Based on what Deo shared on the 81 FJ40 disc brake axle we got, we lucked out getting the beefier parts (knuckles, steering arms, 60 series rotors).
Based on what
@Poser had to say in the steering knuckle 101 FAQ (excerpt below, full link here
Steering Knuckle 101....(FAQ)) we will swap the knuckle end bits to Old Landy’s existing galvanized axle housings to get it converted to disc brakes in the front. This keeps most of Old Landy’ 1978 original stuff intact.
“
1979-1990 40/55/60/62/70 series steering knuckles/spindles/calipers all interchange.
From
08/75-07/80 the rotors and wheel bearing hubs used six 10mm bolts to retain the rotor to the wheel bearing hub, opposed to the
08/80-1990 rotors being retained to the wheel bearing hub by the six wheel studs in addition to two 10mm bolts.
Calipers all interchange through this era of the Land Cruiser;
08/75-1990
40/55 steering arms, while they have the same 'large' pattern where they attach to the steering knuckle, use a smaller tie rod end, so consequently, the hole/taper is smaller on these arms. The 60/62/70 used the same arms with the larger hole for the tie rod ends.”