784C and 785C Off-Highway Trucks Machine Systems Caterpillar

Removal Procedure

Start By:

1. Release the pressure in the air system. Refer to Disassembly and Assembly, "Air Tanks (Brake) - Purge".

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In order to prevent possible personal injury, release the air pressure from the air tank before disconnecting any components of the air system.

Note: Cleanliness is an important factor. Before the removal procedure, the exterior of the component should be thoroughly cleaned. This will help to prevent dirt from entering the internal mechanism.

Note: Put identification marks on all hose assemblies, on all tube assemblies and on all wire harnesses for installation purposes. Plug all hose assemblies and all tube assemblies. This helps to prevent fluid loss and this helps to prevent contaminants from entering the system.

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Illustration 1	g00498294

1. Disconnect hose assembly (2) from air dryer (1).
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   Illustration 2	g00498295

2. Disconnect hose assembly (3).
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   Illustration 3	g00498296

3. Disconnect hose assembly (4).
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   Illustration 4	g00498298

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   Illustration 5	g00498299

4. Reposition boot (5) and remove two nuts (6). Disconnect wire harness (7).
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   Illustration 6	g00498320

5. Remove four bolts (8) and the washers. Remove air dryer (1) from the frame assembly. Place air dryer (1) on a suitable bench.
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   Illustration 7	g00498321

6. Remove elbows (9), (14), and (12). Remove pipe (15). Remove relief valve (10). Remove two bolts (13), the nuts and washers. Remove two straps (11).

7. For the disassembly and the assembly procedure, refer to Service Manual, SENR7474, "Air Dryer for Vehicle Air Systems", "Air Dryer Disassembly and Assembly" for the correct procedure.

Installation Procedure

Note: Cleanliness is an important factor. Before the installation procedure, all parts should be thoroughly cleaned in cleaning fluid. Allow the parts to air dry. Wiping cloths or rags should not be used to dry parts. Lint may be deposited on the parts which may cause later trouble.

1. Check all of the O-ring seals and the components for wear or damage. Replace the components, if necessary.

2. Lubricate all of the O-ring seals lightly with the lubricant that is being sealed.
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   Illustration 8	g00498321

   Note: Before installation, apply 5P-3413 Pipe Sealant to the external tapered threads.

3. Install two straps (11). Install two bolts (13), the nuts and washers. Install pipe (15). Install relief valve (10). The relief valve should face downward. Install elbows (9), (12) and (14).
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   Illustration 9	g00498320

4. Position air dryer (1) on the frame assembly. Use four bolts (8) and the washers in order to install air dryer (1).
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   Illustration 10	g00498299

5. Connect wire harness (7). Install nut (6) and the washer. Tighten nut (6) to a torque of 2.8 ± 0.6 N·m (24.78 ± 5.31 lb in).
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   Illustration 11	g00498298

6. Reposition boot (5).
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   Illustration 12	g00498296

7. Connect hose assembly (4).
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   Illustration 13	g00498295

8. Connect hose assembly (3).
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   Illustration 14	g00498294

9. Connect hose assembly (2) to air dryer (1).

10. Charge the air pressure in the air tank. Refer to the Operation and Maintenance Manual, SEBU7173, "Starting with an external air supply" for the correct procedure.

End By:

1. Remove the wheel chocks. Refer to Disassembly and Assembly, "Wheel Chock (Front and Rear) - Remove and Install".