Help straighten me out on the disc brake upgrade

One thing I dislike about my jeep is the drum brakes. The common reasons could be listed here but you know them. My first Landcruiser had them on all wheels, and my second did not. I noticed way back then that drums dont work well in reverse, i.e., on steep inclines. I have noticed this about my Jeep too so I have concluded, rightly or wrongly, that drums only work well going forward. The application here is an 11" drum brake d30.

I have read the ecj tech page on the brake swap, and other resources, but I still have a few questions. I have read that the drum brake spindle cannot be used, but the wheel bearings are the same. I can only conclude that the bearings are spaced differently on the disc brake spindle; either/or farther from the caliper mount and/or further or closer together. The spacing from the caliper mount and the use of my drum brake spindle is what I am wondering about. Does the chevy mount take this into account and everything work out ok or do I need to get disc brake spindles?

Karl

 

I did the disc brake swap on my 72. I have a dana 30 front axle. The spindle used for drums is different than those used for discs. the inner race on the drum spindle is larger the outer one is the same. the outer bearings are the same as both bearings used in the disc hub. The Inner is larger in the drum. I used a complete knuckle from a later d30 which just bolted up to the axle. I ran into a few problems but I can give you other insight to those if you need.

 

I cheated and found a complete disc brake equiped 1979 Dana 30 from a CJ for a $100, simply swapped everything from the knuckles out, and ended up with a spare set of axle shafts to boot! In this day and age with so many people opting for larger axles, the ole Dana 30's are getting easier to come by, at least around here they are. The spindles were different too by the way, but I didn't take the time to figure out why.

 

There is a fellow local to me that has a '79 d30 for sale. I was thinking of picking it up and swapping knuckles out just like you. Do either of you suggestions on any wear points or extra parts that I should make sure are there?

Karl

 

Mke sure the set up is complete, calipers and all. You probably won't want to use the calipers but you will need them for cores. If you prefer your locking hubs you can swap those over, but make sure you get everything (better yet if your not planning on it gt the whole axle). IF things are disassebled make sure you have the following,
Caliper fork/bracket
Caliper
Caliper wedge and shoulder bolt
Spindle
Hub and rotor assemble w/bearings

I'm thinking thats about it. I'm sure if I forgot something others will chime in.

 

The '79 axle I got was out of an automatic CJ, so instead of lock out hubs it had drive flanges, which are great for a trail fix if you blow a hub.

 

Thanks guys.

Karl

 

Wait! Another question! Does the rotor sit behind the hub on all cj disc brake setups or is it particular to the swap only? does anyone have pics of the tsm brake section?

Karl

 

I think it is behind on all of the stock apps. You will need to drive out the studs to replace the rotors. Sorry I don't have any picts.

 

I converted a '73 drum brake D30 to disc using the GM caliper brackets and calipers. Use 76-77 1 1/8" discs mounted on the back side of hubs. The proper inner bearing for the spindle is: cone LM501349 ; race LM501311 I got those #'s from Nickmil and they worked fine for me. If I were doing it again I'd find the disc knuckles and save a lot of grinding. I also had to make new steering stops as i had to grind off the originals. When looking ofr the calipers, try to find them without the casting that protrudes out for the brakeline attaching point. They reduce your turning radius. Or go with the Ford brackets and caliper. 76-77 1/2 ton. Same rotors as above.