On the Danco stem 3Z-6H/C does the plastic piece go on the rubber seat side of the spring or the other way around?

SOURCE: Where does the spring and rubber piece go when

http://kitchen-bath.hometownhardware.com/Faucet_parts-ssd70982-p9-l1-t1-Sv-dirasc-PP10.html

SOURCE: I bought the Danco replacement

Sometimes on the stems on the side the handle attaches is a nut that can be tightened. Inside this nut is a rubber or other type of seal. tightening this nut stops the water from coming out of the handle. If the nut has already been tightened then possibly need to replace this rubber seal.

SOURCE: Where does washer go for 12h-6h/c stem from Danco for faucet?

If it is red in color it is a #38 fiber washer and is the cap thread gasket.

SOURCE: How do the 3 pieces

first off, put the spring in the faucet big end down. then put the black rubber boot seal in next and push it into place. Then place the Stem in but be sure to line up the notches before you screw it all down. I hope the will help you....