Installation of the Hood Lift Assist Retrofit on Certain Off-Highway Trucks{7251} Caterpillar

Off-Highway Truck:

789C (S/N: 2BW1-UP)

793B (S/N: 1HL1-UP)

793C (S/N: 4AR1-UP; ATY1-UP)

793D (S/N: FDB1-UP)

Introduction

ReferenceSpecial Instruction, REHS1841, "General Welding Procedures"

The following instructions will provide the information needed to install a hood lift assist on the 789C, 793B, 793C (S/N:4AR and ; S/N:ATY), and the 793D. The following list shows the four kits that are available:

• The 367-5104 Hood Kit is used on the 789C and the 793C (4AR)

• The 387-3238 Hood Kit is used on the 793B

• The 379-6967 Hood Kit is used on the 793C (ATY)

• The 367-5264 Hood Kit is used on the 793D

Register the Retrofit

Because retrofits to a prime product will change the configuration of the product, updating the configuration in SIMSi and AIMS is important. If the retrofit information is not provided, Caterpillar will not be able to provide important product updates.

The following information includes instructions on registering the updates and retrofits.

1. When performing a retrofit installation, record the vital information in Table 1.

   Note: If the procedure is performed by the customer, ask the customer to record the proper information.

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   Table 1

   Repair Date
   Product Serial Number
   Service Hours or Service Meter Units
   Removed Component Part Number (1)
   Removed Component Serial Number (1)
   Installed Component Part Number (2)
   Installed Component Serial Number (3)

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   ( 1 )	Only applies if a component is replaced by a retrofit component. If the product is an engine, and the product retrofit is a kit for upgrading the engine, disregard the "Removed Component" information. Refer to detailed instructions in Step 3 for more information.
   ( 2 )	Record the highest level retrofit kit, arrangement, or group part number.
   ( 3 )	Most retrofits will not have a serial number. Exceptions include emissions repower engines and diesel particulate filters.

2. Update the product configuration by entering the information from Table 1 into SIMSi and AIMS.

   Note: For retrofits that have a Caterpillar serial number, the AIMS application is "JIZ111-08". For retrofits that do not have a Caterpillar serial number, the AIMS application is "JIZ111-07".

3. For detailed instructions on updating the product configuration, refer to Special Instruction, REHS5097, "Instructions to Register the Retrofit".

Required Parts

Note: Each kit may have extra pieces of hardware due to package quantities.

Safety

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manuals. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Cat dealer for replacement manuals. Proper care is your responsibility.

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Accidental engine starting can cause injury or death to personnel working on the equipment. To avoid accidental engine starting, disconnect the battery cable from the negative (−) battery terminal. Completely tape all metal surfaces of the disconnected battery cable end in order to prevent contact with other metal surfaces which could activate the engine electrical system. Place a Do Not Operate tag at the Start/Stop switch location to inform personnel that the equipment is being worked on.

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Personal injury or death can result from improper lifting or blocking. When a hoist or jack is used to lift any part or component, stand clear of the area. Be sure the hoist or jack has the correct capacity to lift a component. Install blocks or stands before performance of any work under a heavy component. Approximate weights of the components are shown. Clean all surfaces where parts are to be installed.

Machine Preparation

1. Move the machine to a hard level surface.

2. Avoid sudden steering inputs when you are parking the machine.

3. Apply the service brakes in order to stop the machine.

4. Move the transmission control lever to the PARK position.

5. Raise the body and install the retaining cables. Refer to Operation and Maintenance Manual for instructions on securing the truck body. Place the hoist control lever in the FLOAT position for at least 10 seconds.

6. Turn the engine start switch to the OFF position in order to stop the engine.

7. Turn the battery disconnect switch to the OFF position.

8. Disconnect the battery. Refer to Operation and Maintenance Manual, "Battery or Battery Cable - Inspect/Replace" for additional information disconnecting the battery.

9. Chock the front wheels and the rear wheels. Refer to Disassembly and Assembly, "Wheel Chock (Front and Rear) - Remove and Install".

Weld Specifications

Refer to Special Instruction, REHS1841, "General Welding Procedures" before performing any welding on the machine.

Installation Instructions

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Illustration 1	g02494299
Typical view of the rear handrail assembly

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Illustration 2	g02538677
Typical view of the right side of the cab

1. Remove the hardware that secures the rear handrail assembly at the rear of the hood assembly. Also remove the hardware that secures the latch of the right side of the cab. Remove the rear handrail assembly and the latch. Retain the hardware, the handrail assembly, and the latch.

   Note: The handrail assembly and the latch are removed so that the rear hood assembly can be raised to a full 90 degrees.

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Illustration 3	g02464797
Typical view (A) Front hood assembly (B) Rear hood assembly

3. Raise front hood assembly (A) and rear hood assembly (B) .

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Illustration 4	g02538657
Typical view (B) Rear hood assembly

4. Use the latch to secure front hood assembly (A). Use a suitable device in order to secure rear hood assembly (B) .

Front Hood Assembly

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Illustration 5	g02464798
View of the bottom of front hood assembly (A) (C) 565 ± 5 mm (22.2 ± 0.197 inch) (D) 1820 ± 5 mm (71.6 ± 0.197 inch) (1) 367-3058 Plate As 789C, 793B, 793C (S/N:4AR only), and 793D (1) 367-3064 Plate As 793C (S/N:ATY only)

1. Position two plate assemblies (1) onto the bottom of front hood assembly (A).

   Note: Position the top of plate assemblies (1) against the wall of front hood assembly (A) .

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Illustration 6	g02465336
View of the bottom of front hood assembly (A) (1) 367-3058 Plate As 789C, 793B, 793C (S/N:4AR only), and 793D (1) 367-3064 Plate As 793C (S/N:ATY only)

2. Use two plate assemblies (1) as a pattern and mark the position of the holes in two plate assemblies (1) .

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Illustration 7	g02465356
View of the bottom of front hood assembly (A)

3. Drill 9 mm (0.354 inch) holes through front hood assembly (A) .

   Note: 789C, 793B, 793C (S/N:4AR only), and 793D require 16 total holes.

   Note: 793C (S/N:ATY only) requires 12 total holes.

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Illustration 8	g02494436
Typical view of the top of front hood assembly (A)

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Illustration 9	g02465406
Typical view of the bottom of front hood assembly (A) (1) 367-3058 Plate As 789C, 793B, 793C (S/N:4AR only), and 793D (1) 367-3064 Plate As 793C (S/N:ATY only) (2) 316-8228 Screw (3) 7X-0613 Hard Washer (4) 5C-7261 Nut

4. In order to secure plate assemblies (1) refer to Step 4.a and Step 4.b. Step 4.a is for the 789C, the 793B, the 793C (S/N:4AR only), and the 793D. Step 4.b is for the 793C (S/N:ATY only).

   1. Secure two plate assemblies (1) to the bottom front hood assembly (A) by using 16 screws (2), 32 hard washers (3), and 16 nuts (4). Tighten 16 screws (2) to a torque of 28 ± 7 N·m (248 ± 62 lb in).

   2. Secure two plate assemblies (1) to the bottom front hood assembly (A) by using 12 screws (2), 24 hard washers (3), and 12 nuts (4). Tighten 12 screws (2) to a torque of 28 ± 7 N·m (248 ± 62 lb in).

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Illustration 10	g02465657
View of the bottom of front hood assembly (A) (1) 367-3058 Plate As 789C, 793B,793C (S/N:4AR only), and 793D (1) 367-3064 Plate As 793C (S/N:ATY only)

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Illustration 11	g02465697
Typical view using a level

5. Using a plumb bob or a level, locate the two areas on front hood assembly (A) directly below the center of two plate assemblies (1). Mark the areas.

   Note: Front hood assembly (A) may require tilting forward slightly to allow a plumb bob to hang freely.

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Illustration 12	g02465778
Typical view of the bottom of front hood assembly (A) (5) 367-3055 Plate As

6. Locate two plate assemblies (5) under front hood assembly (A). Locate the center of plate assemblies (5) with the center of the location that was marked in Step 5.

7. Prepare the area under front hood assembly (A) for two plate assemblies (5) for welding. Remove any paint, rust, dirt, debris, or grease for the affected area.

Note: Refer to Special Instruction, REHS1841, "General Welding Procedures" before performing any welding on the machine.

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Illustration 13	g02494458
Typical view of a removed front hood group

Note: If the area that requires welding is not acceptable, the whole front hood group can be removed in order to weld the plate assemblies.

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Illustration 14	g02465837
Typical rear view of the bottom of front hood assembly (A) (W1) 3 mm (0.118 inch) Fillet weld (two places) for the 789C, the 793B, and the 793C (S/N:4AR only) (W1) 2 mm (0.079 inch) Fillet weld (two places) for the 793D and the 793C (S/N:ATY only) (5) 367-3055 Plate As

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Illustration 15	g02465840
Typical front view of the bottom of front hood assembly (A) (W2) 3 mm (0.118 inch) Fillet weld for the 789C, the 793B, and the 793C (S/N:4AR only) (W2) 2 mm (0.079 inch) Fillet weld for the 793D and the 793C (S/N:ATY only) (5) 367-3055 Plate As

8. Weld two plate assemblies (5) to the bottom of front hood assembly (A) .

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Illustration 16	g02466416
Typical view of plate assemblies (5) installed (5) 367-3055 Plate As

9. Paint plate assemblies (5) after all the welding is completed.

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Illustration 17	g02466439
(1) 367-3058 Plate As 789C, 793B, 793C (S/N:4AR only), and 793D (1) 367-3064 Plate As 793C (S/N:ATY only) (5) 367-3055 Plate As (6) 367-3439 Strut As

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NOTICE
Ensure that the correct strut assemblies are being used. Check the part numbers on the strut assemblies before installation.

10. Install two strut assemblies (6) between plate assemblies (1) and plate assemblies (5) .

    Note: Use the cotter and pin that are part of strut assemblies (6) to secure strut assemblies (6) .

    Note: Strut assemblies (6) will need to be compressed approximately 12.7 to 25.4 mm (0.5 to 1 inch) in order for the strut assemblies to align with that holes in the brackets.

Rear Hood Assembly

Note: Step 1 only applies to the 793B, and the 793C (S/N:ATY)

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Illustration 18	g02539117
View of the top of rear hood assembly (B) on the 793C (S/N:ATY) (E) Anti-skid tread

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Illustration 19	g02467763
Typical view of the top of rear hood assembly (B) on the 793C (S/N:ATY) (E) Anti-skid tread

1. After the holes have been drilled in hood assembly (B), trim anti-skid tread (E) so that the washers do not contact the tread.

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Illustration 20	g02467656
Typical view of the bottom of rear hood assembly (B) on the 789C, and the 793C (S/N:4AR only) (F) Wall on the hood assembly (G) 0 mm (0 inch) (7) 367-3064 Plate As

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Illustration 21	g02470059
Typical view of the bottom of rear hood assembly (B) on the 793B and the 793C (S/N:ATY only) (F) Wall on the hood assembly (G) 1247 ± 5 mm (49 ± 0.197 inch) (7) 367-3064 Plate As

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Illustration 22	g02470038
View of the bottom of rear hood assembly (B) on the 793D (F) Wall on the hood assembly (G) 73 ± 5 mm (2.87 ± 0.197 inch) (7) 367-3064 Plate As

2. Position one plate assembly (7) onto the bottom of rear hood assembly (B) .

   Note: Position the top of plate assembly (7) against the wall of rear hood assembly (B) .

   Note: For the 789C, 793B, and the 793C (S/N:4AR only), position the side of plate assembly (7) up to the end of the radius on wall (F)

   Note: Refer to Illustration 20, 22, and 21 for information on each specific machine.

3. Use plate assembly (7) as a pattern, and mark the position of the holes in plate assembly (7) .

4. Drill six 9 mm (0.354 inch) holes through rear hood assembly (B) .

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Illustration 23	g02494618
Typical view of the top of rear hood assembly (B)

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Illustration 24	g02468020
Typical view (2) 316-8228 Screw (3) 7X-0613 Hard Washer (4) 5C-7261 Nut (7) 367-3064 Plate As

5. Secure plate assembly (7) to the bottom of rear hood assembly (B) by using six screws (2), 12 hard washers (3), and six nuts (4). Tighten 6 screws (2) to a torque of 28 ± 7 N·m (248 ± 62 lb in).

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Illustration 25	g02468691
Typical view of the bottom of rear hood assembly (B)

6. Using a plumb bob or a level, locate the area on the beam for the frame directly below the center of plate assembly (7) .

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Illustration 26	g02468716
Typical side view of the frame (H) 55 mm (2.16 inch) for the 789C, 793B, and the 793C (H) 72 mm (2.83 inch) for the 793D (8) 367-3067 Plate As for the 789C, the 793B, and the 793C (8) 367-3061 Plate As for the 793D

7. Locate plate assembly (8) on the frame under rear hood assembly (B). Locate the center of plate assembly (8) with the center of the location that was marked in Step 6.

8. Prepare the area on the frame for plate assembly (8) for welding. Remove any paint, rust, dirt, debris, or grease from the affected area.

Note: Refer to Special Instruction, REHS1841, "General Welding Procedures" before performing any welding on the machine.

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Illustration 27	g02468677
Typical view (W3) 5 mm (0.197 inch) Fillet weld all around (8) 367-3067 Plate As for the 789C, the 793B, and the 793C (8) 367-3061 Plate As for the 793D

9. Weld plate assembly (8) to the frame under rear hood assembly (B) .

10. Paint plate assembly (8) after all the welding is completed.

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Illustration 28	g02729707
Typical view (B) Rear hood assembly (6) 367-3439 Strut As for the, 793B (7) 367-3064 Plate As (8) 367-3067 Plate As for the 789C, 793B, and the 793C (8) 367-3061 Plate As for the 793D (9) 347-4474 Strut As for the 789C, the 793C, and the 793D

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NOTICE
Ensure that the correct strut assembly is being used. Check the part number on the strut assembly before installation.

11. Install strut assembly (6) or strut assembly (9) between plate assembly (7) and plate assembly (8) .

    Note: Use the cotter and pin that are part of the strut assembly to secure the strut assembly.

    Note: Rear hood assembly (B) will be required to be at a 90 degree angle in order to install strut assembly (9) .

    Note: The strut assembly will need to be compressed approximately 12.7 to 25.4 mm (0.5 to 1 inch) in order for the strut assembly to align with that hole in the bracket.

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Illustration 29	g02494780
Typical view of the rear handrail assembly

12. Install the previously removed rear handrail assembly with the hardware that was previously removed.