Komatsu PC88MR-10 Shop Manual page 1198

50 Disassembly and assembly
Work equipment
1) Start the engine.
2) Set the arm cylinder to the most extended
position (maximum arm IN position), and
lower the work equipment to the ground.
a Anti-drop valve is installed to the arm
cylinder, its head side.
When the work equipment is lowered with
this posture, the oil in the head side of the
arm cylinder
remaining pressure is low.
Remaining oil amount on the head side is
low.
3) Turn the starting switch to OFF position.
4) Turn the starting switch to ON position.
5) Set the work equipment lock lever in FREE
position, and operate the R.H. and L.H. work
equipment control levers forward and
backward, and to the right and left.
a The work equipment can be operated
with the battery charged in the PPC
accumulator, but the battery charged in it
will be discharged after the work
equipment control lever is operated a
couple of times.
6) Start the engine, run it with the fuel control
dial in MIN (low idle) position for more than
10 seconds so that the PPC accumulator is
accumulated.
7) Repeat the steps 4. to 6. to release the
remaining pressure in the hydraulic cylinder
circuit.
8) Set the work equipment lock lever in LOCK
position.
9) Loosen the oil filler cap of the hydraulic tank
slowly, and bleed the air in the hydraulic tank.
a Leave the oil filler cap of the hydraulic
tank removed.
3. Anti-drop valve assembly
1) Place an oil container under the anti-drop
valve assembly to receive oil.
Place an oil mat as well in case the oil
leaks.
50-170
is drained, and the
2) Disconnect the hoses (1), (2), and (3).
The remaining pressure may damage
the O-ring, and the oil may be
splashed. Therefore, loosen the hose
while pressing the fitting and around it
with a cloth, etc.
3) Remove the clamp (4).
4) Disconnect the tubes (5).
5) Remove the U-bolt (7).
6) Disconnect the tubes (6).
7) Disconnect the tube (8).
Slowly loosen the fitting of the tube so
that the remaining pressure in the
circuit between the anti-drop valve and
the cylinder is released.
The remaining pressure may damage
the O-ring, and the oil may be
splashed. Therefore, loosen the tube
while pressing the fitting and around it
with a cloth, etc.
8) Remove the bolts (9) (4 pieces), and remove
the anti-drop valve assembly (10).
PC88MR-10