The 24V lift pump is on the side of the engine block, there is no need to drain the tank. If I remember right, just remove the bolts holding the fuel filter canister in place and move it out of the way. After that it is pretty straight forward.
The heat and vibration from being on the side of the block is really hard on these pumps, plus it has to suck fuel up instead of pushing, which is also hard on a pump. Got tired of replacing them on my 01 24V so I got a kit to move it down to the frame and installed a shutoff between the tank and pump. Changing them was dead easy after that.
Remember to bump the starter several time before starting the engine. Each time you do it, the pump will run for several seconds to bring fuel up. Same procedure used after changing a fuel filter.