Hitachi NR 65AK Service Manual page 31

(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-Ring (I.D 1.8) [48] on Plunger (A) [47], O-Rings (I.D 11) [43], (S-18) [41]
and (S-4) [45] on Valve Piston (B) [44], and the shaft of Plunger (A) [47] as shown in Fig. 26.
As shown in Fig. 26, install Valve Bushing (A) [49] so that the roll pin groove in Valve Bushing (A) [49] will be
aligned with the roll pin hole in the Body Ass'y [18]. First, insert a roll pin puller (3 mm (0.118 ") dia.) into the
roll pin hole. Then, upon confirming that the puller passes through the hole, drive in the Roll Pin D3 x 28 [38].
If an attempt is made to drive the roll pin with force when the roll pin groove in Valve Bushing (A) [49] is not
aligned with the roll pin hole in the Body Ass'y [18], it will damage the periphery of Valve Bushing (A) [49] and
prevent disassembly or reassembly.
Body Ass'y [18]
Roll pin
groove
After assembling, check that Plunger (A) [47] moves smoothly.
Roll pin hole
Roll Pin D3 x 28 [38]
Valve Bushing (A) [49]
Apply grease to the stem.
Valve Bushing (A) [49]
Fig. 26
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Coat the O-ring
groove's shaft
with grease.
Plunger (A) [47]