Mine having a gas 460 makes it easier...however, the big-truck (F-700, etc.) 370/429/460 water pump was something like $275. However, a pump for a md-70's 460 LTD police car is about $75. IT'S THE SAME BLEEPING PUMP! (IIRC, the pre-serpentine-belt big-block F-250/350 also uses it.)
For chassis stuff, many places, even pretty good ones, don't have buses in their system...I tell them it's an F-700 (and it really is...just happens to have a bus body on it
). That worked for brakes, hoses, and a master cylinder. My second alternator (charging the deep-cycle T-105's) is a regular GM 12SI (IIRC, the application is an early-80's police car), $45 at any part store. The alternator on my APU is something like Lapeer's bus has...a big-truck unit, probably rather pricey new (it came from a wreck).
As for the FJ-40 brakes, try asking for brake parts for a 1983 Land Cruiser.