Disc Brake Conversion '55 CJ5

Hey all,

I have been working on a full restoration of my great grandfather's '55 CJ5 and I have made it to the stage where I am replacing and upgrading the brakes. I opted to go for front and rear disc brakes and ordered the Trackick brackets from Brennan's Garage that allow you to use Geo Tracker calipers and rotors. Being totally new at this and very ignorant, I just had the realization that I will not have a parking brake in my current configuration. I had a friend who knows much more than I do suggest using a brake lock of some type. I also had a few friends just suggest always parking the jeep in 1st gear and bringing wheel chocks with me (which seems a little sketchy). I was wondering if anyone else has run into this situation and what solutions you came up with.

Any advice would be appreciated!

-Alex

alove, this has come up before. I think there was general agreement that in the long run, the original transfer case mounted emergency brake was the way to go.

Stupid Question: Would that work with rear disc brakes or would I need to go with the original rear drum brakes?

The original e-brake works by holding the driveshaft. It is independent of the brakes at the wheel. What is on the back of the transfer case now? Take a picture, lets see whats there.

I pulled the engine and I'm planning to swap in a 4.3L out of an S10, so I'm not sure how that fits in. I believe I will be able to use the original transfer case with this setup, so I'm assuming I can stick with the original e-brake as well.

The 4.3 V6 has the same transmission bolt pattern as the 350 Chevy, but you'll need an adapter to mount the Chevy to the Jeep T18 transmission. (Then you can use the stock parking brake). Advanced Adapter has adapters for just about any configuration one could dream up.

A disk brake conversion will make a huge difference in the braking performance. The parking brake on the transfer case is pretty basic, but effective.

I'm not disagreeing with anyone here and all the advice is sound. However, I'll just point out that me and my Dad drove his 61 CJ5 from 1966 to 1988, almost daily, and never once did we use the parking brake. Mostly because it didn't work and we never bothered trying to fix it because we felt it wasn't needed. We lived in the mountains above 10,000 ft. elevation, so lots of snow and cold. Dad said that transfer case brake tended to get wet or full of snow and then would ice up and cause problems, so he never used it. So, when parking, if you put it into reverse, if you're headed downhill, or 1st if you're headed uphill, you should be OK in most situations unless someone or something knocks it out of gear. Just my 2 cents!

True you could get by without one. On a big hill it may just turn the engine over. You will not be able to idle in neutral on anything but flat road. If you had a P.T.O. or other device that requires the engine to be running in neutral, it would also be difficult. All that being said there are many vehicles running around without a functioning emergency brake. I think it is always best to have one, in case of an emergency!

It’s nice to have a parking brake. I have owned a few vehicles with manual transmissions that didn’t and got used to killing the engine every time I stopped so it would not roll away. I find parking brakes particularly useful at gates and on boat ramps or anywhere you wouldn’t normally want to shut off the engine for a few seconds. I don’t know that I have ever used a parking brake to park where I knew the engine would be off anyway. Bad habit because I have had both manual transmissions in gear and automatic transmissions in park roll downhill.

Our 2A didn't have a functional parking brake for many decades. Now that it works properly, I use it almost every time I fire it up, just to ensure that when it is idling outside the shop, it's still there when I come out to go for a ride. With that being said, I don't use it when it is sleeping in the garage-ma-hall.

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!

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.

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

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.

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!Attachment 9602 Attachment 9603

That looks nice!

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

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.

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.

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.