My wagon acts like it doesn't have power steering. Where do I start looking for the problem? The only thing I knew to do was check the pump fluid.

After you replace the power steering fluid jack up the front end and spin the wheel back and forth to check the u-joints on the steering linkage, these joints can tighten up causing hard steering. If they are tight you could try heat and lubricant to free them up.

My Friend,
The first thing you definitely want to do is flush all the old power steering fluid out of the rack. This is often overlooked as a part of regular maintainence. Cleaner is much "more better"!!! As the other posts suggest, check the belt. Also, inspect the rack itself...look for cracked boots...loose tie rod ends...or any other irregularity. Do you own a Bently Service Manual? The very last thing I'd do is replace the rack. Only after all other variables have been considered first. Peace

Make sure the drive belt is snug.

Loose power steering belt?