i had the same kind of problem here in that a reg i got free was fully incrusted in soda. the insides are simply a plate moved by the adjustment screw, a large washer/flapper attached to the underside of the plate and a spring to provide tension on the back of the plate. most rebuild kits are manufacturer specific and have those 3 pieces included.
i never did rebuild it since i couldn't find a reasonable price for one and i then found another secondary body for cheap($5us iirc) at scientific surplus.
primary1 :UTOPIA BABY(still searching for it)
secondary:middling bastard ipa
kegged:simcoe blonde, crystal pale ale, yellow jacket golden ale, lemon shandy blonde
DRINKIN DAWG BREWERY
LET'S GO RED WINGS
join michigan mashers here
grains in pounds(G) X 36(average points per gallon of grains) / batch size in gallons(g) = maximum efficiency(ME)
OG / ME = brewhouse efficiency