Hitachi NT 65M2 Technical Data And Service Manual page 27

(b) Reassembly
Disassembly procedures should be followed in the reverse order. Note the following points.
Be extremely careful to prevent the entry of foreign particles into the control valve section.
Thoroughly apply grease to the O-Rings (I.D 1.8) [66] of the Plunger [67], the O-Rings (P-7) [62] and
(1AP-10) [64] of the Valve Piston [63].
First, align the roll pin groove of Valve Bushing (A) [68] with that of Valve Bushing (B) [60] and reassemble the
entire control valve unit as shown in Fig. 17. Then install the control valve unit so that the roll pin grooves in
the control valve unit will be aligned with the roll pin holes in the Body Ass'y [31]. First, insert the roll pin puller
(3 mm dia.) into the roll pin holes. Then, upon confirming that the puller passes through the hole, drive in the
Roll Pins D3 x 25 [53] and D3 x 32 [54].
If an attempt is made to drive the roll pin with force when the roll pin grooves in Valve Bushings (A) [68] and
(B) [60] are not aligned with the roll pin holes in the Body Ass'y [31], it will damage the periphery of Valve
Bushings (A) [68] and (B) [60], and prevent disassembly or reassembly.
Roll pin groove
After assembly, make sure that the Plunger [67] moves smoothly.
Roll pin groove in
Valve Bushing (A) [68]
Align
Roll pin groove in
Valve Bushing (B) [60]
Body Ass'y [31]
Roll pin holes
Roll pin groove
Roll Pin D3 x 32 [54]
Fig. 17
--- 24 ---
Roll Pin D3 x 25 [53]