Testing and Reworking the Flow Control Valve{5051} Caterpillar

Backhoe Loader:

416D (S/N:: BGJ1-UP; BFP1-UP)

420D (S/N:: BLN1-UP; FDP1-UP; BMC1-UP)

424D (S/N:: RXA1-UP; CJZ1-UP)

428D (S/N:: BXC1-UP; MBM1-UP; DSX1-UP)

430D (S/N:: BNK1-UP; BML1-UP)

432D (S/N:: WEP1-UP; TDR1-UP)

438D (S/N:: BPE1-UP)

442D (S/N:: TBD1-UP; SMJ1-UP)

Introduction

ReferenceDisassembly and Assembly, RENR3585, "416D, 420D, 424D, 428D, 430D, 432D, 438D, and 442D Backhoe Loaders Machine Systems"

This Special Instruction contains the information that is needed for testing and reworking the flow control valve. The procedures in this instruction are performed on machines that have exhibited a loss in one or more of the following hydraulic circuits.

• Backhoe swing, extendable stick, and auxiliary function

• Loader tilt, lift, and auxiliary function

Note: Although the illustrations in this instruction only picture the backhoe valve, the procedures in this instruction are applicable to the loader valve as well.

Do not begin testing and reworking the flow control valve until you have read the information that is contained in this instruction.

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.

Testing for Replacement of the Spool

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At operating temperature, the hydraulic oil is hot and under pressure. Hot oils can cause burns. To prevent possible personal injury, release the pressure in the implement hydraulic circuit (boom, stick, bucket, and swing), travel circuits, and the hydraulic oil tank at the filler cap before any hydraulic lines or components are disconnected or removed. Remove the filler cap only when the engine is stopped and the filler cap is cool enough to touch.

Illustration 1	g01190411
Tools needed for testing and reworking the flow control valve (A) Torque wrench 70 N·m (50 lb ft) (B) Breaker Bar (C) Hammer (D) Extension Bar (E) Puller Tool (Dealer's choice) (F) 280-7987 Bore Gauge (G) 3/8 inch hex bit socket

Note: The puller tool that is shown in Illustration 1 is an 8 inch bolt. Any object that will enable you to withdraw the spool and the spring from the valve can be used.

1. Remove dirt and remove debris from the top of the valves. Use compressed air only.

   Note: Do not use solvents for cleaning the top of the valve. Solvents can remove the paint from the valves.

2. Locate the flow control valve on the valve section for the failed function.

3. Remove the plug in the top of the flow control valve:
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   Illustration 2	g01190413

   1. Install the 3/8 inch hex bit socket onto the extension bar and insert the bit into the head of the plug. Tap the extension with a hammer in order to seat the bit into the plug.
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   Illustration 3	g01190414

   2. Assemble the breaker bar to the extension. Exert force in a counterclockwise direction in order to break the plug's seal. Then, unscrew and remove the plug.

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Illustration 4	g01190432

4. Insert the puller tool into the valve. Maneuver the puller tool in order to grasp the inside lip that is located on the top of the spool. Carefully withdraw the spool from the valve.

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Illustration 5	g01190428

5. Reinsert the puller tool into the valve. Maneuver the puller tool inside the valve in order to grasp the spring. Withdraw the spring from the valve.

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Illustration 6	g01190527

6. Carefully place the end of the gauge into the valve opening.

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Illustration 7	g01190528

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Illustration 8	g01190607

7. Use a slight twisting motion and downward pressure as you attempt to insert the gauge fully. The gauge is inserted fully when the gauge is inserted to the groove that is provided on the gauge.

Rework Guidelines

1. If the gauge can not be inserted fully, replace the complete valve stack.

2. If the gauge can be inserted fully, replace the original spool with a 278-9570 Spool . Reuse the original spring.

   Note: You can replace a maximum of two spools on "air conditioned" machines or you can replace a maximum of three spools on "non-air conditioned" machines.

3. When an "air conditioned" machine has a total of three or more failed functions and the gauge fits into all of the bores, replace the complete valve stack that has the most failed functions.

4. When a "non-air conditioned" machine has a total of four or more failed functions and the gauge fits into all of the bores, replace the complete valve stack that has the most failed functions.

Rework Options

Replacing the Spool

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Illustration 9	g01190529

1. Insert the spring that was previously removed into the valve.

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Illustration 10	g01190531

2. Carefully insert the 278-9570 Spool into the valve.

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Illustration 11	g01190525

3. Exert downward force in order to seat the spool fully in the valve.

   Note: As you seat the spool, ensure that the bottom of the spool surrounds the top portion of the spring. Refer to Illustration 14.

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Illustration 12	g01190556

4. Check the condition of the 2M-9780 O-Ring Seal that is installed on the plug. Replace the O-ring seal, if necessary.

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Illustration 13	g01190767

5. Reinstall the plug. Tighten the plug to a torque of 70 ± 7 N·m (50 ± 5 lb ft).

Replacing the Complete Valve Stack

If replacement of the complete valve stack is necessary, perform the removal procedure and the installation procedure that is provided in the Disassembly and Assembly Manual for your machine.

Appendix

Illustration 14	g01190844
Section view of the flow control valve (W) Plug (X) O-ring Seal (Y) Spool (Z) Spring