Hitachi ZAXIS 120-6 class Operator's Manual page 371

 Metal Face Seal Fittings
Tight contact between metal flares on adaptor (7) and metal
connector (8) of hose (5) prevents pressure oil leakage. This
type of fitting is used on smaller diameter joints.
Precautions for Use
Connect or disconnect fittings with care not to damage seat
surfaces (9 and 10).
Tightening Torque:
Tighten fittings to the torque values shown below.
Wrench size (mm)
N·m
Torque
(kgf·m)
 Bent Tube
Tighten bent tube (11) mounted on the signal control valve
to the torque values shown below.
Wrench size (mm)
N·m
Tightening
torque
(kgf·m)
MAINTENANCE
17 19 22
25 30 40
(2.5) (3.0) (4.0)
17, 19
35
(3.5)
7
27
80
(8.0)
7-77
9 8 10 5
11
Signal Control Valve
M1U1-07-043
M202-07-051