Dana 30 Drum Brakes To Discs

My '71 has a D 30 with 11 X 2 drum brakes. I have a '77 D 30 with factory discs. The '71 axle is 3:73 while the '77 is 3:54, don't want to switch whole axle. What parts other than backing plates, rotors and calipers do I need to remove?

 

The Brake systems don't have any common parts with the gears in the differentials. AFAIK,
as long as both spindles are 27 spline, you should be good to go. I would install new bearings, races & seals , however.

 

Knuckles ?

 

Knuckles to hubs.

 

Knuckles, meaning ball joint removal or just spindles?

 

meaning knuckle and ball joint removal.

 

My understanding was that you swap everything from the ball joints out. I thought the outer axle shafts were different too, but I presume you could use the whole shaft from the disk brake axle.

 

There are some slight differences in the axle assembly as in dust covers.. But not much.

The spindles are different between the D30 disk and drum. The hubs are different in that they are machined flat for the disk. If the disk axle you have is complete, swapping the knuckles over is no big deal. Replace the ball joints while you're at it along with the hub seals.

The 11x2 drums are pretty good though.

 

I think you need to determine which brakes your 77 axle has to know if you need to swap the knuckles. The 76-? had disc brakes with a caliper mounting plate that bolted to the knuckle with the spindle sharing the six bolts - rotors should be about 1 1/8 inches thick. If you have these brakes I see no reason why you would need to swap the knuckles. Somewhere around 77-78 they changed to a caliper which used a c shaped caliper mount which bolted to two ears cast onto the back of the knuckle - rotors should be about 7/8 inches thick. If you have this set up I would agree you would need to switch the knuckles over.

It might be worth considering selling the 77 axle intact and using the 1/2 ton chevy truck caliper brackets to covert to discs. These would bolt on using the six spindle bolts like the earlier jeep brackets.

 

I took a d30 drum and an 80’s wt d30 and swapped the steering knuckles, spindles, and wheel hubs. I didn’t swap axle shafts, you don’t have to remove the ball joints. Just unbolted everything and swapped it over.

 

The disc brake knuckles have a relief cast In them to clear the caliper without grinding. Iirc the clocking of the spindle studs is different as well. Just much easier since he has all the stuff needed to swap everything. Or do the Chev conversion as you suggest.

 

My '77 has the 6 bolts and thick calipers. Another question, will my original D 27 axle bolt on to the '77 so I have a roller. This way I can remove the disc brake axle, put it next to my CJ while I switch parts. The '77 is my parts source.

 

Need to use the GM brake parts. They used Ford stuff on the D-30 for awhile. Ford parts are expensive and had to find

 

The springs are wider on the ‘77 but just to make a roller it can work. If you need it to steer that is another issue. Stock the 27 uses a single hole knuckle on passenger side. No provision for a drag link to hook to.

 

Just a parts donor no need to steer it. Is the '77's frame wider, I took the D27 out and bolted in the D30 from a '76. Had to do something to the shock mounts though. Funny thing though after I put in the D30 the Ross steering was still there. I hooked up the link to the p side knuckle, drove to Butler, Pa for Bantam Fest. Typical Ross steering 3" of play but it tracked straight.