If it ends up the flush and reservoir screen cleaning doesn't do it, maybe you could pick up a used pump off a wrecked rig at a PickNPull or other wrecking yard in your area. For the belt tension, 1/2-3/4" of belt deflection is in the ballpark of proper belt tension. Meaning, if you grab the belt midway between the power steering pulley and fan pulley, you should be able to push the belt downward 1/2-3/4" and pull it up 1/2-3/4". If it's looser than that, you might get belt slippage. If it's tighter than that, it could put excessive strain on the pulley bearings.

To get to the power steering adjuster bolt, I found a much easier way to get on that bolt. In the passenger side wheel well, detach the forward rubber mud flap partially. With a long extension and 14mm socket, you can get a pretty straight shot to get onto that adjuster bolt. There are some hoses that get in the way a little but you can push them to the side enough to get your extension and socket in there. This is much easier than leaning over the engine and blindly getting onto the adjuster bolt with a ratcheting box end wrench or ratchet and socket.