
96 31200243
Operation Section
3. Locate control valve (14). Refer to Illustration 155.
4. Measure the distance from the head of adjustment
screw (16) to the top of locknut (15). Completely
remove locknut (15). Turn the screw clockwise by
hand until the screw is tight. Use an allen wrench to
turn the adjustment screw clockwise in order to
lower the boom. Allow the boom to fully lower.
Note: If necessary, turn adjustment screw (16)
counterclockwise in order to stop the boom from lowering.
5. When the boom has fully lowered, turn adjustment
screw (16) in a counterclockwise direction until the
adjustment screw is returned to the original
position.
6. Tighten locknut (15).
Note: Do not start the engine until you have reset
adjustment screws (16) and (20).
7. Start the engine. Raise and lower the boom.
Extend and retract the boom approximately 300
mm (12 inch).
8. Position the boom to the fully retracted position.
Position the boom to the fully lowered position.
9. Remove the hydraulic tank filler cap. Add the 12 L
(3.17 US gal) of oil that was removed from the tank
in Step 3 of "Procedure for Draining Hydraulic Tank".
10. Check the oil level in the hydraulic tank. If
necessary, top up the hydraulic oil to the required
level. Install the hydraulic tank filler cap. Clean up
any oil that may have been spilled. Refer to
Operation and Maintenance Manual, "Lubricant
Viscosities" and Operation and Maintenance
Manual, "Capacities (Refill)" for further information.
11. Install the access cover on the chassis.
Resetting the Load Control System
Resetting the Load Control Valves
1. Reset adjustment screw (12) to the measurement
that was recorded in Step 2 of "Procedure for
Retracting the Boom". Refer to Illustration 153.
2. Reset adjustment screw (20) to the measurement
that was recorded in Step 2 of "Procedure for
Lowering the Boom". Refer to Illustration 156.
3. Secure adjustment screw (12) with locknut (13).
Also, secure adjustment screw (20) with locknut
(21).
4. Repair the machine before you return the machine
to service.
Purging Air from the System
Air may have entered the hydraulic system. Ensure that
the air is purged from the hydraulic system before the
machine is returned to service.
Note: Purging air from the system should be
performed on an unloaded boom.
1. Fully raise the boom and fully lower the boom.
2. Repeat this procedure three times in order to purge
the air from the hydraulic system.
3. Fully extend the boom and fully retract the boom.
The boom operation should be smooth.
4. If necessary, repeat this procedure in order to purge
the air from the hydraulic system.
Verifying the Correct Setting of the Load Control
Valves
1. Install a work tool onto the quick coupler. Raise the
boom until the work tool is clear of the ground.
Extend the boom by approximately 300 mm (12
inch).
2. Look at the boom extension reference scale and the
boom angle reference scale and note the readings.
Refer to the load chart and use these two values in
order to determine the maximum weight that can
be lifted with the boom in this position.
3. Pick up the maximum load that was determined in
Step 2. Refer to the procedure for load handling
and stacking in Operation and Maintenance
Manual, "Operation Information".
4. Extend the boom approximately 300 mm (12 inch)
and fully raise the boom.
5. Stop the engine.
6. Turn locknut (15) and locknut (17) on control valve
(14) for one turn in a counterclockwise direction.
Turn adjustment screw (16) and adjustment screw
(18) in a counterclockwise direction for four full
turns. Refer to Illustration 155.
7. Check the position of the boom after 10 minutes.
The cylinder for the boom retract and the cylinder
for the boom raise should not have drifted. If either
cylinder has drifted, consult your Caterpillar dealer.
Do not operate the machine until any necessary
repairs are completed or until any necessary
adjustments are completed.
8. Turn adjustment screw (16) and adjustment screw
(18) in a clockwise direction. Tighten the screws.
9. Tighten locknut (15) and locknut (17).