Hitachi DH 25PA Technical Data And Service Manual page 25

(3) Disassembly of the Cylinder
Remove the Cylinder Case [31] <31> from the Crank Case [46] <46> and disassemble the retainer section.
Remove the Pipe [25] <25>, then the Cylinder [2] <2> from the Cylinder Case [31] <31> by pulling it straight
toward the crank case side being careful not to scratch the Oil Seal [21] <21>.
Remove the Retaining Ring for D30 Shaft [22] <22> from the Cylinder [2] <2> and remove the Ball Bearing
6906 [23] <23> press-fitted onto the Cylinder [2] <2> with a hand press. The Retainer Sleeve [15] <15> and
the Cylinder [2] <2> can then be removed together. Remove the three Needle Pins [1] <1> from the perimeter
of the Cylinder [2] <2> and push the Retainer Sleeve [15] <15> to the outside from the inside of the Cylinder
[2] <2> with a hand press to remove the Retainer Sleeve [15] <15> and the Cylinder [2] <2>.
Remove the three Needles [16] <16> from the perimeter of the Retainer Sleeve [15] <15> and extract the O-
Ring [20] <20> from the inner part of the Retainer Sleeve [15] <15>. The Second Hammer [19] <19> can
then be removed from the Retainer Sleeve [15] <15>. For easy extraction of this O-Ring [20] <20>, fit a
Special Repair Tool J-201 Spring Hook H-75 [J-201] onto the outer circumference of the O-Ring [20] <20>,
and pull it out. As the O-Ring [20] <20> is employed to prevent idle striking, please advise customers to
replace it with new one whenever it is disassembled. Be careful not to lose the three Needle Pins [1] <1> and
the three Needles [16] <16>.
(4) Disassembly of the Gear and the Crank Shaft in the Crank Case
The slip clutch section can be removed from the Crank Case [46] <46> by tapping the end surface of the
Crank Case [46] <46> from the gear cover side with a plastic hammer.
Remove the Retaining Ring for D8 Shaft [45] <45> and the Ball Bearing [44] <44> from the slip clutch section.
Remove the Third Pinion [34] <34> press-fitted in the Bushing [43] <43> with a hand press.
Push the Clutch Shaft <54> in the Crank Shaft [47] <47> up to the end surface with a stick having a flat edge,
then pull out the First gear [53] <51>.
Be careful not to lose the Clutch Shaft, Clutch Spring <53> and two Steel Balls D4.76 <48> in the crank shaft
hole.
(5) Disassembly of the Change Lever Ass'y in the Gear Cover
Insert the blade of a flat-blade screwdriver between the Gear Cover <57> and the Stopper Spring <56> and
twist to remove the Stopper Spring <56>.
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