Note: This procedure is used for machines that are equipped with the "heavy lift option". If the machine is not equipped with the "heavy lift option", refer to Testing and Adjusting, "Relief Valve (Signal Limiter)".
Note: For machines that are equipped with heavy lift, always perform the following tests in the correct sequence. Failure to perform the procedures in the correct order will result in an improperly adjusted valve.
- Adjustment for heavy lift pressure
- Adjustment for normal operating pressure with heavy lift off
| Required Tools | ||
|---|---|---|
| Part Number | Part Description | Qty |
| 8T-0861 | Pressure Gauge | 1 |
| 6V-3989 | Unvalved Nipple | 1 |
| 6V-4143 | Coupler Assembly | 2 |
| 6V-3014 | Hose | 1 |
| 123-6471 (1) (2) | Diagnostic Tool Group | 1 |
| 126-7877 | M300 to PC RS-232 Cable | 1 |
| ( 1 ) | 123-6472 Portable Diagnostic Tool (PDT) is included in 123-6471 Diagnostic Tool Group . |
| ( 2 ) | A laptop computer may be used as a substitute. The laptop computer must use M300 Technician software. |
Heavy Lift Circuit (Engine Speed)
Test (M300 Technician)
- Prior to any adjustment, refer to the "Preparations" section in Testing and Adjusting, "Operational Checks".
| NOTICE |
|---|
Ensure that the maximum allowable engine rpm for the heavy lift is set to the proper value of 1250 ± 50 rpm. Higher rpm settings can result in serious damage to the machine. |
- Install a laptop computer (M300 Technician) to the service connector (1) .
Note: Refer to Special Instruction, REHS0701, "Instructions for the Use of the M300 Technician Software with a Laptop Computer".
 | |
| Illustration 1 | g00293665 |
Left side of cab seat (1) Service connector | |
- Start the engine.
- Start M300 Technician.
- Move the heavy lift switch to the ON position.
- With the AEC switch in the OFF position, place the engine speed dial in the HIGH IDLE position.
- Select the "Status" button on the screen with the mouse.
- Select "Engine Speed".
- Select the "OK" button on the screen with the mouse.
- Check the engine rpm.
Note: The engine rpm should be 1250 ± 50 rpm. If the engine speed is not within the specifications, consult your AVSpare dealer.
Test (PDT)
- Prior to any adjustment, refer to the "Preparations" section in Testing and Adjusting, "Operational Checks".
| NOTICE |
|---|
Ensure that the maximum allowable engine rpm for the heavy lift is set to the proper value of 1250 ± 50 rpm. Higher rpm settings can result in serious damage to the machine. |
- Install the 123-6471 Diagnostic Tool Group to the service connector (1) .
Note: Refer to Special Instruction, SEHS9825 for the use of the 123-6471 Diagnostic Tool Group .
| | |
| Illustration 2 | g00293665 |
Left side of cab seat (1) Service connector | |
- Start the engine.
- Move the heavy lift switch to the ON position.
- With the AEC switch in the OFF position, place the engine speed dial in the HIGH IDLE position.
- Select the "Proc" mode. Use the arrow keys to select the "engine rpm" function on the PDT.
- Check the engine rpm.
Note: The engine rpm should be 1250 ± 50 rpm. If the engine speed is not within the specifications, consult your AVSpare dealer.
Pressure Test (Heavy Lift ON and Heavy Lift OFF)
- Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (2) .
 | |
| Illustration 3 | g00642936 |
The pressure tap is located in the battery compartment. (2) Load sensing signal pressure | |
- Start the engine.
- Place the engine speed at the HIGH IDLE position.
- Place the power mode switch in the MODE II position.
- Place the heavy lift switch in the ON position.
- Lower the left console.
- Slowly move the bucket control lever to the full BUCKET CLOSE position. Check the load sensing signal pressure at pressure tap (2). Refer to Testing and Adjusting, "Specifications" for the correct load sensing signal pressure with heavy lift.
- Place the heavy lift switch in the OFF position.
- Slowly move the bucket control lever to the full BUCKET CLOSE position. Check the load sensing signal pressure at pressure tap (2). Refer to Testing and Adjusting, "Specifications" for the correct load sensing signal pressure without heavy lift.
- Stop the engine.
Adjustment for Load Sensing Signal Limiter Valve
- Loosen the hose from signal limiter valve (9) .
 | |
| Illustration 4 | g00821187 |
(A) Main control valve (3) Adjustment nut (4) Locknut (5) Piston (6) Spindle (7) Locknut (8) Spool (9) Signal limiter valve | |
- Loosen locknut (4) .
- Turn adjustment nut (3) clockwise until the nut contacts the stop in order to block piston (5) .
Note: When adjustment nut (3) is turned in, signal pressure from the heavy lift solenoid valve is no longer required to achieve the pressure specification for heavy lift. The test should be done with the heavy lift switch in the OFF position.
- Tighten nut (4) while spindle (6) is held.
Adjustment for Heavy Lift Pressure
- Start the engine.
- Place the engine speed dial in the HIGH IDLE position.
- Place the heavy lift switch in the OFF position.
- Lower the left console.
- Loosen locknut (7) .
- Slowly move the bucket control lever to the full BUCKET CLOSE position. Check the load sensing signal pressure at pressure tap (2). Refer to Testing and Adjusting, "Specifications" for the correct load sensing signal pressure with heavy lift.
| | |
| Illustration 5 | g00642936 |
The pressure tap is located in the battery compartment. (2) Load sensing signal pressure | |
- To adjust the maximum pressure for the heavy lift, turn spindle (6). Turning the spindle counterclockwise will decrease the pressure and turning the spindle clockwise will increase the pressure.
Note: Make the final pressure adjustments on the pressure rise.
- Tighten locknut (7) by holding spindle (6) .
Adjustment for Normal Operating Pressure with Heavy Lift OFF
- The heavy lift switch must be in the OFF position.
| | |
| Illustration 6 | g00821187 |
(A) Main control valve (3) Adjustment nut (4) Locknut (5) Piston (6) Spindle (7) Locknut (8) Spool (9) Signal limiter valve | |
- Loosen locknut (4) .
- Slowly move the bucket control lever to the full BUCKET CLOSE position. Check the load sensing signal pressure at pressure tap (2). Refer to Testing and Adjusting, "Specifications" for the correct load sensing signal pressure without heavy lift.
- To adjust the maximum pressure for the heavy lift OFF, turn nut (3). Turning the nut counterclockwise will decrease the pressure and turning the nut clockwise will increase the pressure.
Note: Make the final pressure adjustments on the pressure rise.
- Tighten locknut (4) by holding nut (3) .
- Tighten the hose from signal limiter valve (9) .
Note: For the assembly of the hose and the fitting at the port, hold nut (3) .
Torque
-
(3) Nut ... 10 ± 1 N·m (7.4 ± 0.7 lb ft) (4) Nut ... 10 ± 1 N·m (7.4 ± 0.7 lb ft) (6) Spindle ... 10 ± 1 N·m (7.4 ± 0.7 lb ft) (7) Locknut ... 10 ± 1 N·m (7.4 ± 0.7 lb ft)