I have an Isuzu factory service manual for a 2001 Rodeo,which of course has the same engine as your vehicle.
The removal procedure for the PS pump in this manual does not require removal of the pulley. Looking at the
illustration in the manual, it seems to depict 2 bolts holding the pump to the bracket, and 2 bolts holding the
bracket to the engine. The removal of the AC pump does not require removal of the pulley either. The illustration
for the AC pump shows 2 bolts holding the bracket to the engine and 2 bolts holding the pump to the bracket.
http://www.myisuzuparts.com/1998/781/4/ ... parts.html
shows the same illustration for the PS pump as the FSM
These are the bolt sizes shown in the illustration
10 X 100 7A
8 X 25 7B
8 X 100 29A
8 X 40 29B
Also note that on the illustration there is an earlier version pump depicted that shows the pulley is bolted on.
01 Rodeo Sport Ironman 4X4 V6 134K miles
01 Rodeo Sport 4X4 V6 48K miles
02 Rodeo Sport 4X4 V6 65K miles