Hitachi EX20UR-2 Manual page 16

GENERAL INFORMATION/Tightening
M202-07-051
Metal sealing faces (4) and (5) of adaptor (1) and hose
(2) fit together to seal pressure oil. Union joints are used
to join small-diameter lines.
(3) Take care not to damage 0-ring
groove (8) or sealing face (10).
Damage to 0-ring (6) will cause oil
leakage.
30°or 37°
IMPORTANT: (1) Do not over-tighten nut (3). Exces-
sive force will be applied to metal
sealing surfaces (4) and (5), possi-
bly cracking adaptor (1). Be sure
to tighten nut (3) to specifications.
Male Union Joint Female Union Joint
30°or 37
(2) Scratches or other damage to
sealing surfaces (4) or (5) will
cause oil leakage at the joint. Take
care not to damage them when
connecting /disconnecting.
0-ring Seal Joint
0-ring (6) seats against the end face of adaptor (7) to
seal pressure oil.
IMPORTANT: (1) Be sure to replace 0-ring (6) with
a
new one when reconnecting.
(2) Before tightening nut (9), confirm
that 0-ring (6) is seated correctly
in 0-ring groove (8). Tightening
nut (9) with 0-ring (6) displaced
will damage 0-ring (6), resulting in
oil leakage.
(4) If loose nut (9) is found to be
loose, causing oil leakage, do not
tighten it to stop leakage. Instead,
replace 0-ring (6) with a new one,
then tighten nut (9) after confirm-
ing that 0-ring (6) is securely seat-
ed in place.
w105-01-01-017
Wrench Size
RIM
Tightening Torque
N•m ( kgf.m, lbf•ft )
19
29 ( 3.0, 22 )
22
39 ( 4.0, 29 )
27 93 ( 9.5, 69 )
32
137 ( 14, 101 )
36 175 ( 18, 130 )
41 205 ( 21, 152 )
50
255 ( 26, 188 )
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0 (ID
M104-07-033
Wrench Size
Mtn
Tightening Torque
N-rn ( kgf-m, lbf-ft )
27 93 ( 9.5, 69 )
32 137 ( 14, 101 )
36 175 ( 18, 130 )
41, 46
205 ( 21,152 )
PIPING JOINT
Pipe Thread Connection I Union Joint Tightening
Torque Specifications
Union Joint
0 0
W01-02-07