Install the piston compression rings (8, Figure K-22) in the proper grooves on the piston
(6). Ensure the piston compression ring (8) gaps are staggered.
The piston compression ring gaps must be positioned such that no two
gaps are directly in line. Each gap should be staggered 90 degrees from
the adjacent gap.
Lubricate the piston compression rings (8) and piston (6) with MIL-L-2104 oil.
Installing the piston into the upper cylinder procedure presents several
opportunities for pinching body parts between moving parts. Use care
when lowering the piston into the upper cylinder.
Be careful not to damage any components while lowering the piston into
the upper cylinder. Do not rest any weight of the piston on the piston
Ensure the lifting pawl of the hammer trip assembly is disengaged,
hanging vertically, and not going to strike the piston nose and/or piston
compression rings when the piston is lowered into the upper cylinder.
Raise the piston (6) with a lifting device and sling attached to the piston lifting eyebolt (5)
so that the piston (6) hangs vertically in the sling. Lift the piston (6) into position directly
above the upper cylinder. Align and then carefully lower the piston (6) into the cylinder.
When all of the piston compression rings (8) are in the bore of the upper cylinder, lower
the piston (6) until fully seated on the impact block.
The top opening of the upper cylinder is tapered and will ease the entry of
the piston compression rings into the upper cylinder.
Lower the impact hammer back down onto blocks.
Loosen the lock nut (7) and remove the piston lifting eyebolt (5) from the top of the
Reinstall the four lower cylinder (impact block) lubrication fittings (4) on the lower
Install the catch ring cap on the upper cylinder (Page K-52).