416D, 420D, 424D, 428D, 430D, 432D, 438D and 442D Backhoe Loaders Hydraulic and Steering System Caterpillar

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

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Personal injury or death can result from escaping fluid under pressure. Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak.

Illustration 1	g00744000
(1) Hydraulic pump (2) Flow compensator valve (3) Pressure compensator valve (4) Signal pressure tap

Signal pressure tap (4) is located on hydraulic pump (1) . Flow compensator valve (2) and pressure compensator valve (3) are also located on hydraulic pump (1) . Access is gained from the bottom of the machine or access is gained by removing the floorplate.

Illustration 2	g00778422
(5) System pressure tap

The system pressure tap (5) is located on the block for the pump discharge pressure. Access is gained from the bottom of the machine.

Pump discharge pressures are known values. The pump discharge pressures can be tested during two specific conditions.

• low-pressure standby

• high-pressure stall

Prior to making any pump adjustments, perform "Low Pressure Standby Test", "Margin Pressure Test" and "High Pressure Stall Test".

Increase the hydraulic oil temperature to the operating temperature by installing the boom lock and stalling the boom down for 60 seconds. Check for leaks.

Assembly of the Hose Assemblies

1. Install one 6V-4143 Coupler to each end of the 177-7860 Hose Assemblies .

2. Install one 6V-3989 Fitting to each pressure gauge.

Low Pressure Standby Test

1. Start the engine.

2. Lower the work tool on the front of the machine and the stabilizers to the ground. Engage the parking brake. Stop the engine.

3. Turn the engine start switch key to the ON position.

4. Move the hydraulic hand controls to all the positions in order to release system pressure.

5. Turn the engine start switch key to the OFF position.

6. Remove the metal floorplate and the floor mat.
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   Illustration 3	g00869466

   1. Remove two bolts (6) and plate (7) .
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   Illustration 4	g00869467

   2. Remove two bolts (8) and plate (9) . Remove floor mat (10) .
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   Illustration 5	g00869469

   3. Remove four bolts (11) and set the floorplate (12) aside.

7. Install the 8T-0856 Pressure Gauges with a range of 0 to 6000 kPa (0 to 870 psi) to each hose assembly. Install one hose assembly to the pressure tap (5) for system pressure. Install one hose assembly to the signal pressure tap (4) .

   Note: Do not move any hydraulic hand controls or the steering wheel while the 8T-0856 Pressure Gauges are installed. The higher pressure that is created by upstroking the pump will damage the gauges.

8. Start the engine. Run the engine at HIGH idle. Check for leaks.

9. Do not move any hydraulic hand controls nor move the steering wheel. The pressure reading on the gauge that is attached to the pressure tap (5) for the system pressure should be 2850 ± 750 kPa (415 ± 110 psi). This pressure is the low pressure standby pressure. For best results, the low standby pressure should be set at approximately 3100 kPa (450 psi).

10. The pressure reading on the gauge that is attached to the signal pressure tap (4) should be approximately 650 kPa (95 psi). This pressure is the steering signal pressure. The steering signal pressure is not adjustable.

    Note: The steering signal pressure will vary with each machine. The steering signal pressure of each machine should remain consistent with the previous readings on that machine.

11. Stop the engine.

12. Before continuing to the next test, remove the two 8T-0856 Pressure Gauges from both hose assemblies. Install a 8T-0860 Pressure Gauge with a range of 0 to 40000 kPa (0 to 5800 psi) to the hose assembly that is attached to the pressure tap (5) and to the pressure tap (4) .

    Note: Failure to remove the 8T-0856 Pressure Gauges prior to performing the following tests will cause the gauges to be destroyed, when the pump is upstroked.

Margin Pressure Test

1. Start the engine. Run the engine at HIGH idle.

2. Engage the boom lock. Stall the boom circuit with a one-third lever movement in the DOWN position.

3. Subtract the pressure at signal pressure tap (4) from the pressure at system pressure tap (5) . This result is the margin pressure. The margin pressure should be 2200 ± 350 kPa (320 ± 50 psi).

4. Stop the engine.

5. If margin pressure or standby pressure is not correct, the flow compensator valve must be adjusted.

6. Do not adjust the flow compensator spool based on the results of this test. Perform the "High Pressure Stall Test" before you adjust the flow compensator spool.

High Pressure Stall Test

1. Install the swing lock pin and install the boom lock.

2. Start the engine. Run the engine at LOW idle.

3. Ensure that the work tool on the front of the machine and the stabilizers are on the ground. Engage the parking brake.

4. Move the hydraulic hand controls one at a time in order to initiate a stall condition for the circuits in Table 2. Note the pressure reading at pressure tap (4) for each circuit.

5. See Table 2 for the proper pressure readings at pressure port (4) .
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   Table 2

   Hydraulic Circuit	420D, 428D, 430D, 432D, 438D and 442D	416D and 424D
   STICK OUT	22800 ± 700 kPa (3300 ± 100 psi)	20700 ± 700 kPa (3000 ± 100 psi)
   STICK IN
   STICK EXTEND (if equipped)
   STICK RETRACT (if equipped)
   Auxiliary (if equipped)
   SWING
   Backhoe BUCKET DUMP
   Backhoe BUCKET CLOSE
   BOOM RAISE
   BUCKET DUMP (parallel lift machines)	16200 ± 700 kPa (2350 ± 100 psi)	N/A
   RACK BACK (parallel lift machines)	22800 ± 700 kPa (3300 ± 100 psi)
   BUCKET DUMP and RACK BACK for (S/N: FDP1-7198, BNK1-2501)
   BUCKET DUMP and RACK BACK for (S/N: FDP7199-UP, BNK2502-UP)	15400 ± 800 kPa (2230 ± 120 psi)
   BUCKET DUMP and RACK BACK (single tilt machines)	22800 ± 700 kPa (3300 ± 100 psi)	20700 ± 700 kPa (3000 ± 100 psi)
   LIFT

   Note: There may be air in the signal network, if there is a hesitation before reaching the relief pressure. Purge the signal lines of the air.

6. In order to check the BOOM LOWER circuit, perform the following procedure.

   1. Engage the boom lock.
      • For 416D, 420D, 424D and 430D machines, run the engine at 1100 rpm. Activate the BOOM LOWER by pushing the boom control lever fully forward.

      • For 428D, 432D, 438D and 442D machines, run the engine at 1250 rpm. Activate the BOOM LOWER by pushing the boom control lever fully forward.

   2. Note the pressure reading at pressure tap (4) .

   3. See Table 3 for the proper pressure readings at pressure port (4) .
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      Table 3

      Hydraulic Circuit	420D, 428D, 430D, 432D, 438D and 442D	416D and 424D
      BOOM LOWER	15200 ± 700 kPa (2200 ± 100 psi)	15500 ± 700 kPa (2250 ± 100 psi)

7. If the machine is equipped with All Wheel Steer, perform the following procedure.
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   Illustration 6	g00869579
   (13) All Wheel Steer switch

   1. Check the circuit for the All Wheel Steer by moving the All Wheel Steer switch (13) to the right.
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   Illustration 7	g00869580
   The Independent Rear Maneuvering switches are located on the pilot operated controls. (14) Pilot operated loader control (15) Left Independent Rear Maneuvering switch (16) Right Independent Rear Maneuvering switch

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   Illustration 8	g00869582
   The Independent Rear Maneuvering switches are located on the mechanically operated controls. (14) Mechanically operated loader control (15) Left Independent Rear Maneuvering switch (16) Right Independent Rear Maneuvering switch

   2. Stall the rear axle by pressing the left Independent Rear Maneuvering switch (15) or the right Independent Rear Maneuvering switch (16) .

   3. Note the pressure reading at pressure tap (4) .

   4. See Table 4 for the proper pressure readings at pressure port (4) .
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      Table 4

      Hydraulic Circuit	420D, 430D, 438D and 442D	416D, 424D, 428D and 432D
      Independent Rear Maneuvering	22800 ± 700 kPa (3300 ± 100 psi)	N/A

8. Turn off the engine. Engage the parking brake and remove the test equipment.

9. If the BOOM LOWER, RACK BACK or DUMP pressures are not within the specification, check the line relief valve of the suspected function.

10. If the RACK BACK or DUMP pressure is not with the specification for these machines (S/N: FDP7199-UP, BNK2502-UP), check the relief valve for the signal pressure on the tilt control valve.

11. If the pressure for any other circuit is not within the specification, adjust the pressure compensator valve.

12. If the engine stalls, adjust the torque limiter.

13. Stop the engine and remove the gauges.

The Relief Valve for the Tilt Cylinder (Bucket Dump and Rackback)

Refer to the following steps in order to check the pressure setting:

1. Attach 8T-0857 Pressure Gauge to the output pressure port on the hydraulic pump.

2. Start the machine.

3. Tilt the bucket to the DUMP position or tilt the bucket to the RACK BACK position. Hold the valve in the open position.

   Note: The valve functions when the control spool is actuated.

4. Read the pressure gauge in order to determine the relief valve setting. See table 2 for the correct pressure for your machine.

Adjustments for the Pump Controller

Illustration 9	g00844826
Compensator valve (all other machines) (1) Flow compensator (3) O-ring (4) Locknut (5) Adjustment screw (6) Cap (7) Adjustment screw (8) Cap (9) Locknut (10) O-ring (11) Pressure compensator spool (12) O-ring (13) O-ring

Note: If an adjustment is necessary, replace the O-rings (3) , (10) , (12) and (13) . Replacing the O-rings will reduce the possibility of oil leakage after an adjustment to the compensator valve is made.

Flow compensator valve (1) and pressure compensator valve (11) have been tested by running the pump discharge tests.

Adjustment For The Pressure Compensator Spool

Adjustments to the pressure compensator spool can be made on the machine. If the "High Pressure Stall Test" is within the specification, then go to the Flow Compensator Spool Adjustment. If the "High Pressure Stall Test" is not within the specification, then do the following procedure.

1. Ensure that the work tool on the front of the machine and the stabilizers are on the ground. Engage the parking brake.

2. Stop the engine.

3. Turn the engine start switch key to the ON position.

4. Move all of the hydraulic hand controls to all of the positions. This process releases the system pressure.

5. Turn the engine start switch key to the OFF position.

6. Remove cap (13) and loosen locknut (14) . Turn adjusting screw (12) clockwise in order to increase the pressure setting. Turn adjusting screw (12) counterclockwise in order to decrease the setting.

7. Install a 8T-0860 Pressure Gauge with a range of 0 to 40000 kPa (0 to 5800 psi) to system pressure tap (4) .

8. Repeat the "High Pressure Stall Test" until the system pressure is within the specification.

9. When the pressure compensator is adjusted correctly, stop the engine. Tighten locknut (14) . Replace cap (13) and remove the gauges.

Flow Compensator Spool Adjustment

Adjustments to the flow compensator spool can be made on the machine. If the Margin Pressure and Low Pressure Standby pressures are within the specifications, then go to the Test and Adjustment for the Torque Limiter. If the Margin Pressure or Low Pressure Standby pressures are not within the specification, then do the following procedure.

1. Lower the work tool on the front of the machine and the stabilizers to the ground. Engage the parking brake.

2. Stop the engine.

3. Turn the engine start switch key to the ON position.

4. Move all the hydraulic hand controls through all of the positions in order to release pressure in the hydraulic system.

5. Turn the engine start switch key to the OFF position.

6. Install two 8T-0856 Pressure Gauges with a range of 0 to 6000 kPa (0 to 870 psi) to the pressure tap (5) for the system pressure and to signal pressure tap (4) .

   Note: Do not move any hydraulic hand controls nor move the steering wheel while the 8T-0856 Pressure Gauge is installed. The higher pressure that is created by upstroking the pump will damage the gauge.

7. Repeat the "Low Pressure Standby Pressure Test".

8. If the low pressure standby pressure is within the specifications, then go to Step 11. If the low pressure standby pressure is not within the specifications, then remove cap (6) and loosen locknut (9) . Turn adjusting screw (10) clockwise in order to increase the pressure setting. Turn adjusting screw (10) counterclockwise in order to decrease the pressure setting.

9. Repeat the "Low Pressure Standby Pressure Test" until the low pressure standby pressure is within the specification.

10. Tighten locknut (9) and replace cap (11) .

11. Lower the implements to the ground. Stop the engine and engage the parking brake.

12. Remove all test equipment.

13. Repeat the "Margin Pressure Test" in order to check that the margin pressure is still within the specification.

Test for the Torque Limiter

Note: The following procedure can be used in most cases when the torque limiter may be the cause of a performance problem.

Note: Install a 9U-7400 Multitach to the engine. Check the low idle. The low idle must be 975 ± 25 rpm. If the engine low idle rpm is not within the specification, then refer to Systems Operation, Testing and Adjusting, SENR5816, "3054 Engine for Caterpillar Built Machines". Perform the low idle adjustment. The engine idle must be within the specification before continuing to the next procedure.

Note: Perform "Low Pressure Standby Pressure Test", "Margin Pressure Test" and "High Pressure Stall Test" prior to performing the Test for the Torque Limiter. Make the necessary adjustments in order to meet the specifications.

Perform the following tests before you adjust the torque limiter.

Perform the test for the torque limiter on single tilt machines and parallel lift loaders.

1. Ensure that the work tool on the front of the machine and the stabilizers are on the ground. Engage the parking brake.

2. Start the engine. Run the engine at LOW idle.

3. Place the transmission in SECOND gear. Activate the front running lights. Activate the air conditioner (if equipped).

4. Engage the service brakes.

5. Perform the appropriate test.

   1. For single tilt machines, rack back the bucket fully and lower the bucket to the ground. Activate the LIFT circuit slowly. Note the pressure while the lift arms are moving. Do not stall the LIFT circuit.

   2. For parallel lift machines, dump the bucket fully and lower the bucket to the ground. Stall the DUMP circuit and activate the LIFT circuit slowly. Note the pressure while the lift arms are moving. Do not stall the LIFT circuit.

6. Stop the engine.

7. If the engine does not stall, no adjustment to the torque limiter is necessary.

8. If the engine stalls, the torque limiter on the hydraulic pump is set too high or the engine has low power. Lower the work tool to the ground. Stop the engine and engage the parking brake. Adjust the torque limiter by performing Step 16 through Step 21 of the "Test and Adjust the Torque Limiter with a Flow Meter" procedure. Then, repeat the test procedure. If the engine stalls, adjust the fuel pump for the engine.

Optional Test for the Torque Limiter

Perform the BOOM DOWN circuit test for the torque limiter on backhoe loaders.

1. Ensure that the work tool on the front of the machine and the stabilizers are on the ground. Engage the boom lock. Engage the parking brake.

2. Start the engine. Run the engine at 1100 rpm.

3. Activate the BOOM DOWN circuit. Stall the circuit.

4. If the engine does not stall, no adjustment to the torque limiter is necessary. Stop the engine and engage the parking brake.

5. If the engine stalls, the torque limiter on the hydraulic pump is set too high or the engine has low power. Lower the work tool to the ground. Stop the engine and engage the parking brake. Adjust the torque limiter by performing Step 16 through Step 21 of the "Test and Adjust the Torque Limiter with a Flow Meter" procedure. Then, repeat the test procedure. If the engine stalls, adjust the fuel pump for the engine.

Test and Adjust the Torque Limiter with a Flow Meter

Note: This test should not be performed unless the "Test for the Torque Limiter" does not resolve the performance problem with the torque limiter.

Illustration 10	g00841651
(1) Pump pressure tap (2) Hydraulic pump

Pump pressure tap (1) is located on hydraulic pump (2) .

1. Start the engine. Engage the parking brake.

2. Move the stick OUT. Lower all the work tools and the stabilizers to the ground.

3. Stop the engine. Move all the control levers to all positions. This releases system pressure.

4. Install one 8T-0860 Pressure Gauge with a range of 0 to 40000 kPa (0 to 5800 psi) to one end of the 177-7860 Hose Assembly . Attach the second end of the hose assembly to pump pressure tap (1) .

5. Install one 8C-3417 Elbow into each port in 4C-9910 Flow Meter . Attach one 6V-8946 Reducer Assembly onto each 8C-3417 Elbow . Attach one 6V-8943 Reducer Assembly onto one of the 6V-8946 Reducer Assemblies .

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Illustration 11	g00747372
(5) Retainers

6. There are two retainers (5) on the boom. Remove the two bolts from each retainer. Remove the retainers.

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Illustration 12	g00747389
(6) Hose to the head end of the boom cylinder (7) Connector to the head end of the boom cylinder

7. Remove the hose (6) from the connector from the head end of the boom cylinder (7) . Install one 123-3893 Cap Assembly to connector (7) .

8. Install the hose to the head end of the boom cylinder (6) onto the 6V-8943 Reducer Assembly that was installed in Step 5.

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Illustration 13	g00747400
(8) Hose to the rod end of the boom cylinder (9) Tube to the rod end of the boom cylinder

9. Remove hose (8) from the tube to the rod end of the boom cylinder (9) . Install a 6V-9831 Cap Assembly to tube (9) .

10. Install the end of hose (8) onto the 6V-8946 Reducer Assembly that was installed in Step 5.

11. Start the engine. Cycle the work tools until the hydraulic oil temperature on the 4C-9910 Flow Meter rises to 60 °C (140 °F).

12. When the hydraulic oil temperature is at 60 °C (140 °F), increase the engine speed to 2200 rpm. Move the boom control lever to the boom RAISE position. Hold the boom control lever in the RAISE position. Flow will decrease as rpm decreases.

13. Rotate the control knob for the pressure on the 4C-9910 Flow Meter until the pump pressure is 17,900 kPa (2600 psi) at pump pressure tap (1) . Record the flow and the oil pressure.

    Note: If the engine cannot maintain 2200 rpm, refer to Systems Operation, Testing and Adjusting, SENR5815, "3054 Engine for Caterpillar Built Machines". Perform the torque converter stall test and check the high idle. The engine high idle must be within the specification before continuing to the next procedure.

14. Table 6 shows the correct pump pressure and the correct flow rate for 416D and 424D machines.
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    Table 6

    PUMP PRESSURE	FLOW
    17900 kPa (2600 psi)	102 ± 3 L/min (27 ± 1 US gpm)

    Table 7 shows the correct pressure and the correct flow rate for all other machines.

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    Table 7

    PUMP PRESSURE	FLOW
    17900 kPa (2600 psi)	120 to 140 L/min (31 to 37 US gpm)

15. If the flow is not within the specification, then adjust the torque limiter. Lower all work tools to the ground and stop the engine.

16. Turn the engine start switch key to the ON position.

17. Move all the hydraulic hand controls through all of the positions in order to release pressure in the hydraulic system.

18. Turn the engine start switch key to the OFF position.

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Illustration 14	g00747415
(10) Cap on the torque limiter

19. Remove cap (10) .

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Illustration 15	g00747419
(11) Locknut on the torque limiter (12) Plug on the torque limiter

20. Loosen locknut (11) . Turn plug (12) clockwise in order to increase the flow. Turn plug (12) counterclockwise in order to decrease the flow.

    Note: Use FT-2812 Modified Wrench for Adjusting the Torque Limiter .

    Note: Take care to loosen the locknut so that the sleeve will not bind. If the bolt dislodges from the sleeve, the sleeve does not rotate. If the sleeve does not rotate, no adjustment is made.

    Note: Turning the plug (12) to the next flat side of the plug will change the flow approximately 7.6 L/min (2 US gpm). Never, adjust plug (12) more than three and a half of a turn. Adjusting the plug (12) more may damage the internal spring. If the spring fails, the pump performance will be poor.

21. After the adjustment is made, tighten locknut (10) .

22. Repeat Steps 11, 12, 13 and 14.

23. If the flow is not within the specification, then repeat Steps 20 and 21. If the torque limiter is not within the specification after several attempts, then rework the torque limiter. Go to the next test in order to Rework the Torque Limiter. Repeat the test and adjust for the torque limiter after you rework the torque limiter.

24. When the flow is within the specification in Steps 14, then proceed with the next Step.

25. Turn the engine start switch key to the ON position.

26. Move all the hydraulic hand controls through all of the positions in order to release pressure in the hydraulic system.

27. Turn the engine start switch key to the OFF position.

28. Remove the test equipment.

29. Remove hose (6) from the 6V-8946 Reducer Assembly . Remove 6V-9831 Cap Assembly from tube (5) . Place a new O-ring onto the fitting and reinstall hose (6) to tube (5) .

30. Remove hose (4) from the 6V-8946 Reducer Assembly . Remove 6V-9832 Cap Assembly from elbow (3) . Place a new O-ring onto the fitting and reinstall hose (4) to elbow (3) .

31. Replace hoses (4) and (6) into the two retainers (8) on the boom for the two hoses. Reinstall the four bolts (7) . There are two bolts on each retainer (8) . Reinstall the retainers (8) on the boom for the hoses.

32. Replace the floorplate. Reinstall the four screws that hold the floorplate in place.

33. Reinstall the four screws that hold the two plates for the floor mat. There are two screws on each plate. The plates are located at the edge of each door in the cab.

Rework the torque limiter

Note: If the torque limiter cannot be set within the specification, then replace the torque limiter.

Note: This procedure will not increase the lifting capacity of the machine.

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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

1. Move the machine to a level surface.

2. Lower all of the work tools to the ground.

3. Turn the engine OFF. Engage the parking brake.

4. Turn the engine start switch key to the ON position.

5. Move all the hydraulic hand controls through all of the positions in order to release pressure in the hydraulic system.

6. Turn the engine start switch key to the OFF position.

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Illustration 16	g00747791
(1) Piston pump (2) Torque limiter (3) Bolts (4) Tube

7. Clean the area around torque limiter (2) .

8. Disconnect tube (4) from torque limiter (2) .

9. Remove the two bolts (3) .

   Note: Use FT-2812 Modified Wrench for Adjusting the Torque Limiter .

10. Remove torque limiter (2) from pump (1) .

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Illustration 17	g00850777
(5) Springs

11. Replace the springs (5) for the torque limiter and the O-rings for the torque limiter.

12. Clean all of the parts prior to assembly. Assemble the torque limiter.

13. Install the torque limiter (2) .

14. Install two bolts (3) .

15. Connect tube (4) to torque limiter (2) .

16. Repeat the Test for the Torque Limiter.

17. Check the hydraulic oil level. Refer to the Operation and Maintenance Manual for the proper capacity.