Repair Guide; Precautions And Suggestions For Disassembly And Reassembly Of The Main Body - Hitachi H 70SA 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 [56], remove the Cap Covers [57], Cap Rubbers
[58] and Brush Caps [59], and take out the Carbon Brushes [60]. At this time, be very careful not to lose the
disassembled parts.
(2) Loosen the four Nylock Hex. Socket Hd. Bolts M8 x 35 [22], and remove the Cylinder Case [19]. Next, after
loosening the Seal Lock Hex. Socket Hd. Bolt M8 x 16 [31], the Connecting Rod Ass'y [28] and Crank Washer
[30] can be disassembled. Leave the Striker [21] and Piston [26] as they are.
(3) Loosen the six Seal Lock Hex. Socket Hd. bolts M6 x 45 [62], and disassemble the Gear Cover [33] and
Counter Gear [64]. Then, by inserting a flat-blade screwdriver or similar tool into one of the air vents of the
Inner Cover [37] and lifting it upwards, the Inner Cover [37], Armature Ass'y [88], Crank Shaft [42], and related
parts can be removed in a single body.
(4) As illustrated in Fig. 6, support the Inner Cover [37] 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 [37].
Inner Cover [37]
Crank Shaft [42]
Disassembly of the Crank Shaft [42] section
First, remove the four Seal Lock Hex. Socket Hd. Bolts M5 x 16 [41] which fix the Bearing Cover [40]. Then,
as illustrated in Fig. 7, support the lower surface of the Inner Cover [37] with an appropriate tubular jig,
align an appropriate steel rod with the end surface of the Crank Shaft [42], and press down on the steel rod
with a hand press. The Ball Bearing 6205DDCM [39], Distance Ring (B) [36], Final Gear [35], two Woodruff
Keys 4 x 16 [43], and Crank Shaft [42] can then be disassembled from the Inner Cover [37].
Armature Ass'y [88]
Press the end surface of the armature shaft
with a hand press.
Fig. 6
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Tubular jig