Disc brakes for ol yeller

Hit the junkyard today and realized part way through the tear down of an '83 cj7 that I should have looked for, and read, a disc swap write up before I got to the junkyard, instead of trying to remember what the one I read a few months back said. So I did not keep the five bolt hubs, or the distribution block (proportioning valve?) . I took knuckles, spindles, calipers and mounting brackets (what the hell size are those allen head bolts in the caliper?), backing plates, and master cylinder. I assumed I didn't need the proportioning valve because I grabbed the master cylinder, and I assumed the hubs on the '73 will work with the disc spindles? I also didn't grab the brake lines. I bet they would've mounted right up.
Here's a pic of the junkyard haul.

 

I did the same thing. I have a 73' D30 and used 85' parts. All you need is knuckles, calipers, and rotors. Everything else from the 73' axle can be reused. You will however need to machine the hubs so they will fit flat behind the rotor. Longer lug nut studs will be needed along with that proportioning valve you didn't keep.

 

Ok thanks for replying. I finally got some time to try and read up on other peoples swaps. Seems like everybody does something different. Anyway, I have to take the rotors back to the junkyard and get my money back for those. Hopefully the cj7 will still be there an I can get that proportioning valve. I think I might be able to machine the hubs myself on some night shift. My machining skills are lacking but I can probably manage that. I kept the CJ7 lug studs under the assumption that they would be long enough.
So you put your hubs behind the rotor?

 

The rotor goes on the back of the hub. I'd suggest getting the outer axles from the axle you got the disc brakes from. The disc brake outer axles are different than the drum brake units and match the spindle you are using.


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If he uses his old 6 bolt hub and spindle he won't need the outer axle. I only needed three parts. Rotor, knuckle, and calliper. Ok 4 if you use the dust shield. All his old part can still be used. If you see what i'm saying. Also needs to fab brake lines.

 

The seal surface (dust shield step) on the disc and drum stub axles are different diameters. If he uses the disc brake spindles shown in his pic the seal surface on his drum brake axles will NOT seal properly against the back of the spindle.
The drum brake axle and spindle use a seal that presses into the back of the spindle to keep dirt and debris out. The step on the axle rides inside this seal and is a smaller diameter. The disc brake spindle and axle uses a rubber "V" seal that stretches tight on the step on the stub axle and rides against the back of the spindle. They don't interchange unless you can find the very hard to find smaller V seal used on some open knuckle Scout 30's.
I'm guessing you used the drum brake spindles with the drum brake axles? In which case everything is matched but gives a slightly weaker spindle. No big deal for most.


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Yes. This is what I meant.

 

Interesting. I wondered why some people were using the stubs from the donor and some weren't. Anyway, I'll see if the axle shafts are still there and buy them if they aren't too much. They used to only charge 28 bucks an axle. Hopefully they haven't gone up much. But if they aren't still there, this dana 30 isn't going to see hardly any hard wheeling use so I guess the drum spindles/stub shafts will be fine.
Thanks fellas!

 

Went and got the proportioning valve today. I didn't get the axles so from what is written here, looks like I'll be using the drum spindle and stub axle. It also looks like all these parts are going on a shelf for awhile. I'm going to be busy trying to get my house ready to sell. Sure is nice that my girlfriend leaves her Jeep at my house. I might go crazy if all I have to think about and work on is my house. I much prefer the Jeep.