Counterbalance Valve - Komatsu 830E Shop Manual

1.) If pressure is still below 3000 psi (20.7
MPa), continue increasing engine speed
in steps of 300 rpm, while in third stage
and observing pressure gauge.
2.) Continue monitoring pressure gauge until
engine high idle is attained.
c. If gauge indicates 3000 psi (20.7 MPa) while
at high idle, in POWER UP and in third
stage, counterbalance valve adjustment is
correct.
d. If gauge does not indicate 3000 psi (20.7
MPa) while in third stage and at high idle (or
a lesser rpm during step 1b, 1.) perform
"Counterbalance Valve Adjustment" proce-
dure.
L10016 05/03
Counterbalance Valve Adjustment
1. Loosen locknut on adjustment stem of counter-
balance valve (4, Figure 10-9) on manifold.
Turn adjustment stem fully clockwise to start
adjustment procedure so counterbalance valve
pressure is as low as possible.
Note: Turning adjustment stem in (clockwise)
decreases the pressure. Turning the stem out
(counterclockwise)
Complete valve adjustment range is 3 turns.
2. Start the engine and operate at high idle. Raise
the body while observing the pressure gauge.
3. Slowly adjust counterbalance valve to obtain
3000 psi (20.7 MPa) as the hoist cylinder 3rd
stage extends while in POWER UP. When
adjustment is complete, secure locknut on
adjustment stem.
4. Repeat
Check", Step 1 to verify proper adjustment.
5. Replace fitting in "PILOT VENT" port (8).
Remove pressure gauge.
6. Turn needle valve adjustment stem (9) out 3
turns and secure locknut.
Hydraulic Check-out Procedure
increases the
"Counterbalance Valve
pressure.
Pressure
L10-15