Grab, Accumulate, and Wrist Pressure Adjustment Procedure for HF201B and HF221A Felling Heads on Certain Track Feller Bunchers{5051, 5057, 5070, 5264, 5479} Caterpillar

Track Feller Buncher:

521B (S/N: F7B257-UP)

522B (S/N: F7C218-UP)

541 Series 2 (S/N: F7D1-UP)

552 Series 2 (S/N: F7G1-UP)

Introduction

This Special Instruction describes the procedure to adjust the valve to the correct setting for the grab, accumulate, and wrist pressures on 521B, 522B, 541 Series 2, and 552 Series 2 Track Feller Bunchers equipped with the standard feller buncher arrangement or with a harvester arrangement. If you need more information about the adjustment procedure for the grab, accumulate and the wrist pressures, consult your Caterpillar Dealer.

Note: The following procedure is used for the adjustment of both the standard feller buncher arrangements and for harvester arrangements.

Safety Section

Illustration 1	g00104545

Attach a "Do Not Operate" warning tag or a similar warning tag to the start switch or to the control before you service the equipment. These warning tags (Special Instruction, SEHS7332) are available from your Caterpillar dealer.

Do not perform any procedure in this Special Instruction until you have read this Special Instruction and you understand this information. Use only proper tools and observe all precautions that pertain to the use of those tools. Failure to follow these procedures can result in personal injury. The following procedures should also be observed.

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.

A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools in order to perform these functions properly.

Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.

Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. Ensure that any tool, procedure, work method, or operating technique you use that is not recommended by Caterpillar is safe.

Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or repair procedures used.

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Improper operation of an access platform could result in injury or death. Operators must carry out their duties properly and follow all instructions and guidelines given for the machine and access platform.

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility.

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Be sure all personnel are clear of the equipment while the equipment is being lowered. Failure to stay clear of the equipment while the equipment is being lowered may result in personal injury.

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Personal injury or death can result from sudden machine movement. Sudden movement of the machine can cause injury to persons on or near the machine. Prevent possible injury by performing the procedure that follows before working on the machine. Move the machine to a smooth and level location that is away from working machines and personnel. Ground all implements. Engage the parking brake. Stop the engine. Move the hydraulic control levers to all positions to release the pressure in the hydraulic system. To avoid accidental engine starting, turn the battery disconnect switch to the OFF position. Remove the key for the battery disconnect switch. Use a secure padlock in order to lock the battery compartment access door. Place a "Do Not Operate" tag at the Start/Stop switch location to inform personnel that the equipment is being worked on.

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Personal injury can result from hot coolant, steam and alkali. At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns. Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand. Cooling System Conditioner contains alkali. Avoid contact with skin and eyes.

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manuals. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Cat dealer for replacement manuals. Proper care is your responsibility.

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Personal injury or death can result from improperly checking for a leak. Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing 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.

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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 attachments have been lowered, 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.

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Accidental machine starting can cause injury or death to personnel working on the machine. To avoid accidental machine starting, turn the battery disconnect switch to the OFF position and remove the key. If the machine is not equipped with a battery disconnect switch, disconnect the battery cables from the battery and tape the battery clamps. Place a do not operate tag at the battery disconnect switch location to inform personnel that the machine is being worked on.

Illustration 2	g00037860

Use steps and handholds whenever you mount the machine. Use steps and handholds whenever you dismount the machine. Before you mount the machine, clean the step and the handholds. Inspect the step and handholds. Make all necessary repairs.

Face the machine whenever you mount the machine and whenever you dismount the machine. Maintain a three-point contact with the step and with handholds.

Note: Three-point contact can be both feet and one hand or a single foot and two hands.

Do not mount a moving machine. Do not dismount a moving machine. Never jump off the machine. Do not try to mount the machine when you carry tools or supplies. Do not try to dismount the machine when you are carrying tools or supplies. Use a hand line to pull equipment onto the platform. Do not use any controls as handholds when you enter the cab or when you exit the cab.

Machine Preparation

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility.

In addition to the normal safety precautions that are taken in the day to day operation of heavy machinery, the following steps are recommended:

1. Move the machine to a suitable location. The location should be smooth, level, and out of direct sunlight.

2. Move away from other working machines and personnel.

3. Ground all implements.

4. Stop the engine.

5. Engage the machine brake. Put blocks in front of the wheels and behind the wheels.

6. Turn the engine start switch key to the ON position but do not start the engine before performing step 7.

7. Move the implement control levers through the full range of travel. This procedure will relieve any pressure that may be present in the implement hydraulic system.

8. Depress the brake pedal repeatedly. This procedure will relieve any pressure that may be present in the brake hydraulic system.

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

10. Allow several minutes for steering system pressure to release.

11. When possible, maintain ownership of the machine keys.

Consult the Machine Operation and Maintenance Manual for all safety procedures applicable to the specific machine being worked on before performing any repairs or diagnostics.

Required Tools

Illustration 3	g03410699

Adjustment Procedure

Illustration 4	g03410702
(B) Pressure Gauge (C) 307-1696 Piston Pump Gp

1. Warm the hydraulic oil to normal operating temperature. Normal operating temperature is 45° C (113° F) to 70° C (158° F).

2. To warm the hydraulic fluid using the following:
   • Operate the engine at 1800 rpm to 2000 rpm

   • Extend the boom cylinder up and down

   • Operate the tilt cylinder or the tilt motors back and forth until normal operating temperature is reached

   Note: Do not hold any function in the stalled position for more than 10 seconds. Hydraulic oil is heated rapidly when the oil is forced over the relief valve. Component damage could result.

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Illustration 5	g03432957
Main control valve

3. Attach 177-7862 Hose As and the 8T-0860 Pressure Gauge to the proper pressure tap for the function that is being operated. Refer to Illustration 5.

4. Actuate the function until the function is in the stalled state.

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Illustration 6	g03434140
Main implement pump with pressure gauge attached (B) Pressure gauge

5. Record the pressure on the pressure gauge while the function is stalled. Refer to Illustration 6.

6. Operate the wrist/rotate function of the felling head both clockwise (CW) and counterclockwise (CCW) rotation.

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Illustration 7	g03434067
Control valve (D) Feed reducing adjustment

7. Loosen the jam nut on the implement feed reducer. While the operator pushes the wrist CW button, adjust the implement feed reducer on the wrist valve. Set pressure to the proper setting based on either the Partial or Full Tilt HF201B or HF221A Felling Head. Refer to Table 1 Retighten the jam nut on the feed reducer.

8. Repeat step 7 for the CCW button and adjustment to the feed reducer on the wrist valve using either the Partial or Full Tilt HF201B or HF221A Felling Head.

9. Repeat steps 1 through step 8. Refer to table 1.

Specification Table