. MAINTENANCE MAINTENANCE PROCEDURE MAINTENANCE MAINTENANCE PROCEDURE to the air red piston in the dust indicator its original 4 - 20 6. Replace O-ring (7) for cover (3) wit h new one. 7. Set the arrow mar k o n cove r ( 3) a t the top, install cleaner body, t hen secure with clip (2). 8. Replace the seal attached to cover (3) with new one. 9. he position (1) to