Hitachi Zaxis 33U-5A, Operator'S Manual

Page: 216 / 340

MAINTENANCE
7-48
2 1 4 5
3 6
Service Recommendations for Hydraulic Fittings
Two hydraulic fitting designs are used on this machine.

Flat Face O-ring Seal Fitting (ORS Fitting)
O-ring (1) is used on the sealing surfaces of adapter (2) to
prevent oil leakage.
Precautions for Use
1. Replace O-ring (1) with a new one when assembling
fittings.
2. Check that O-ring (1) is properly fitted in O-ring groove
(3). Tighten union (4).
Tightening union (4) with O-ring (1) out of the groove
may damage O-ring (1) and cause oil leak.
3. When assembling fittings, take care not to make a dent
on O-ring groove (3) of adaptor (2) and sealing surface
(6) on hose (5) or valve side. Failure to do so may result in
damage to O-ring (1) leading to oil leak.
4. If oil leaks from a loose connection of union (4), do not
tighten fitting (2). Open the connection, replace O-ring
(1) with a new one and check for correct O-ring position
before tightening the connection.
Tightening Torque:
Tighten fittings to the torque values shown below.
±10 %
Wrench size (mm) 19 22 24 27 36 41
Tightening
Torque:
N·m 30 70 80 95 180 210
(kgf∙m) (3.0) (7.0) (8.0) (9.5) (18) (21)
(lbf·ft) (22) (52) (59) (70) (130) (152)
M104-07-033