Leaking Jacuzzi Sand Filter Dial Valve

I have a Jacuzzi ST-24 sand trap pool filter . In the "Filter" position, the dial (multi-port) valve had a small leak into the waste line. I installed a ball valve on the waste line to buy me some time. Now the leak has gotten bad enough that water squirts under pressure through the waste discharge sight jar threads. I've read some previous posts about multi-port valve assemply replacement, valve re-building and O-ring replacement. Has anyone else gone through this process? Can the valve be rebuilt and/or O-ring replace on this Jacuzzi filter model? Does the whole valve assembly have to be replaced? (some valves have been discontinued) Thanks, BrianW