Leaking PacFab Valve

I have a PacFac (now Pentair) 50118300 valve on my sand filter.

During the extremely cold weather, I had to backflush my filter, and it is now leaking from the top valve assembly and dripping down the outside of the sand filter housing. I check the sprider gasket and it looks good, so I suspect the o-rings on the shaft of the spider gasket assembly.

I'd like to rebuild the top valve assembly, but I'm not sure how to approach this project give it's spring loaded. Should I remover the pin while the lid is still installed on the valve?

Thanks for the help.

I had to replace the "O" ring on the valve stem on my PacFab DE filter, suspect the valve is similar. I removed the top half and used a vise to slightly compress the spring so I could remove the pin and then remove the handle so the stem can be removed to replace the "O" ring. Be careful when compressing the spring assembly to not scar the face of the multi port valve assembly.
Also when reassembling make sure the handle is positioned properly as on my valve you can put it back together 180 degrees off, guess how I know?
Lube the new "O" ring.

Good Luck,
David