1. Place the new valve seal and seal retainer on the cap screw.
2. Attach a crescent to the flat part on the piston to prevent rotation, and
then screw the M6 x 12 mm cap screw into the bottom of the piston,
using the seal retainer and valve seal.
3. Insert a new gas return O-ring.
4. Insert the piston back into the solenoid body.
5. Insert the solenoid spring.
6. Insert a new solenoid top O-ring seal.
7. Place the solenoid top back on the solenoid body, making sure that the
locating dowel is engaged.
8. Screw in the six M6 cap screws.