There is an adjusting nut behind the power steering pump almost below it is more accurate.
- Loosen it up and the bolt holding the power steering pump on the block.
- The power steering pump should be able to move at a particular angle.
- Use a pry bar to pry it so the belt is tight, (but not excessively tight)
- At the same time you are putting pressure on the pump, re-tighten the adjusting nut.
-Tight the bolt attaching it to the block and your done.
Make sure there are no knicks, chunks, cracks on the belt. If there are, replace it.
Also that squeak is probably the pump and not the belt, btw.