Komatsu PC88MR-10 Shop Manual page 410

30 Testing and adjusting
Hydraulic system
Adjusting
(PC88MR-0000-270-K-00-A)
a If travel deviation occurs, you can correct it by
draining a part of the discharge of the pump of
larger discharge into the tank circuit by using the
adjustment plug. (Take care that the travel
speed, work equipment speed in combined
operations, and relief pressure may decrease
since the pump discharge decreases if you use
this method.)
a The following is the correction method
applicable when the machine deviates in the
same direction during both forward and reverse
travels (If the deviation direction in forward
direction and reverse direction differs, the cause
of failure may be something other than the
hydraulic pump. In this case, perform
troubleshooting).
a Only when it is 200mm or less, travel deviation
can be corrected with this method.
If the adjustment plug is loosened more than
the adjustment limit, high-pressure oil may
spout out. Work with extreme care.
Lower the work equipment to the ground and
stop the engine. Operate the control levers
several times to release the remaining
pressure in the piping, and then loosen the
oil filler cap of the hydraulic tank slowly to
release the internal pressure.
1. Check the travel deviation direction and the
positions of adjustment plugs (1) and (2).
(1): Right deviation adjustment plug (pump
P )
1
(2): Left deviation adjustment plug (pump P
a Adjust by loosening only either plug. Do not
loosen the opposite one.
2. Loosen lock nut (3) while fixing plug (1) or (2)
with a hexagonal wrench (width across flats: 4
mm).
a Securely insert the hexagonal wrench.
30-60
a If the lock nut is sealed with a vinyl seal,
remove the tape to work.
a Before loosening the lock nut, make a
matchmark between the lock nut and pump
case.
Loosening angle of lock nut: Approximately
90 to 180 deg.
3. Loosen plug (1) or (2), and adjust the travel
deviation.
Quantity of adjustment per turn of plug:
150mm (reference)
a The plug is fully tightened when the machine
is shipped. Adjust by the loosening angle
from that condition.
a If the plug is dragged when the lock nut is
loosened, tighten the plug fully once, and
then adjust it.
a The plug may be loosened up to 2 turns (720
deg.) from the fully tightened condition.
)
2
4. Tighten lock nut (3) while fixing plug (1) or (2)
with an hexagonal wrench.
Lock nut:
11.8 to 14.7 Nm {1.2 to 1.5 kgm}
a After tightening the lock nut, seal the hole of
it with a vinyl seal.
5. After the adjustment, check the travel deviation
again according to the above test procedure.
a Adjustment limit (2 turns/ 720 deg. or less) by
adjustment plug must not be exceeded.
PC88MR-10