Repair Guide; Precautions And Suggestions For Disassembly And Reassembly Of The Main Body - Hitachi H 70SD Technical Data And Service Manual

9. REPAIR GUIDE

9-1. Precautions and Suggestions for Disassembly and Reassembly of the Main Body

The [Bold] numbers in the descriptions below correspond to the item numbers in the Parts List and exploded
assembly diagram.
9-1-1. Disassembly
[NOTE] If it is difficult to loosen and remove the fixing bolts, use an appropriate heating device to heat them to
approximately 80˚C (176˚F).
Disassembly of the Armature Ass'y [88]
(1) Loosen the four Seal Lock Hex. Socket Hd. Bolts M4 x 12 [55], remove the Cap Covers [56], Cap Rubbers
[57] and Brush Caps [58], and take out the Carbon Brushes (Auto Stop Type) (1 Pair) [59]. At this time, be
very careful not to lose the disassembled parts.
(2) Loosen the four Nylock Hex. Socket Hd. Bolts M8 x 35 [21], and remove the Cylinder Case [18]. Next, after
loosening the Seal Lock Hex. Socket Hd. Bolt M8 x 16 [30], the Connecting Rod Ass'y [27] and Crank Washer
[29] can be disassembled. Leave the Striker [20] and Piston [25] as they are.
(3) Loosen the six Seal Lock Hex. Socket Hd. Bolts M6 x 45 [61], and disassemble the Gear Cover [32] and
Counter Gear [63]. Then, by inserting a flat-blade screwdriver or similar tool into one of the air vents of the
Inner Cover [36] and lifting it upwards, the Inner Cover [36], Armature Ass'y [88], Crank Shaft [41], and related
parts can be removed in a single body.
(4) As illustrated in Fig. 12, support the Inner Cover [36] with an appropriate tubular jig, and push down on the end
surface of the armature shaft with a hand press to separate the Armature Ass'y [88] from the Inner Cover [36].
Inner Cover [36]
Crank Shaft [41]
Disassembly of the Crank Shaft [41] section
First, remove the four Seal Lock Hex. Socket Hd. Bolts M5 x 16 [40] which fix the Bearing Cover [39]. Then,
as illustrated in Fig. 13, support the lower surface of the Inner Cover [36] with an appropriate tubular jig,
align an appropriate steel rod with the end surface of the Crank Shaft [41], and press down on the steel rod
with a hand press. The Ball Bearing 6205DDCMPS2L [38], Distance Ring (B) [35], Final Gear [34], two
Woodruff Keys 4 x 16 [42], and Crank Shaft [41] can then be disassembled from the Inner Cover [36].
Armature Ass'y [88]
Press the end surface of the armature shaft
with a hand press.
Fig. 12
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Tubular jig