Hitachi H 90SE Technical Data And Service Manual page 18

Disassembly of the Crank Shaft [84] section
Remove the four Seal Lock Hex. Socket Hd. Bolts M8 x 18 [81]. As illustrated in Fig. 14, support the lower
surface of the Inner Cover [76] with an appropriate tubular jig (100 mm inner dia.), apply an appropriate steel
rod (maximum diameter of 19 mm) to the end surface of the Crank Shaft [84], and push it downward with an
arbor press. The Ball Bearing 6204VVCM [62], Distance Ring (A) [63], Distance Ring (B) [65], Distance Ring
(C) [77], Final Gear [64], Feather Keys 4 x 4 x 10 [70], Bearing Boss [80], Ball Bearing 6305VVCM [78] and
Crank Shaft [84] can then be removed from the Inner Cover [76].
Then, remove the three Seal Lock Hex. Socket Hd. Bolts M5 x 12 [71], and take off Bearing Cover (A) [72]
and the Ball Bearing 6203DDCM [73].
Distance Ring (A) [63]
Inner Cover [76]
Disassembly of the Front Cover [7] section
Secure the Cylinder Case [15] in a vise, and heat the Cylinder Case mounting portion of the Front Cover [7] to
a temperature of approx. 80 ˚C (176 ˚F) with an appropriate heating device. Then, remove the six Nylock High
Tension Bolts M12 x 40 [4]. The Front Cover [7] together with the Second Hammer [10] and the Hammer
Holder [13] can then be removed from the Cylinder Case [15] in a single body. The Damper [14] can then be
taken out.
Removal of O-Ring (A) [12]
As O-Ring (A) [12] is installed in the inner portion of the Hammer Holder [13], it may be difficult to remove. As
illustrated in Fig. 15, pry O-Ring (A) upward gently with a small flat-blade screwdriver, being very careful not to
damage the surface of the O-Ring.
Hammer Holder [13]
Push
Crank Shaft [84]
Fig. 14
Fig. 15
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Final Gear [64]
Tubular jig
Flat-blade screwdriver
O-Ring (A) [12]