Hitachi H 70SA Technical Data And Service Manual page 18

9-1-2. Reassembly
Reassembly can be accomplished by following the disassembly procedures in reverse. However, special
attention should be given to the following items.
Reassembly of the Crank Shaft [42] section
Press-fit the Ball Bearing 6205DDCM [39] into the Inner Cover [37], and fasten the Bearing Cover [40] onto
the Inner Cover [37] with the four Seal Lock Hex. Socket Hd. Bolts M5 x 16 [41]. Support the inner race of the
Ball Bearing 6205DDCM [39] with an appropriate jig, and press-fit the Crank Shaft [42] into the Ball Bearing.
Next, insert Distance Ring (B) [36] and two Woodruff Keys 4 x 16 [43] into the Crank Shaft [42], and press-fit
the Final Gear [35] and Ball Bearing 6302VVCM [34] with a hand press.
Reassembly of the Armature Ass'y [88]
Press-fit the Ball Bearing 6203DDCM [67] into the Inner Cover [37], and fasten Bearing Cover (A) [66] onto
the Inner Cover with the three Seal Lock Hex. Socket Hd. Bolts M5 x 16 [41].
Reassembly of the Striker [21] (Two possible methods)
(1) After the Connecting Rod Ass'y [28] has been
assembled into the Housing Ass'y [104], mount the
Piston [26] and press it into the Striker [21].
Connecting Rod Ass'y [28]
Piston [26]
Respiratory holes
Either of the two methods described above requires a pressing force of more than 30 kg. When a "hissing"
sound is heard, the Piston [26] is properly inserted in the Striker [21]. (The "hissing" is the sound of the
compressed air escaping from the Striker [21] when the Piston [26] reaches the respiratory chambers within
the Striker [21].)
(2) Mount the Piston [26] onto the Connecting Rod
Housing Ass'y [104]
Striker [21]
Piston [26]
Respiratory holes
Fig. 10
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Ass'y [28], and push down on the Connecting
Rod Ass'y to press the Piston into the Striker [21].
Connecting Rod Ass'y [28]
Striker [21]