Hitachi DH 24PF3 Technical Data And Service Manual page 34

(7) Mounting the piston
Mount the Piston [39] as shown in Fig. 25.
(8) Reassembly of the gear cover
After reassembly as shown in Fig. 26, ensure that the Change Lever [21] is adjusted to the "hammering only"
position. Engage the claws of the Clutch [51] and the Reciprocating Bearing [53] each other. Align the wing
portion of the Lock Plate [48] horizontally and reinstall the Gear Cover Ass'y [10] so that the wing portion of
the Lock Plate [48] is contained in the rail inside of the Gear Cover Ass'y [10]. When the Second Shaft [52]
contacts the Pinion Sleeve [47] inside the Gear Cover Ass'y [10], move the Change Lever [21] to the "rotation
and hammering" mode and rotate the Grip [3]. Then the Second Shaft [52] and the Pinion Sleeve [47] are
engaged and the end surface of the Gear Cover Ass'y [10] contacts that of the Housing [68]. At this time,
rotate the Grip [3] to check that the rotation of the Cylinder [24] is transmitted to the armature shaft.
Housing [68]
Engage the claws of the Clutch [51]
and the Reciprocating Bearing [53].
Inner Cover Ass'y [41]
First Gear [54]
End surface of the
Housing [68]
Position the wing portion of the
Lock Plate [48] horizontally.
Striker [37]
Reciprocating Bearing [53]
Fig. 25
Move the Piston [39] to the top dead center.
End surface of the Gear Cover Ass'y [10]
Rail in the Gear Cover Ass'y [10]
Spring (B) [22]
Move the Change Lever [21] to the
"hammering only" (
Fig. 26
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Piston [39]
Second Shaft [52]
Gear Cover Ass'y [10]
mark) position.