Spa pump dissasembly

I was thinking there might be a more appropriate place for this but I haven't found one yet. Anyhow I recently aquired a hot tub with an Aqua-flo FloMaster XP 4.5 HP pump which came to me partially disasembled and missing a few bits. I had first thought I'd just buy a whole new pump but after realizing they're close to $400 I decided to take a shot at rebuilding this one. Before I break it, does anyone know how to remove the impeller? Does it just pull off the shaft, or is it threaded, and if so which direction is the thread? I know I need to get that off since the shaft seal is shot, the start and run caps are also missing but the windings pass the visual inspection and ohm meter check and the bearings feel ok which leads me to believe there's a good chance this thing will be fine with a bit of effort. Unfortunatly there doesn't seem to be much info on this particular pump online.