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Hydraulic oil that is hot, and under pressures that can be as high as 415 bar, 41 500 kPa, (6000 psi) can remain in the hydraulic systems on this machine after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to section, RELEASING PRESSURE IN THE PILOT SYSTEM, before any fitting, hose or component is loosened, tightened, removed or adjusted. When possible, the bucket must always be lowered to the ground before service is started. When it is necessary for the boom to be raised while tests or adjustments are done, be sure that boom and stick have correct support and the bucket is in the full open position. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made. |
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NOTE: The engine rpm information is to be used as a guide only, the actual rpm may vary between machines.
In an analysis of machine performance, comparison of engine rpms under different conditions of loading is of very little value. There are conditions, however, when a change in engine rpm can be an indication of the cause of a problem.
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Serious injury or death by electrocution can result if the machine or attachments are not kept a safe distance from electrical power lines. Keep the distance at least 3.05 m (10 feet) plus an additional 10 mm (.4 in.) for each 1,000 volts over 50,000 volts. For safety, local or state codes or jobsite operating directives, may require a greater distance. Never swing a load over a truck cab or workers. |
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Release of Pressure In The Pilot System
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To prevent personal injury, release the pressure in the implement hydraulic circuits (boom, stick and bucket) before any hydraulic lines or components are disconnected or removed. Be careful of hot oil. Follow this procedure: |
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1. Fully retract the rod in the stick cylinder.
2. Adjust the position of the bucket so that it will be flat on the ground when the boom is lowered.
3. Lower the boom until the bucket is flat on the ground.
4. Shut off the engine and put the lever for the lock valve in the locked position.
5. Move the control levers for boom, bucket, stick and swing to all positions. This will relieve any pressure that might be present in the pilot system.
6. Slowly loosen the filler cap on the hydraulic tank and release the pressure.
7. Tighten the filler cap back on the hydraulic tank.
8. The pressure in the system should now have been released and lines and components can be removed.
NOTE: There are no bleed valves in the circuits. Normally, any pressure that might be trapped in these lines will bleed off through the motors or through tank.
Instructions For Testing And Adjusting
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Make reference to WARNING on first page of the TESTING AND ADJUSTING Section. |
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NOTE: Make these tests when the hydraulic oil is at normal temperature of operation. (1 Bar is equal to 100 kPa; 6.9 kPa is equal to 1 psi; 1 Bar is equal to 14.5 psi)
Left Valve Bank Components (Typical Example)
1. Return line to hydraulic tank. 2. Stick crossover valve. 3. Valve for left track. 4. Line relief valve for the bucket cylinder. 5. Control valve for the bucket cylinder. 6. Line relief valve for boom cylinders. 7. Control valve for boom cylinders. 8. Pressure tap (quick disconnect) for checking main relief valve pressure on the left valve bank. 9. Adjustment screw for adjusting main relief pressure. 10. Main pump supply (front pump). 11. Return line to tank.
Main Relief Valve On Left Valve Bank
Connect a pressure gauge to gauge connection (quick disconnect) (8) of left valve bank. Run engine at normal operating speed. Retract bucket cylinder up to the limit stop. Then the pressure should be 300 bar (30 000 kPa). Adjust the pressure by turning the adjustment screw (9) on the main relief valve on the left hand valve bank.
Line Relief Valve On Left Hand Valve Bank
a. Connect a pressure gauge to gauge connection (quick disconnect) (8) of left hand valve bank. Run engine at a 1200 rpm speed. Lock the swing drive with the pin. Swing to the left or to the right against the lock.
NOTE: In order to check the line relief pressure, the main relief valve will have to be set higher than the line relief setting each time. Be sure to reset the main relief back to its correct setting each time.
1. Check Line relief valve for boom cylinder extension = 350 bar (35 000 kPa)
Extend the boom cylinders fully against their limit stop.
b. Turn the adjustment screw on main relief valve of left valve bank until the pressure gauge indicator stops rising. The indicator should now show the specified pressure. The pressure is corrected by means of shims located between the cap and spring of the line relief valve (6). Now reset the primary relief valve (9) at 300 bar (30 000 kPa).
2. Check the line relief valve for boom cylinder retraction = 325 bar (32 500 kPa)
Carry out instruction a, retract the boom cylinders with shutoff valve closed (from operator's compartment) and carry out instruction b.
NOTE: In order to check the line relief pressure, the main relief valve will have to be set higher than the line relief setting each time. Be sure to reset the main relief back to its correct setting each time.
3. Check line relief valve (4) for bucket cylinder extension = 325 bar (32 500 kPa).
Carry out instruction a, extend the bucket cylinder against the stop, and carry out instruction b.
4. Check line relief valve (4) for bucket cylinder retraction = 325 bar (32 500 kPa).
Carry out instruction a, retract bucket cylinder against the stop and carry out instruction b.
Line Relief Valve On Right Hand Valve Bank
Right Valve Bank Components (Typical Example)
12. Bucket and boom crossover valve. 13. Return line for hydraulic oil cooler. 14. Control valve for the right track. 15. Line relief valve for the stick cylinder. 16. Control valve for the stick cylinder. 17. Control valve for swing circuit. 18. Implement supply (rear pump). 19. Pressure tap (quick disconnect) for checking main relief valve pressure on the right valve bank. 20. Adjustment screw for adjusting main relief pressure.
Connect a pressure gauge to gauge connection (quick disconnect) (19) of right hand valve bank. Run engine at normal operating speed. Retract or extend the stick cylinder fully against the stop. Then the pressure should be 300 bar (30 000 kPa). Adjust pressure by turning the adjustment screw (20) on the main relief valve of the right hand bank.
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Because of the compound circuit, both main relief valves (left and right) are operative, and only the lower set pressure is indicated. Therefore, slowly increase pressure with the adjusting screw until pressure rises to 300 bar (30 000 kPa). |
5. Check the line relief valve on right hand valve bank.
c. Connect a pressure gauge to gauge connection (quick disconnect) (19) of right hand valve bank. Run engine at 1200 rpm. Retract bucket cylinder fully against the stop.
6. Check the line relief valve (15) for stick cylinder extension = 350 bar (35 000 kPa).
NOTE: In order to check the line relief pressure, the main relief valve will have to be set higher than the line relief setting each time. Be sure to reset the main relief back to its correct setting each time.
Extend the stick cylinder fully against the stop.
d. Turn the adjustment screw (20) on the main relief valve of the right hand valve bank until the pressure gauge indicator stops rising. The indicator should now show the specified pressure. The pressure is corrected by means of shims located between the cap and the spring of the line relief valve (15). Now reset the main relief valve (20) to 300 bar (30 000 kPa).
7. Check line relief valve for stick cylinder retraction = 350 bar (35 000 kPa).
Carry out instruction c, retract stick cylinder fully against the stop and carry out instruction d.
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Make reference to WARNING on first page of the TESTING AND ADJUSTING Section. |
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NOTE: Make these tests when the hydraulic oil is at normal temperature of operation. (1 Bar is equal to 100 kPa; 1 Bar is equal to 14.5 psi; 1 psi is equal to 6.9 kPa.)
Relief Valves On The Hydraulic Swing Drive Motor
Connect a pressure gauge to gauge connection (quick disconnect) (19) of right hand valve bank. Run the engine at normal operating speed.
8. Check line relief valve for hydraulic swing drive motor - CW swing = 250 bar (25 000 kPa), 205 and 210 bar (21 000 kPa) for 211.
Lock the upper stricture with pin, swing to the right and run hydraulic motor against the limit stop. The pressure gauge should now indicate the specified pressure. The pressure is corrected by means of an adjustment screw.
9. Check the line relief valve for hydraulic swing drive motor - swing to the left = 250 bar (25 000 kPa), 205 and 210 bar (21 000 kPa) for 211.
Lock the upper carriage with the pin, swing to the left and run hydraulic motor against the stop. The pressure gauge should now indicate the specified pressure. The pressure is corrected by means of an adjustment screw.
NOTE: The line relief valves for left and right swing operate as main relief valves. When checking pressure, run engine against the stop at maximum speed without jolting (jerky) effect (sensitive control - upper structure locked with the pin).
10. Pressure relief valve on basic cooling block 80 bar (8000 kPa), maximum.
The pressure setting 80 bar (8000 kPa) of this relief valve is substantially above the operating pressure (20 bar, 2000 kPa) of the cooler motor. Therefore, setting or checking is required only in exceptional cases, and in case of possible damage (see the topic, Basic Cooling Block).
For pressure adjustment, the connection between basic cooling block and fan motor must be blocked. Connect the pressure gauge to basic cooling block. Run engine at normal operating speed. The gauge should now indicate the specified pressure. Pressure correction is achieved by means of the adjustment screw. Turning-in results in pressure rise, turning-out in a pressure reduction.
11. The main relief valve on the control valve bank for optional actuators equipped) is set at 200 bar (20 000 kPa).
Do not connect optional actuators for pressure adjustment. Connect a pressure gauge to the gauge connection of basic cooling block. Run engine at normal operating speed. Activate optional attachment function by left hand or right hand switch. Turn the adjustment screw of the main relief valve out until the pressure gauge indicator stops rising. The gauge should indicate the specified pressure. Both sides must show the same pressure. Pressure correction is achieved by means of the adjustment screw. Turning-in results in pressure rise, turning-out in pressure reduction (see the topic, Control Valve Bank, Optional Actuators). Finally, reset the main relief valve to 200 bar (20 000 kPa).
12. Line relief valves on control valve bank for optional actuators. 2 @ 300 bar (30 000 kPa), if equipped.
13. Pressure reducing valve, gear shift valve bank 13 bar (1300 kPa). Connect a pressure gauge to gauge connection, gear shift valve bank. Run engine at normal operating speed. The gauge should now indicate the specified pressure. Pressure correction is achieved by means of the adjustment screw. Turning-in results in pressure rise, turning-out in pressure reduction (see the topic, Control Valve Bank, Gear Shifting).