794 AC Off-Highway Truck Engine Supplement Caterpillar

Removal Procedure

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The Power Train Electric Drive System and the Accessory Power System will contain hazardous voltage levels during machine operation and for a period of time after machine shutdown. Do not remove any covers that will expose energized electrical components while the engine is operating. Do not remove any covers that will expose the energized electrical components while the components remain energized following an engine shutdown. Do not perform any type of electrical maintenance on the orange hazardous voltage conductors, the power train components or the accessory power system components while the engine is operating. Do not perform any type of electrical maintenance on the orange hazardous voltage conductors, the power train components or the accessory power system components while the components remain energized following an engine shutdown. Always perform the safe shutdown and de-energizing procedure before performing electrical service on the Power Train Electric Drive System or the Accessory Power System. Failure to follow these instructions could result in personal injury or death.

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Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.

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Personal injury can result from hot coolant, steam and alkali. At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns. Remove cooling system pressure cap slowly to relieve pressure only when engine is stopped and cooling system pressure cap is cool enough to touch with your bare hand. Do not attempt to tighten hose connections when the coolant is hot, the hose can come off causing burns. Cooling System Coolant Additive contains alkali. Avoid contact with skin and eyes.

1. Prepare the machine for maintenance. Refer to Operation and Maintenance Manual , "Prepare the Machine for Maintenance".

2. Shutdown and de-energizing the machine. Refer to Operation and Maintenance Manual, "Electrical Shutdown and Voltage Discharge".

3. Release the system pressure. Refer to Operation and Maintenance Manual, "System Pressure Release".

4. Drain the coolant to a level below the component being removed. Refer to Operation and Maintenance Manual, "Cooling System Coolant (ELC) - Change" for the correct draining and filling procedure.
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   Illustration 1	g03737673

5. Open hood panels (1).
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   Illustration 2	g03737720

6. Disconnect V-band clamp (2) and tube (3). Loosen clamps (4) and disconnect hose (5).
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   Illustration 3	g03738039

7. Disconnect hose assemblies (6)
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   Illustration 4	g03738046

8. Disconnect V-band clamp (7) and bellows (8). Disconnect V-band clamp (9) and bellows (10).
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   Illustration 5	g03738104

9. Disconnect hose assemblies (11).
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   Illustration 6	g03738138

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   NOTICE
   Do not step on the turbochargers. Doing so can damage the turbocharger and shorten the turbocharger life.

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   NOTICE
   If the turbine housing or the compressor housing must be rotated to remove the turbocharger, loosen the V-band clamp only enough to allow for rotation (typically 7-10 turns). If the V-band clamp is loosened excessively, the housing may contact the turbine wheel or the compressor wheel and cause damage. Contact with the housing may cause rapid wear and shorten turbocharger life.

10. Attach a suitable lifting device to turbocharger (12). The weight of turbocharger (12) is approximately 79 kg (175 lb).

11. Remove bolts (13). Remove turbocharger (12).
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    Illustration 7	g03738151

12. Remove screen assembly (14) and O-ring seal (15).

Installation Procedure

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Illustration 8	g03738151

1. Install O-ring seal (15) and screen assembly (14).

2. Use the following procedure if the turbocharger was loosened for removal
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   Illustration 9	g03738202

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   NOTICE
   Follow the procedure for bellows installation and tightening procedures. Tighten the V-band clamp on the turbine housing prior to the bellows V-band clamp to prevent any dragging or binding of the turbocharger rotating components. Contact may cause rapid wear and shorten turbocharger life.

   1. Apply Tooling (A) onto the stud of V-band clamp (16). Tighten V-band clamp (16) to a torque of 20 N·m (177 lb in). Loosen V-band clamp (16) by two to three turns. Tap lightly with a suitable hammer around the diameter of V-band clamp (16). Tighten V-band clamp (16) to a final torque of 30 ± 2 N·m (266 ± 18 lb in).

   2. If connector (17) was removed, apply Tooling (B) onto the threads of connector (17). Install connector (17).
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   Illustration 10	g03738177

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   Illustration 11	g03738138

3. Ensure turbocharger (12) is aligned with dowel (X) and oil drain fitting (Y). Use a suitable lifting device to install turbocharger (12). The weight of turbocharger (12) is approximately 136 kg (300 lb).

4. Install bolts (13).
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   Illustration 12	g03738104

5. Refill the oil inlet with clean oil. Connect hose assemblies (11).
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   Illustration 13	g03738046

6. Connect V-band clamp (9) and bellows (10). Connect V-band clamp (7) and bellows (8).

7. Tighten V-band clamp (9) to a torque of 10 ± 2 N·m (89 ± 18 lb in). Tighten V-band clamp (7) to a torque of 12 ± 2 N·m (106 ± 18 lb in).

8. Ensure that the compressor wheel spins freely without binding or dragging. Contact with the housing may cause rapid wear and shorten turbocharger life.

9. Refer to Specifications, "Turbocharger".
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   Illustration 14	g03738039

10. Connect hose assemblies (6)
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    Illustration 15	g03737720

11. Connect tube (3) and V-band clamp (2). Tighten V-band clamp (2) to a torque of 9 ± 1 N·m (80 ± 9 lb in). Connect hose (5) and tighten clamps (4) to a torque of 10 ± 2 N·m (89 ± 18 lb in).

    Note: Ensure clamps are positioned at least 110° from each other. Do not position clamps over the bead on the tube. Position the outer clamp approximately 6.35 mm (0.25 inch) from the edge of the hose.

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    Illustration 16	g03737673

12. Close hood panels (1).

13. Refill the engine coolant. Refer to Operation and Maintenance Manual, "Cooling System Coolant (ELC) - Change" for the correct draining and filling procedure.