Hitachi DH 28PC Technical Data And Service Manual page 23

(b) Components in the Cylinder
Remove Striker [30] from inside of separated Cylinder [21]. Then insert a punch (or thin but rigid material)
into the inspection hole of Cylinder [21], hammer Stopper Ring [29] to move it from the groove in Cylinder
[21] in the arrow direction. Use a spring hook (J201, No.970977) to pull out Stopper Ring [29] from the
groove in the arrow direction. You can then remove Damper Holder (B) [28], Damper Holder (A) [26], O-
Ring (A) [27], Damper (B) [25], Damper Washer [24], and Second Hammer [23] from Cylinder [21].
Second Hammer [23]
Cylinder [21]
(c) Piston
Piston [36] remains in Crank Case [104]. Turn Crank Shaft [106], move Piston [36] toward the lower dead
end, then remove Connecting Rod [37] from Crank Shaft [106] and remove the piston assembly.
Crank Case [104]
Connecting Rod [37]
Piston [36]
Damper Washer [24]
Damper (B) [25]
Damper Holder (A) [26]
Crank Shaft [106]
-20-
Punch etc.
Stopper Ring [29]
Damper Holder (B) [28]
O-Ring (A) [27]
Crank Case [104]
Connecting Rod [37]
Spring hook
Crank Shaft [106]