Tips on how to remove this stubborn Balance Spool?

[Tdkdpt]

My old American Standard valve is not allowing us to get hot water. I’ve tried taking out the check stops and flushing the valve. I’ve replaced the cartridge. I have adjusted the scald limit. The only thing I can think of from troubleshooting is the valve and this balance spool but I can’t remove it!

 

[Breplum]

A suitably sized screwdriver is what we use.
Alt. is large Crescent (adjustable) wrench facing straight in if not normal if you have the room.

 

[Sponsor]

 

[hj]

A crescent wrench and a hammer.