Hitachi DH 28PC Technical Data And Service Manual page 25

Perform reassembly by reversing the order of the disassembly procedure. However, special attention
should be given to the following items.
1. Reassembly of the hammering mechanism
(a) First Gear and Crank Shaft
Press-fit Oil Seal (B) [84] into Crank Case [104], mount O-Ring (S-32) [109], fit Ball Bearing
6002DDCMPS2L [108], and mount Retaining Ring for D32 Hole [110] by using the stopper ring puller. Use
the hand press to press-fit Crank Shaft [106] into Ball Bearing 6002DDCMPS2L [108]. Then fit Feather Key
3 x 3 x 8 [107] into the groove of Crank Shaft [106], support the flat face of Crank Shaft [106] on an
adequate steel rod, and then use an adequate tool to press-fit First Gear [111]. Confirm that Feather Key 3
x 3 x 8 [107] is firmly seated in the key groove of First Gear [111] before press-fitting. Be sure to support
the flat surface of Crank Shaft [106] with the steel rod since the abutting surface has steps.
Crank Case [104]
(b) Piston
Remount O-Ring (I.D 19.2) [31] on Piston [36], apply a small amount of power tool grease No.29 to Piston
Pin [35], and then insert Piston Pin [35] into Piston [36] and Connecting Rod [37]. Then move Crank Shaft
[106] toward the lower dead end, insert the piston assembly from the cylinder case side of Crank Case
[104], and mount it on Crank Shaft [106].
Crank Case [104]
Piston [36]
O-ring [62]
Reassembly
Crank Shaft [106]
Connecting Rod [37]
Piston Pin [35]
Hand press
Crank Case [104]
-22-
Suitable steel bar
Crank Shaft [106]
Oil Seal (B) [84]
O-Ring (S-32) [109]
Ball Bearing
6002DDCMPS2L [108]
Retaining Ring for D32 Hole [110]
First Gear [111]
Feather Key 3 x 3 x 8 [107]
Suitable tool
Crank Shaft [106]
Connecting Rod [37]