits. Are you sure that you have them bled completely?

One more thing to look at is the PADS themselves. What you want are the cheapest pads the guy has.. Those lifetime pads are hard and do not stop as well as the softer pads. The hard ones are good for constant stopping as in a race but for general use get the soft pads.
Big Jim

Big Jim come out of the dark ages!

Ever heard of ceramic pads??? They are usually "lifetime" and far outperform the cheapos in braking ability and pad life. Braking is more than just how soft the pad is. Ever heard of fade from heat? Ceramics are affected way less than the cheapos when things get hot. You don't have to be a racer to get heat either. Any place with steep grades to come down can bring that realization.

Howdy CSp
Yep I have heard of em. In fact i'v taken em off to improve the around town brakeing. Lifetime of not stopping well isn't what I'd like to do. Hey once you heat em up they are wonderful... So we stop in the middle of every block, getting ready for the traffic light ahead? Everything has it's place and lifetime ceramic brakes for sure have theirs.
Big Jim

When it comes to 4x4's dont cheap out on brake pads. 4x4's generate a good amount of heat when stopping, something cheapy pads dont deal well with. With ceramic pads, heat is their game, and they play well, with some added bonuses, no dust and squealing. Your problem may be more of a leverage problem. You need help in pushing that pedal down. That means either a longer pedal, or a booster.

Dan