Adjustment and Modification Procedures to Alleviate Track Jumping/Indexing Caterpillar

Track-Type Tractor:

D6R (S/N: 1RW1-UP; 2HM1-UP; 2YN1-UP; 3ZN1-UP; 4FM1-UP; 4HN1-UP; 4JR1-UP; 4MN1-UP; 4TR1-UP; 4WR1-UP; 5LN1-UP; 5PR1-UP; 5RR1-UP; 6FR1-UP; 6GR1-UP; 6HR1-UP; 6JN1-UP; 6MR1-UP; 7AR1-UP; 7DR1-UP; 7GR1-UP; 7KN1-UP; 8LN1-UP; 8TM1-UP; 8XN1-UP; 9BM1-UP; 9MN1-UP; 9PN1-UP)

Introduction

This special instruction provides an adjustment procedure and a modification procedure to increase the preload on the recoil spring in order to help prevent track jumping. Illustrations, specifications, and procedures are included.

Safety

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Do not attempt to assemble this machine until you read and you understand the assembly instructions. Improper assembly procedures could result in injury or death.

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Accidental engine starting can cause injury or death to personnel working on the equipment. 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.

Note: Do the adjustment procedure first. Then, do the modification to the spacer plate, if necessary.

Adjustment Procedure

Procedure to Purge Air From the System

Note: Use 30W power train oil for the following procedure.

1. Pump the recoil cylinders until the cylinders are fully extended.

2. Then, fully compress each recoil cylinder.

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NOTICE
For machines with the "XL" configuration, care must be taken in order to avoid damage to the idler mounting block and caps. The idler mounting block and caps can hit the front track guiding guards when the assembly is retracted too far back into the rear track roller frame.

3. Use the following method to compress the cylinders. Place a block of wood in front of the track. Drive into the block of wood until the cylinder is fully compressed. While the cylinder is fully compressed, tighten the relief valve. Then, use 30W power train oil to pump the recoil cylinders until the cylinders are fully extended.

4. Extend and compress each cylinder four times in order to ensure that no air is present in the system.

5. Adjust the track normally.

Modification to the Spacer Plate for the Recoil Spring

Note: This procedure is for adding a plate to the existing plate on the end of the tube in the recoil spring assembly in order to increase the preload on the spring.

1. Remove the recoil spring assembly.

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Illustration 1	g00796050
(1) Thickness of the fabricated plate 10 mm (0.39 inch) (2) Fabricated plate (3) Original plate assembly (4) Notches are 15 to 20 mm (0.59 to 0.79 inch) deep from the outside diameter of the fabricated plate. (5) Outside diameter of the fabricated plate 205 mm (8.08 inch)

2. Use the original plate assembly as a template to fabricate spacer plate (2). Use the dimensions that are shown in Illustration 1.

   Note: The thickness of the fabricated plate must not exceed 10 mm (0.39 inch).

3. Cut or burn four notches in plate (2). Use the dimensions that are given in Illustration 1.

4. Align the notches in fabricated plate (2) with the oil holes in plate assembly (3) .

5. In order to prevent plate (2) from shifting and blocking the oil flow, tack weld plate (2) in place on plate assembly (3) .

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NOTICE
Follow all of the safety procedures typical of recoil spring installation. Refer to the D&A Manual for the Power Train, "Recoil Spring", for the proper procedures. This module is located in the Service Manual for your machine.

6. Reinstall the recoil spring assembly.

7. After this modification is completed, do the procedure to purge the air from the system.

8. Adjust the track normally.