Disc Brake Conversion '55 CJ5

[alove]

Sounds like the original e-brake will totally work for my set-up.

Follow up question: If I stick with the front and rear disc setup, can I still use the stock hardlines? I am assuming I will need a proportioning valve specifically for disc/disc setups. Can anyone point me to a good option for a proportioning valve? Or a thread that covers this for disc/disc setups?

Any advice is appreciated! I know next to nothing and I am rapidly trying to educate myself, so I appreciate any advice or information!

[bmorgil]

TJones has great experience with disc brake CJ's. He might jump in here. There are a few places that sell Disc Brake conversions. The technical staff at those places are a great place to find out how best to set it up. You definitely will need a proportioning system of some kind. Typically you will use a two chamber master cylinder. It will require new lines. The rear discs are usually much smaller in size. This is because the front brakes do 90% of the stopping. The balance between the front and the rear is called the "Brake Biasing". Too much rear brake and the vehicle will spin out of control under hard braking, quickly. For this reason most totally custom brakes usually use an adjustable proportioning valve.

[alove]

What are the thoughts on this setup:
The kit that I bought from Brennan's Garage allows me to use calipers, pads, and rotors from Geo Tracker front disc brakes on all four wheels with Chevy S10 flexible lines. I found a dual reservoir master cylinder for use with disc/disc front and rear brakes from Kaiser Willy's (link below). I will probably have a friend help me flare and bend some stainless steel hard lines. Am I missing anything? Does this sound like a rational system?

Link for master cylinder: https://www.kaiserwillys.com/disc-br...3a-3b-5-m38-a1

[bmorgil]

It sounds like you are on track. I would call Brennan's Garage and ask them what proportioning valve set up they recommend. If they don't know, something like this will work well.

https://www.summitracing.com/parts/s...8aAoraEALw_wcB

When you get it completed, take it out and lock up the brakes. The fronts should lock first and the rears should barely lock if at all. Adjust your bias accordingly with the valve. The front calipers from a Geo on the rears of a CJ will lock first without a valve.

One quick note. Many don't realize the bleeders on the calipers must be positioned to the top. If the bleeders are on the bottom you will never get the air out, even with a pressure bleeder.

[alove]

Thanks for all the advice! I just got the calipers and pads in and I have the brakes installed (with bleeders up)! I am opting to wait on purchasing a new master cylinder/proportioning valve setup and waiting on the brake lines until I have everything with the engine sorted out so I will have a better idea of what kind of clearance I have and what obstacles I will need to bend around. Thank you for all the advice!IMG_5184.jpg IMG_5186.jpg

[LarrBeard]

That looks nice!

[bmorgil]

That looks great! That is going to pop your eyes out when you hit the brakes.

[gmwillys]

You'd be surprised to the amount of times ones sees where the bleeders are on the bottom.

Looks great! The stopping ability will be a night and day difference.

[51 CJ3]

There must be a way for the air to get out. Not much help here but disc brake bleeders are always on the bottom in airplanes because the brakes are pressure bled from the bottom. Just push fluid in the bottom until nothing but fluid comes out the reservoir. Lots easier than pumping pedals, especially when working alone. Is there any chance the people installing bleeders on the bottom in jeeps are bleeding from the bottom up? I don’t know how I would rig a catch bottle but I expect it could be done.

[bmorgil]

Cant be done that way in the automotive world Jeff. The systems still require the air to be pushed from reservoir to the bleeder and out. There is only one way to insure the trapped air will be removed and that is to force it from the reservoir through the bleeder which if it is not on top, wont let all the trapped air out.