A Procedure to Remove the Check Valve on Certain Field Installed Quick Coupler Lines Groups{5057, 6129, 7000} Caterpillar

Work Tool:

QUICK COUPLER (S/N: ANA1-UP; BBA1-UP; B9A1-UP; MBA1-UP; MKA1-UP; PGA1-UP; XCA1-UP; XXA1-UP; MKB1-UP; PGB1-UP; XXB1-UP; PGC1-UP; XXC1-UP; APD1-UP; PGD1-UP; XXD1-UP; BAF1-UP; PGF1-UP; ANH1-UP; APK1-UP; BTP1-UP; BAT1-UP; 7SW1-UP; PBX1-UP; BBZ1-UP)

Introduction

This special instruction describes the removal of the 123-4750 Check Valve . The check valve is replaced by a 6V-8636 Connector . This procedure is designed to correct a problem with a leaking hydraulic line on certain field installed hydraulic lines groups. The hydraulic lines are used with hydraulic pin grabber quick couplers. There are several reports of the 176-0344 Hose As leaking or coming apart at crimped fittings. Removal of the check valve will eliminate the problem of the leak from the hose. A study of this problem indicated that this check valve is redundant. Removal of this check valve will have no effect on retention capability of the hydraulic pin grabber quick coupler.

Reference

ReferenceSpecial Instruction, REHS0745, "Installation of 169-9513 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS0746, "Installation of 177-1400 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS0747, "Installation of 177-1401 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS1574, "Installation of 200-4106 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS1373, "Installation of 225-3742 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS1357, "Installation of 224-3980 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS1390, "Installation of 226-2409 Coupler Lines Gp "

ReferenceSpecial Instruction, REHS3064, "Installation of 283-2554 Coupler Lines Gp "

Required Parts

Do not perform any procedure that is outlined in this publication and do not order any parts until you understand the information that is contained in this document.

Required Tools

Procedure for Removing the Check Valve

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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.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

1. Release the hydraulic system pressure. Refer to the host machine Disassembly and Assembly, "Hydraulic System Pressure - Release".

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Illustration 1	g01247232
Vacuum cap

2. Remove the cap from the hydraulic tank and install Tooling (A). Attach an air supply hose onto Tooling (A). Apply 345 ± 69 kPa (50 ± 10 psi). This procedure will pull vacuum on the hydraulic system.

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Illustration 2	g00737239
This illustration shows the mounting location for the control valve on the following models: 320B, 320C, 322B, 322C, 325B, 325C, 330B and 330C. The location of the control valve may vary depending on the machine type and size.

3. Locate the 170-2470 Solenoid Valve and Mounting Gp in the hydraulic compartment of the host machine.

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Illustration 3	g01366898
Location of the 176-0344 Hose As on a 320B

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Illustration 4	g01366903
Location of the 123-4750 Check Valve on a 320B

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Illustration 5	g01366906
Location of the 123-4750 Check Valve on a 330B (The check valve and hydraulic line are not shown)

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Illustration 6	g01366911
Location of the 123-4750 Check Valve on C-series excavators

4. Follow the 176-0344 Hose As from the valve to the pump. The location of the 123-4750 Check Valve is between the hose and the elbow fitting.

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Illustration 7	g01366914
(1) 176-0344 Hose As (2) 123-4750 Check Valve (3) Adapter

5. Disconnect the hose assembly (1) from the check valve (2) .

6. Remove the check valve (2) from the adapter (3) .

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Illustration 8	g01366915
(1) 176-0344 Hose As (3) Adapter (4) 6V-8636 Connector (5) 3J-1907 O-Ring Seal (6) 6V-8397 O-Ring Seal

7. Install a connector (4) with a new O-ring seal (5) and a new O-ring seal (6) to the adapter (3) .

8. Assemble the hose assembly (1) to the connector (4) .

9. Remove tooling (A) .

10. Start the engine of the host machine. Adjust the engine to low idle.

11. Operate the quick coupler.

12. Inspect the hydraulic lines for leaks.