Hitachi ZX27U-2, Operator'S Manual, Page: 155 / 230

MAINTENANCE
7-35
•
Flat Face O-ring Seal Fitting (ORS Fitting)
O-ring (1) is used on the end face of adapter (2) to
prevent oil leakage between the joints.
Precautions for Application
1. Replace O-ring (1) with a new one when
re-assembling fittings.
2. Before tightening union nut (4), check that O-ring (1)
is correctly seated in O-ring groove (3). If union nut
(4) is tightened when O-ring is not correctly seated in
O-ring groove (3), damage to O-ring (1) and oil leak
from fittings may result.
3. Take care not to make dents on O-ring groove (3) of
adapter (2) and seal face (6) on the hose or valve
side (5) when re-assembling fittings. Failure to do so
may cause damage to O-ring (1) and oil leak from
fittings.
4. If oil leaks from a loose connection of union nut (4),
open the connection, replace O-ring (1), and check
that the O-ring is correctly seated in O-ring groove (3)
before re-tightening the connection.
Tightening Torque
Tighten adapter (2) and union nut (4) to the torque
values shown in the table below
±
10%
Width across flats (mm) 19 22 24 27
N
⋅
m 44 74 78 93
(kgf
⋅
m) (4.5) (7.5) (8.0) (9.5)
Fastening
torque
(lbf
⋅
ft) (32.5) (54) (57.5) (68.5)
M104-07-033
2 6 1 4 5
6
3