You must not have read far enough or fully understood the link 4crawler gave you. This one...

http://www.4x4wire.com/toyota/maintenance/front_end/

Read the "BEGIN DISASSEMBLY" link. This shows you how to remove the rotor and hub assembly off the knuckle.

Next read "REMOVE AND REPLACE BRAKE ROTORS" link. In this page is says "If your truck is IFS or an early solid axle (1979-1980) removing and replacing rotors is an easy task. Remove the 6-14mm bolts from the back side of the wheel hub, and pull the rotor off of the wheel hub." Your truck is an IFS, so follow these directions.

One tip to make separating the wheel hub from the rotor is to use a pickle fork inbetween the two. They are pretty well stuck together, and this is the only way I could get them apart.

Also, in place of a 54mm socket, you can use a 2 1/8" socket from Sears. Otherwise you will have to order a 54mm from places like marlincrawler.com or trail-gear.com