Installation of Final Drive Seal Guards{7172} Caterpillar

Introduction

This Special Instruction provides the necessary procedure for installing final drive seal guards on D8N, D9N, and D10N Tractors. The seal guard design has a secondary seal to prevent debris from entering the Duo-Cone seal area. The close fit and tolerances limit the size of the debris that can enter the labyrinth to 2 mm (.08 in). The labyrinth changes the direction of the debris four times before it contacts the secondary seal. This reduces the damage caused by the ability to pack debris and string like material into the final drive Duo-Cone seal area.

The cavity between this secondary seal and the Duo-Cone seal is filled with a lithium type multipurpose grease. The cavity can be flushed to remove any contaminants which have passed by the secondary seal. Grease is pumped into the cavity between the secondary seal and Duo-Cone seals at installation. The grease fitting and vent hole are then plugged. The grease becomes a barrier to water, mud, and debris.

The secondary seal can be replaced at the normal maintenance period, without removing the final drive. The secondary seal is held in place by a captive flange that can be removed. This allows the replacement of the secondary seal without removing the final drive. The secondary seal has a split that allows the seal to be placed over the spindle.

After the assembly is complete, prepare the machine for service as shown in the machine's Operation & Maintenance Manual.

Do not perform any procedure, outlined in this publication, or order any parts until you read and understand the information contained within.

Reference: Disassembly and Assembly Service Manual module, Parts Manual, Operation & Maintenance Manual, and Special Instruction SEHS8364; "Assembly and Installation of Conventional Duo-Cone Seals".

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

Installation Procedure

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Sudden movement of the machine can cause injury to persons on or near the machine. To prevent possible injury, do the procedure that follows before working on the machine.

* Permit only one operator on the machine. Keep all other personnel away from machine or in view of the operator.

* Move the machine to a hard, level surface. Move away from working machines and personnel.

* Engage the parking brake.

* Stop the engine.

Necessary Parts

Disassembly Procedure (All Models)

NOTE: Refer to the Disassembly and Assembly Service Manual module for your machine to remove the final drives.

1. Remove the final drives from the machine.

2. Disassemble the final drives.

3. Remove the original guards from the spindle and sprocket hubs (see the modification procedures).

D8N Modification Procedure

(H) 7T8001 Hub (part of 1Q2257 Spindle).

Machine hub (H) to dimensions shown in Chart 1.

NOTE: If hub (H) has been modified, it is necessary to machine or air-arc off the former guard.

(U) 9W3374 Hub (part of 1Q2258 Sprocket Hub).

Machine hub (U) to dimensions shown in Chart 2.

NOTE: If hub (U) has not been modified, additional machining is required (prior machining does not affect this installation).

D8N Assembly Procedure

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Do not flame cut or weld on painted areas. The effect of gasses from burned paint is a danger to the person doing the cutting or welding.

1. Heat sprocket hub guard (2) to a minimum of 121°C (250°F) before pressing into position on sprocket hub (BB).

2. Press sprocket hub guard (2) into position on sprocket hub (BB).

NOTE: Do not weld sprocket hub guard (2) to sprocket hub.

3. Place retainer (3) over spindle (AA).

NOTE: Step 3 must be done before spindle guard (1) is pressed into position on spindle (AA).

4. Heat spindle guard (1) to a minimum of 121°C (250°F) before pressing into position on spindle (AA).

5. Preheat spindle (AA) to 121°C (250°F). Weld at area (DD) all around spindle (AA) with a 5 mm (.2 in) v-groove weld.

6. Assemble the final drive. Refer to the Disassembly and Assembly Service Manual module for assembly of the final drive.

7. Assemble seal (4) (with multipurpose lithium grease on the lip of the seal) to sprocket hub guard (2) and spindle guard (1).

NOTE: Seal (4) must be positioned with the split in the 12 o'clock position, as seen with the final drive installed.

8. Apply 7M7260 Liquid Gasket to the mating surfaces of sprocket hub guard (2) and retainer (3).

9. Assemble retainer (3) to sprocket hub guard (2) with 12 washers (5) and 12 bolts (6). Use 2P2506 Anti-seize Compound on bolt threads.

NOTE: Clearance at (CC) should be 2.00 mm (.079 in).

10. Install fitting (grease) (8) into either vent hole in sprocket hub guard (2).

11. Fill (slowly to prevent Duo-Cone seal displacement) with 2P9066 Multipurpose Lithium Grease until the grease comes out the open (second) vent hole.

12. Remove fitting (grease) (8). Install two plugs (7) to sprocket hub guard (2).

13. Repeat the assembly procedure for the other final drive.

D9N Modification Procedure

(F) 7T3690 Hub (part of 1Q2255 Spindle).

Machine hub (F) to dimensions shown in Chart 3.

NOTE: If hub (F) has been modified, it is necessary to machine or air-arc off the former guard.

(T) 7T3691 Hub (part of 1Q2256 Sprocket Hub).

Machine hub (T) to dimensions shown in Chart 4.

NOTE: If hub (T) has not been modified, additional machining is required (prior machining does not affect this installation).

D9N Assembly Procedure

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Do not flame cut or weld on painted areas. The effect of gasses from burned paint is a danger to the person doing the cutting or welding.

1. Heat spindle guard (1) to a minimum of 121°C (250°F) before pressing into position on spindle (AA).

2. Press spindle guard (1) into position on spindle (AA).

3. Preheat spindle (AA) to 121°C (250°F). Weld at area (DD) all around spindle (AA) with a 5 mm (.2 in) v-groove weld.

4. Place retainer (3) over sprocket hub (BB).

NOTE: Step 4 must be done before sprocket hub guard (2) is pressed into position on sprocket hub (BB).

5. Heat sprocket hub guard (2) to a minimum of 121°C (250°F) before pressing into position on sprocket hub (BB).

NOTE: Do not weld sprocket hub guard (2) to sprocket hub (BB).

6. Assemble the final drive. Refer to the Disassembly and Assembly Service Manual module for assembly of the final drive.

7. Assemble seal (4) (with multipurpose lithium grease on the lip of the seal) to spindle guard (1) and sprocket hub guard (2).

NOTE: Seal (4) must be positioned with the split in the 12 o'clock position, as seen with the final drive installed.

8. Apply 7M7260 Liquid Gasket to the mating surfaces of spindle guard (1) and retainer (3).

9. Assemble retainer (3) to spindle guard (1) with 16 washers (5) and 16 bolts (6). Use 2P2506 Anti-seize Compound on bolt threads.

NOTE: Clearance at (CC) should be 2.00 mm (.079 in).

10. Install fitting (grease) (8) into either vent hole in sprocket hub guard (2).

11. Fill (slowly to prevent Duo-Cone seal displacement) with 2P9066 Multipurpose Lithium Grease until the grease comes out the open (second) vent hole.

12. Remove fitting (grease) (8). Install two plugs (7) to spindle guard (1).

13. Repeat the assembly procedure for other final drive.

D10N Modification Procedure

(F) 7T5483 Hub (part of 1Q2371 Spindle).

Machine hub (F) to dimensions shown in Chart 5.

NOTE: If hub (F) has been modified, it is necessary to machine or air-arc off the former guard.

(T) 7T5484 Hub (part of 1Q2369 Sprocket Hub).

Machine hub (T) to dimensions shown in Chart 6.

NOTE: If hub (T) has not been modified, additional machining is required (prior machining does not affect this installation).

D10N Assembly Procedure

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Do not flame cut or weld on painted areas. The effect of gasses from burned paint is a danger to the person doing the cutting or welding.

1. Heat spindle guard (1) to a minimum of 121°C (250°F) before pressing into position on spindle (AA).

2. Press spindle guard (1) into position on spindle (AA).

3. Preheat spindle (AA) to 121°C (250°F). Weld at area (DD) all around spindle (AA) with a 5 mm (.2 in) v-groove weld.

4. Place retainer (3) over sprocket hub (BB).

NOTE: Step 4 must be done before sprocket hub guard (2) is pressed into position on sprocket hub (BB).

5. Heat sprocket hub guard (2) to a minimum of 121°C (250°F) before pressing into position on sprocket hub (BB).

NOTE: Do not weld sprocket hub guard (2) to sprocket hub (BB).

6. Assemble the final drive. Refer to the Disassembly and Assembly Service Manual module for assembly of the final drive.

7. Assemble seal (4) (with multipurpose lithium grease on the lip of the seal) to spindle guard (1) and sprocket hub guard (2).

NOTE: Seal (4) must be positioned with the split in the 12 o'clock position, as seen with the final drive installed.

8. Apply 7M7260 Liquid Gasket to the mating surfaces of spindle guard (1) and retainer (3).

9. Assemble retainer (3) to spindle guard (1) with 16 washers (5) and 16 bolts (6). Use 2P2506 Anti-seize Compound on bolt threads.

NOTE: Clearance at (CC) should be 2.00 mm (.079 in).

10. Install fitting (grease) (8) into either vent hole in sprocket hub guard (2).

11. Fill (slowly to prevent Duo-Cone seal displacement) with 2P9066 Multipurpose Lithium Grease until the grease comes out the open (second) vent hole.

12. Remove fitting (grease) (8). Install two plugs (7) to spindle guard (1).

13. Repeat the assembly procedure for other final drive.