Hitachi EX1900-5 Operator's Manual page 180

7. When connecting hydraulic hoses and pipes, take
special care to keep seal surfaces free from dirt and
to avoid damaging them. Keep these precautions in
mind:
a. Wash hoses, pipes, and the tank interior with a
washing liquid and thoroughly wipe it out before
reconnecting them.
b. Only use O-rings that are free of damage or
defects. Be careful not to damage them during
reassembly.
c. Do not allow high pressure hoses to twist when
connecting them. The life of twisted hoses will be
shortened considerably.
d. When connecting screw type joints, apply seal
tape to the threads of male screw. Be sure to
leave a couple of threads at the male screw top
unwrapped, as shown. Do not overwrap. Apply
seal tape around threads as shown, so that the
tape does not loosen when the female screw is
tightened.
e. Carefully tighten low pressure hose clamps to
following torque specifications. Do not
overtighten.
T Bolt Clamp:
4.4 N m (0.45 kgf m, 3.3 lbf ft)
Jubilee Clamp:
5.9 to 6.9 N m
(0.6 to 0.7 kgf m, 4.3 to 5.1 lbf ft)
f. Carefully tighten nut for bandy pipe to following
torque specifications on the right side. Do not
overtighten.
8. When adding hydraulic oil, always use the same
brand of oil; do not mix brands of oil. As the machine
is filled with Super EX 46HN when it is shipped from
the factory, use it as a general rule. When selecting to
use another brand of oil listed in the table "Brand
Names of Recommended Hydraulic Oil", be sure to
completely replace the oil in the system.
9. Do not use hydraulic oils other than those listed in the
table "Brand Names of Recommended Hydraulic Oil".
10. Only 50 to 60% of the total hydraulic circuit oil on a
large size excavator can be replaced at a time.
Accordingly, conduct minimum flushing twice.
11. If any other hydraulic oil (having a different
replacement interval) is unavoidably used, replace
the oil in accordance with the individual replacement
interval standard.
12. In case the machine is used for dredging operations,
replace the hydraulic oil at a 2000 hour interval
regardless of the oil brand used.
13. Never run the engine without oil in the hy-draulic oil
tank.
MAINTENANCE
Width across flat (B) (mm)
Fastening Torque
7-48
A couple of threads left unwrapped
Direction of
Tape Winding
T Bolt Clamp
Pipe Dia. (A)
N m
kgf m
lbf ft
M114-07-041
Jubilee Clamp
M114-07-042
M114-07-043
φ8 φ10
17 19
34 40
3.5 5
25.5 36
M117-07-149