NOTE: This information is also applicable to Land Cruiser owners who have swapped in mini-truck knuckles so they can have disk brakes.
First of all you need to pick up a set of 81+ Toyota Land Cruiser FJ40 brake rotors. They're vented and have the same dimensions as the solid axle rotors except for the fact that they're vented. (Jack says he paid $59.99 each for mine at Advanced Auto, but mine were $107.00)
The next thing you need to get is a set of 86+ Toyota 4x4 IFS calipers. (I had a set left from my IFS to solid axle conversion so I didn't have to buy these.) IFS trucks are abundant in junk yards so brake calipers should be easy to come by. Or you could trade your solid axle calipers in on a set of re-built IFS calipers, the guy at the parts counter would never know the difference ... the only real difference is that the IFS calipers are wider to accommodate the vented rotors, the bolt hole widths that mount the calipers are identical.
Once you've got all these parts accumulated you need to disassemble the front axle down to the spindle. Remove the bearings from the axle hub, (or if you've got some way to keep dirt out of the bearings just leave the inner bearing, seal and all in place). I replaced my front wheel bearings while I was there so I stripped it down completely, repainted it and put new bearings in. But before I put the new bearings in I got the violent part of this swap out of the way: removing the wheel studs from the axle hub !
Removing the wheel studs from the axle hub is no big task, it just requires a lot of brute force. The wheel studs are driven through undersized holes in the rotor and then through a hole in the axle hub that's a bit smaller then the o.d. of the wheel stud. I had some old lug nuts lying around, so to keep from buggering up the wheel studs I screwed a lug on to each wheel stud, placed the rotor on a piece of wood on my workbench, I used a piece of 3/4" x3/4" x ~8" steel stock as a punch to drive the wheel studs out. The driving out of the wheel studs took quite a good bit of effort ! (An air hammer makes quick work of this chore.)
Once I had all the studs out I removed the two bolts holding the rotor to the axle hub and then pulled the rotor loose from the axle hub. Since I was replacing the bearings, I drove the races out and then sanded and painted the axle hub. Once several coats of paint were dry I drove new inner and outer races into the axle hub and reassembled the axle hub to the rotor. It was just as much work putting the studs back in as it was getting them out ! I used a little 3 lb. sledge and I still had to hit each stud quite a few times. I then replaced the two bolts that screw into the axle hub through the rotor.
Then I packed my new Federal-Mogul front wheel bearings and drove in a new grease seal, not forgetting to coat the lip of the new seal with some wheel bearing grease. I then put the axle hub back on the spindle and reassembled all that, not forgetting to put anti-seize on the cone washers to continue to make their removal easy. Once I had all that reassembled and the proper pre-load put on the front wheel bearings. Next I hosed the rotor down with an ozone depleting blast of brake cleaner and bolted up the IFS calipers, with a set of solid-axle brake pads out of my solid-axle calipers. (The IFS and solid-axle brake pads are identical, I used the solid axle set because they still had about 2/3 left and the IFS set that came out of those calipers only had about 1/2 left). Then just screw the brake line back into the caliper, bleed the brake system and you're off and stopping better than ever.