Hayward SP-733 Dial-A-Flo advice... no parts available, what to replace with?

[Engident]

Hi
I have a very old Hayward SP-733 (SP0733) Dial-A-Flo 3-way multiport valve. My pump (3 years old) can't maintain siphon once the pool drains down more than a foot. I can recirculate off the bottom, skimmers, or both if the pool is full, but when I try to drain down the pool a little with the valve switched to the bottom drain it loses siphon once the water level gets a few inches below the skimmer inlets. The valve is from the 1990s, I'm almost certain it is original, no idea if it's ever been rebuilt. Problem is, parts are no longer made for it. If I've missed something out of the many sites I've combed through, I'd love to know. So, my questions are:
1) if parts exist for this valve somewhere, where?
2) Exactly what make / model valve would you recommend to replace it?
Thanks!
Dave

[Denniswiseman]

Why would you want to drain down below the skimmer level?
Some main drains are connected to the skimmer so once you go below it it won't work
I doubt that there is anything wrong with it as it's only a diverter valve which is easily replaced