Hitachi DH 24PM Technical And Service Manual page 31

(5) Removal of the cylinder and the second gear (slip mechanism section)
Remove the Retaining Ring D30 [42] from the Cylinder [38] with a retaining ring puller. Then the Second Gear
[39], Spring (A) [40] and Washer (A) [41] can be removed from the Cylinder [38].
(6) Removal of the cylinder and the second hammer
Remove the Stopper Ring [50] from the inside diameter portion of the Cylinder [38]. Then the Second
Hammer [43], O-ring (1AP-20) [44], Hammer Holder [45], O-ring (B) [46], Damper (A) [47], O-ring (C) [48]
and Damper Holder [49] can be removed from the Cylinder [38]. As shown in Fig. 22, insert the no-hole side
of stopper ring jig (A) (J-341) into the Cylinder [38] until it contacts the end surface of the Damper Holder [49].
Hold the Cylinder [38] and the end surface of stopper ring jig (A) (J-341) with a vise, and compress Damper
(A) [47] (it moves a little when the Stopper Ring [50] is pressed with punch (C) (J-341)). Insert punch (C)
(J-341) into the 5-mm diameter hole (2 places) in the Cylinder [38] and tap the outside of the Stopper Ring
[50] until the Stopper Ring [50] cannot be seen from the 5-mm diameter hole (2 places) to remove the Stopper
Ring [50] from the groove of the inside diameter portion of the Cylinder [38]. Then remove the Cylinder [38]
from the vise and pull out the Stopper Ring [50] from the inside diameter portion of the Cylinder [38] with ring
puller jig (B) (J-341) being careful not to pop out the Stopper Ring [50]. At reassembly, replace the Stopper
Ring [50] with new one as the removed Stopper Ring [50] is deformed. To prevent idle hammering, also
replace O-ring (C) [48] with new one at reassembly.
Hammer Holder [45]
Second Hammer [43]
Vise
O-ring (B) [46]
Tap with a hammer.
O-ring (1AP-20) [44]
Damper (A) [47]
Punch (C) (J-341)
5-mm diameter hole (2 pcs.)
Damper Holder [49]
O-ring (C) [48]
Stopper Ring [50]
Stopper ring jig (A) (J-341)
Fig. 22
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Vise