Improving the Cab Environment for the Operator of Track-Type Tractors{7301, 7304, 7320} Caterpillar

Track-Type Tractor:

D9R (S/N: ABK1-UP; ACL1-UP; 7TL1-UP; 8BL1-UP; WDM1-UP)

D10R (S/N: AKT1-UP; 3KR1-UP)

D11R (S/N: AAF1-UP; 7PZ1-UP; 9TR1-UP; 9XR1-UP)

Introduction

This special instruction provides the procedure to verify that the cab is properly sealed. This special instruction also provides steps in order to help reduce dirt and dust from the cab environment.

System Operation

The air conditioning vent system is a sealed casing. The vent system is designed to recirculate a portion of the air through the recirculating filter. The vent system will also draw a portion of air through the fresh air filter. If either of these filters becomes restricted the cab pressure will be directly affected. Forcing more fresh air into the cab improves cab pressurization. Improved cab pressurization forces the air to exit through any openings in the cab. The improved cab pressurization may also reduce the amount of dust that enters the cab.

Testing Cab Pressure

Required Parts

Testing Procedures

1. Replace the fresh air and recirculation filter elements with new filters.

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Illustration 1	g01279164

2. Plug the low pressure port and the high pressure port on the back of gauge (1) with the plugs that are provided.

3. Assemble the gauge onto the L bracket (4) that is provided.

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Illustration 2	g01279148

4. Lift floor mats and remove one bolt from the floorplate.

5. Close all windows and shut doors tightly.

6. Turn the blower to the OFF position.

7. Place pressure gauge (1) on the dash. Make sure that the gauge is level.

8. Zero gauge (1) by using the screw on the gauge face.

9. By using the barbed fitting that is provided, attach a hose that is approximately 147.32 cm (58 inch) to the low pressure port on the side of gauge (1) .

10. By using the barbed fitting that is provided, attach a hose that is approximately 30.48 cm (12 inch) to either high pressure port on the side of gauge (1) .

11. Route the free end of the low pressure tubing (3) through hole (5) in the floorplate that was created by removing the bolt from the floor.

12. Ensure that no air vents are directed toward the free end of the high pressure tubing (3) .

13. Verify that gauge (1) reads zero.

14. Start the engine.

15. Operate the engine at LOW IDLE.

16. Open all air vents.

17. Turn on the fan speed switch to the HIGH position. Wait in order to stabilize the cab pressure.

18. Read the cab pressure. Make sure that gauge (1) stays level.

    Note: The reading should be greater than 0.05 kPa (0.2 inch of H₂O).

Options for Reducing Dirt and Dust for the Operator

1. In order to improve the cab environment, open all air vents and turn the fan speed switch to the highest setting.

2. Check the fresh air and recirculation filters. Clean the filter or replace the filter, if necessary. Also, clean the surface of the filter seal and the plenum area.

3. Make sure that there is a good seal around the entire perimeter of both filters, so that air is unable to bypass the filter.

4. Ensure that all cover plates, floorplates, and seat plates have good seals. Also, ensure that all hardware is installed. This includes drain plugs.

5. Ensure that implement boots and antenna openings are sealed.

6. Ensure that the grommets for the dash harnesses are in good condition.

7. Check and clean all vents and air ducts.

Options for Improving Cab Pressure

If the cab pressure is low, the following steps can be taken in order to improve pressurization. In order to evaluate the impact of sealing a particular area, you may want to seal the area by a temporary means such as duct tape. Before you use a permanent seal, evaluate the cab pressure again.

Note: Not all options will be valid for all serial number prefixes.

1. Replace worn door seals or damaged door seals.

2. Adjust the cab doors.

   ReferenceFor steps on adjusting the cab doors, refer to Special Instruction, SEHS9177, "Adjustment Procedure for Cab Door Latch Assemblies and Strikers".

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Illustration 3	g01279243
Rear of ripper controls

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Illustration 4	g01279247

3. Remove the sensor and the gasket (6) that is fastened to the ripper control handle. Install 266-8567 cover plate (7) by using 119-0781 Adhesive sealing around all edges.

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Illustration 5	g01279445

4. Reinstall the gasket and the sensor. Apply 4C-4030 Thread Lock Compound and torque bolts (8) to 2.25 N·m (20 lb in).

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Illustration 6	g01279463

5. Seal 148-0334 Split Grommet (9) with 119-0781 Adhesive .

   Note: This grommet is located in front of the right hand operator console. This grommet may be accessed by removing the duct.

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Illustration 7	g01279470

6. Apply 119-0781 Adhesive to the post grommets (10) on the right and left side of the cab.

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Illustration 8	g01279467

7. Apply 119-0781 Adhesive to grommet (11) that is located below the operator's seat in the right rear of the cab.

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Illustration 9	g01292659

8. Install four 091-0079 Plug (12). Apply 5P-3308 Silicone Sealant , as required.