Field Installation of the Hystat Joystick Effort and Modulation Springs{5059} Caterpillar

Track-Type Tractors:

D3C Series III (PIN: 4KS1-431; 4TS1-394; 5GS1-297)

D4C Series III (PIN: 4LS1-270; 6BS1-341; 8CS1-510)

D5C Series III (PIN: 5HS1-386; 6CS1-384; 7PS1-561)

Introduction

This instruction provides information about the required parts and the procedure to install recalibrated modulation springs and effort springs for the Hystat pilot control valve (joystick) for the transmission. Recalibrated modulation springs will modify system response. The effort springs will slightly increase the pressure required to deflect the handle forward and reverse. These improvements will improve the control of the machine over rough terrain.

The recalibrated modulation springs will be placed in four positions of the pilot valve. Effort springs will only be used for forward and reverse.

The shaft for the control handle will also be replaced. The new shaft tilts the control handle toward the operator fifteen degrees. The new angle of the control handle provides the operator with a more comfortable operating position.

Note: Handle the pilot valve kits with care. The pilot valve assemblies could easily come apart. The parts could be misplaced.

Reference: Operation and Maintenance Manual, SEBU7077

The information in this instruction should be read and understood before proceeding with any modifications.

Read the following safety information which is provided in the appropriate Operation and Maintenance Manual: General Hazard Information, Crushing Prevention and Cutting Prevention, Burn Prevention, Fire Prevention and Explosion Prevention and Machine Parking.

Required Parts

Preparation for Installation

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Illustration 1	g00457123

1. Remove the 117-5804 Cover (1). Remove the 5G-1673 Cover (2). See Illustration 1.

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Illustration 2	g00457143
Roll pin (14) .

2. Remove boot (3) from the top of the valve body. Fold boot (3) in order to access the components below. See Illustration 2.

3. Locate harness connection (4) below the valve body. Disconnect the DT connector.

4. Remove the pins from the DT connector. The parts from the DT connector will be used during assembly.

5. Carefully pull harness (5) through the valve body (6) and plunger plate (7) .

6. Loosen jam nut (8).

7. Unscrew shaft (9) in order to remove the following items: control handle (10), boot (3) and jam nut (8) .

8. Remove coupler (11) .

9. Remove actuator (12) for the plungers .

10. Insert a screwdriver with a flat blade into U-joint (13). Unscrew U-joint (13). Remove U-joint (13) from the valve body.

11. Remove plunger plate (7) .

Location of Valves in Valve Body

Illustration 3	g00468835

Removal of the Steering Pilot Valve Kit and Installation of the 159-4747 Pilot Valve Kits (Steering)

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Illustration 4	g00469207

Note: Complete the disassembly and assembly of one pilot valve before proceeding to the next valve.

1. Insert two standard screwdrivers under opposite sides of plunger guide (1). Carefully pry plunger guide (1). Remove plunger guide (1) from the valve body (2). See Illustration 4.

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Illustration 5	g00457145
Plunger (3). Spring (4) .

2. Remove the following items: plunger assembly (A) and spool assembly (B). Spring (6) does not need to be removed. See Illustration 5.

3. Remove any contamination from valve body (7) .

4. Use the oil from the machine hydraulic system in order to coat each part before assembly.

Note: Handle the plunger assemblies with care. The plunger assemblies of the pilot valve kits could easily come apart. The parts could be misplaced.

5. The 159-4747 Pilot Valve Kit (Steering) consists of one plunger assembly (A) and one spool assembly (B). Install one new spool assembly (B) into valve body (7). See Illustration 5.

6. Use one 0.5 mm (0.02 inch) shim (5) for plunger assembly (A). Discard the extra shims. Install plunger assembly (A) into valve body (7) .

7. Push plunger (3) and plunger guide (9) into the valve body (7) .

8. Repeat steps 1 through 7 in order to install the second 159-4747 Pilot Valve Kit (Steering) into valve body (7) .

Removal of the Forward and Reverse Pilot Valve Kit and Installation of the 159-4746 Pilot Valve Kits (Forward and Reverse)

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Illustration 6	g00457144

1. Insert two standard screwdrivers under opposite sides of plunger guide (1). Carefully pry plunger guide (1). Remove plunger guide (1) from the valve body (2). See Illustration 6.

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Illustration 7	g00471269
Plunger (3) .

2. Remove the following parts from one forward and reverse valve only: plunger assembly (A) and spool assembly (B). See Illustration 4 for the location of the valve.

3. Remove any contamination from valve body (7) .

4. Use the oil from the machine hydraulic system in order to coat each part before assembly.

   Note: Handle the pilot valve kits with care. The plunger assembly could easily come apart. The parts could be misplaced.

5. Remove one effort spring (6) from valve body (7). Install one spring from the 159-3254 Spring Kit into valve body (7) .

6. The 159-4746 Pilot Valve Kit (Forward and Reverse) consists of one plunger assembly (A) and one spool assembly. Install one new spool assembly (B). See Illustration 7.

7. Use one 0.20 mm (0.008 inch) shim (5) and use one 0.5 mm (0.02 inch) shim (8) for plunger assembly (A). Discard any extra shims. Install plunger assembly (A) into valve body (7) .

8. Push plunger (3) and plunger guide (9) into the valve body (7) .

9. Repeat Steps 1 through 8 in order to install the second 159-4746 Pilot Valve Kit (forward and reverse) into valve body (7) .

Installation of the Control Handle

Illustration 8	g00457143

1. Align the hole for the harness in plunger plate (7) with the hole for the harness in valve body (6). Install plunger plate (7). See Illustration 8.

   Note: Inspect the four plunger guides. The plunger guides must be seated correctly in the valve body.

2. Install U-joint (13). Tighten U-joint (13) to a torque of 30 N·m (22 lb ft).

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Illustration 9	g00467111

3. Install actuator (12) for the plungers.

   1. Ensure contact between plunger (15) and actuator (12). See Position A. Dimension (B) is the gap at the opposite plunger. The size of Dimension (B) is 0.10 ± 0.05 mm (0.004 ± 0.002 inch). See Illustration 9.

      Note: Perform this adjustment for both the steering, and forward and reverse directions.

4. Install coupler (11). Hold actuator (12) while you are tightening coupler (11). Tighten coupler (11) to a torque of 30 N·m (22 lb ft). See Illustration 8.

5. Remove the former boot (3) from the control handle (10). Remove jam nut (8) from shaft (9). See Illustration 8.

6. Remove pin (14) from shaft (9). Remove shaft (9) from the control handle (10). See Illustration 8.

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Illustration 10	g00467554

Note: The 158-3770 Lever Kit contains the following items: a new lever, pin and locknut for the control handle. The new lever will tilt the handle toward the operator. See Illustration 10.

7. The new lever (16) is a slip fit into control handle (10). Align the holes in lever (16) in order to tilt the control handle toward the operator. Install pin (17). Install new jam nut (18) on lever (16). See Illustration 10.

Note: The 158-3769 Boot is also angled.

8. Install the 158-3769 Boot (19) on the control handle. Fold the boot in order to access jam nut (18). Install lever (16) into coupler (11). Tighten jam nut (18) to a torque of 28 N·m (21 lb ft). See Illustration 10.

9. Inspect clearance between actuator (12) and plungers in order to ensure the proper gap. See Illustration 9.

10. Apply grease to the top of the four plungers.

Installation of the Wiring Harness

Illustration 11	g00467616
See Table 3 for the location of the wires.

1. Install harness (5) through valve body (6) and plunger plate (7) .

2. Install the wires in the DT connector. See Illustration 11 and Table 3. Connect the wiring harness.

3. Check the hydraulic oil level. Start the machine. Inspect the valve for hydraulic oil leaks.

4. Install the bottom of the boot on valve body.

5. Test the operation of the pilot control valve (joystick).

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Illustration 12	g00457123

6. Replace the 117-5804 Cover (1). Replace the 5G-1673 Cover (2). See Illustration 12.