Hitachi DH 38MS Technical Data And Service Manual page 16

(d) Slip Clutch
Refer to the Technical Data and Service Manual for the Model DH 40MR (List No. E467) because the slip
clutch mechanism is the same as that of the Model DH 40MR.
Perform reassembly by reversing the order of the disassembly procedure. However, special attention
should be given to the following items.
1. Reassembly of the hammering mechanism
(a) First Gear [78] and Crank Shaft [73]
Press-fit Oil Seal (B) [77] into the Crank
Case [70] and mount the O-ring [76]. Then
press-fit the Ball Bearing 6203DDCMPS2L
[75]. Use a retaining ring puller to mount the
Retaining Ring for the D40 Shaft [74].
Press-fit the Crank Shaft [73] into Ball
Bearing 6203DDCMPS2L [75]. Put the
Feather Key 3 x 3 x 8 [51] into the groove of
the Crank Shaft [73] and then press-fit the
First Gear [78] with a suitable jig, while
holding the flat portion of the Crank Shaft
[73] with a steel bar. Before press-fitting,
make sure that the Feather Key 3 x 3 x 8
[51] fits into the key groove of the First Gear
[78] (Fig. 4).
(b) Piston [30]
Insert the Connecting Rod [31] into the Piston [30] and then insert the Piston Pin [29] into the 8-mm dia.
hole (on the marked side) of the Piston [30]. (Be careful not to protrude the Piston Pin [29] from the outer
diameter of the Piston [30].) Mount the O-ring [28] to the Piston [30] to complete the piston ass'y. Move the
crank pin of the Crank Shaft [73] to the bottom dead center, and then mount the piston ass'y to the Crank
Shaft [73] from the Cylinder Case [7] side of the Crank Case [70]. Use a retaining ring puller to mount the
Retaining Ring for the D10 Shaft [72] (Fig. 5).
Fig. 5
Mark
Piston Pin [29]
O-Ring [28]
Piston Ass'y
Reassembly
Piston[30]
Connecting Rod [31]
Crank Case [70]
BB.6203DDCMPS2L [75]
Fig. 4
First Gear [78]
Oil seal (B) [77]
O-ring [76]
Crank Shaft [73]
Retaining Ring for D10 Shaft [72]
-13-
3 x 3 x 8 Key [51]
Support
Steel Bar
Retaining Ring for D40 Hole
Crank Shaft [73]