Installing a New Alternator Group on Certain Low Altitude 793D Off-Highway Truck Engines{1405, 1408} Caterpillar

Off-Highway Truck:

793D (S/N: FDB1-1828)

Introduction

Do not perform any procedure that is outlined in this Special Instruction until the entire instruction has been read and understood.

This Special Instruction provides the procedure for installing a new alternator group on certain 793D Off-Highway Truck Engines.

Special Instruction, REHS6106, "Procedure to Upgrade the Electrical Wiring Group on Certain 793D Off-Highway Trucks" and Special Instruction, REHS7483, "Installation of the 364-9117 Engine Wiring Gp on 793D Off-Highway Truck Engines" must be completed on S/N:FDB00001-01605 before updating the alternator group.

Note: This alternator upgrade is compatible with any vintage of the 364-9117 Engine Wiring Gp . The latest vintage which contains the 457-9172 Engine Harness As is not required.

Required Parts

Removal

Refer to Disassembly and Assembly, SENR1126, "Alternator - Remove and Install" for more information.

Illustration 1	g03664578

Illustration 2	g03664580

1. Remove the belt guards.

2. Remove the belt.

3. Remove the alternator.

4. Remove the existing positive cable and all associated hardware.

   Note: Some of the existing hardware may be reused.

5. Remove the existing negative cable and all associated hardware.

   Note: Some of the existing hardware may be reused.

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Illustration 3	g03664581

6. Remove the alternator mounting group.

Installation of the Alternator Pulley

Illustration 4	g03664582
(1) 436-6511 Pulley (2) 437-0125 Charging Alternator Gp (3) Conical Washer

1. Install conical washer (3) onto the alternator shaft with the base toward the pulley.

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Illustration 5	g03664583
(2) 437-0125 Charging Alternator Gp (4) 8 mm hex socket

2. Use an 8 mm hex socket (4) to prevent the alternator shaft from turning.

   Torque the nut ... 130 ± 10 N·m (96 ± 7 lb ft)

Wiring Harness Adjustments

Illustration 6	g03682503
Current wiring harness clipping and routing (1) 115-3069 Connector Clip Assembly (2) 7V-6571 Grommet (3) 8T-1889 Clip (4) 8T-1890 Clip

Illustration 7	g03682504
New wiring harness clipping and routing (1) 115-3069 Connector Clip Assembly (2) 7V-6571 Grommet (3) 8T-1889 Clip (4) 8T-1890 Clip (5) 4P-8097 Bracket (6) 0S-1594 Bolt (7) 5M-2894 Hard Washer (8) 9S-8752 Full Nut

1. Remove the original clips (1), (3), and (4) from the clips original location. Set aside associated hardware for reuse.

2. Install clips (3) and (4) on top of the 364-9119 Bracket with the original hardware.

   Note: The original location was under the 364-9119 Bracket and the new location is on top of the 364-9119 Bracket .

3. Attach bracket (5) to the A/C compressor guard with the original hardware.

4. Attach original clip (1) to bracket (5) with one bolt (6), two washers (7), and one nut (8) .

Preliminary Installation of the 462-6449 Cable As (Negative Cable)

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Illustration 8	g03682534
(1) 2H-3855 Bolt (2) 5P-8245 Hard Washer (3) 7V-6571 Grommet (4) 8T-1889 Clip (5) 8T-1890 Clip (6) 0S-1588 Bolt (7) 5M-2894 Hard Washer (8) 9S-8752 Full Nut (9) 4P-8097 Bracket (10) 0L-1351 Bolt (11) 359-1828 Bracket As (12) 0S-1594 Bolt (13) 462-6449 Cable As

1. Attach the end of cable (13) to the engine block with the original bolt (1) and washer (2) .

   Note: Orient the end of the cable in such a way to avoid interference with the cam cover.

2. Attach bracket (9) to the 4P-3485 Bracket with one bolt (10) and one washer (7). Refer to Illustration 8 for the correct orientation of the bracket.

3. Install one grommet (3), one clip (4), and one clip (5) around cable (13) .

4. Attach clips (4) and (5) to bracket (9) with one bolt (6), two washers (7), and one nut (8) .

5. Attach bracket (11) to the 235-0296 Adapter with the original hardware.

6. Install one grommet (3), one clip (4), and one clip (5) around cable (13) .

7. Attach clips (4) and (5) to bracket (11) with one bolt (12) and one washer (7) .

Installation of the Alternator

Note: The 391-3864 Support Assemblies are outfitted with two 209-2086 Dowels that must be removed if being installed on the front housings without holes to receive these dowels. Laser alignment is required for optimal belt performance if the front housing does not have dowel holes.

Illustration 9	g03664584
(1) 391-3864 Support As (2) 0S-1587 Bolt (3) 5P-8245 Hard Washer (4) 374-8497 Belt

1. Attach support assembly (1) snug to the front housing with four bolts (2) and four washers (3) .

   Note: Belt (4) cannot be installed until the alternator pulley has been laser aligned with the drive pulley.

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Illustration 10	g03664624
(1) 391-3864 Support As (5) 1A-5183 Bolt (6) 5M-2894 Hard Washer (7) 437-0125 Charging Alternator Gp (8) 378-0997 Bracket (9) 8F-8544 Bolt

2. Attach alternator (7) and bracket (8) snug to support assembly (1) with two bolts (5), two bolts (9), and four washers (6) .

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Illustration 11	g03682212
Typical two piece laser alignment tool

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Illustration 12	g03682201
(10) Alternator drive pulley (11) Laser alignment tool

Note: Before securing alternator and mounting components, utilize the two piece laser alignment tool from Dayco Belt Diagnostic Kit 93874 to ensure optimal pulley alignment.

3. Attach one piece of the laser alignment tool (11) to alternator pulley (10) and the other piece of the laser alignment tool (11) to the drive pulley.

4. Adjust the 391-3864 Support As as needed to align alternator pulley (10) and the drive pulley.

5. Tighten the bottom two bolts of the 391-3864 Support As .

6. Remove the alternator from the 391-3864 Support As .

7. Tighten the top two bolts of the 391-3864 Support As .

8. Reattach alternator (7) and bracket (8) snug to support assembly (1) as done in Step 2.

9. Recheck the alignment with the two piece laser alignment tool.

10. Adjust (7) and bracket (8) as needed to align alternator pulley (10) and drive pulley. Tighten the bolts.

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Illustration 13	g03664625
(1) 391-3864 Support As (4) 374-8497 Belt (6) 5M-2894 Hard Washer (12) 436-6512 Belt Tensioner (13) 0T-0573 Bolt

11. Install belt (4) onto the drive pulley.

12. Attach belt tensioner (12) to support assembly (1) with one bolt (13) and one washer (6) .

13. Install belt (4) onto the alternator pulley.

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Illustration 14	g03664626
(4) 374-8497 Belt

14. Ensure that belt (4) is properly aligned on both pulleys before installing belt guard.

Installation of the Guard and Completion of the 462-6449 Cable As (Negative Cable) Install

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Illustration 15	g03664628
(1) 434-0773 Guard As (2) 1A-2029 Bolt (3) 198-4766 Hard Washer

1. Attach guard assembly (1) to the 391-3864 Support As and the 378-0997 Bracket with four bolts (2) and four washers (3) .

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Illustration 16	g03682491
(1) 434-0773 Guard As (3) 198-4766 Hard Washer (4) 4P-7581 Clip (5) 0S-1588 Bolt (6) 7K-1181 Cable Strap (7) R+ terminal wire

2. Attach guard assembly (1) and clip (4) to the 391-3864 Support As with one bolt (5) and one washer (3) .

3. Connect the 110-8769 Wire As to the original R+ terminal wire (7) with a 136-4877 Wire Splice . Refer to Special Instruction, REHS7215 for more information.

4. Connect the R+ terminal wire (7) to the alternator. Refer to Illustration 16 for the correct location.

5. Secure the R+ terminal wire (7) to clip (4) with one cable strap (6) .

6. Attach the negative cable to the alternator with the existing alternator hardware.

   Tighten the existing alternator hardware ... 10.8 ± 1 N·m (8 ± 1 lb ft)

Installation of the 461-5754 Cable Assembly (Positive Cable)

Illustration 17	g03682194
(1) 8T-4191 Bolt (2) 8T-4121 Hard Washer (3) 109-3001 Taperlock Stud (4) 344-5675 Nut (5) 7K-1181 Cable Strap (6) 8T-4195 Bolt (7) 6V-0826 Grommet (8) 223-3490 Clip (9) 8T-1889 Clip (10) 8T-1890 Clip (11) 8T-4136 Bolt (12) 461-5754 Cable As (13) 091-9035 Spacer (14) 259-7140 Taperlock Stud

1. Attach cable (12) to the junction block with one bolt (1) and one washer (2) .

2. Secure the boot to cable (12) with one cable strap (5) .

3. Install one grommet (7) and one clip (8) around cable (12). Refer to Illustration 17 for the correct location of the clip.

4. Attach clip (8) and the existing 8T-1889 Clip and 8T-1890 Clip to the truck frame with one stud (3), one washer (2), and one nut (4) .

5. Install one grommet (7), one clip (9), and one clip (10) around cable (12). Refer to Illustration 17 for the correct location of the clip.

6. Attach clips (9) and (10) to the existing 8T-1889 Clip and 8T-1890 Clip with one bolt (6), one washer (2), and one nut (4) .

7. Install one grommet (7), one clip (9), and one clip (10) around cable (12). Refer to Illustration 17 for the correct location of the clip.

8. Attach clips (9) and (10) and the existing 8T-1889 Clip and 8T-1890 Clip to the truck frame with one stud (3), one washer (2), and one nut (4) .

9. Install one grommet (7), one clip (9), and one clip (10) around cable (12). Refer to Illustration 17 for the correct location of the clip.

10. Attach clips (9) and (10) to the truck frame with one bolt (11) and one washer (2)

11. Install one grommet (7) and one clip (8) around cable (12). Refer to Illustration 17 for the correct location of the clip.

12. Attach clip (8) to the truck frame with one stud (3), one washer (2), and one nut (4) .

13. Install one grommet (7) and one clip (8) around cable (12). Refer to Illustration 17 for the correct location of the clip.

14. Attach clip (8) to the truck frame with one spacer (13), one stud (14), one washer (2), and one nut (4) .

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Illustration 18	g03682196
(2) 8T-4121 Hard Washer (4) 344-5675 Nut (7) 6V-0826 Grommet (8) 223-3490 Clip (12) 461-5754 Cable As (14) 259-7140 Taperlock Stud (15) 091-0081 Spacer

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Illustration 19	g03683263
Upper clips (8) 223-3490 Clip

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Illustration 20	g03683265
Lower clip (8) 223-3490 Clip (15) 091-0081 Spacer

15. Install three grommets (7) and three clips (8) around cable (12). Refer to Illustration 18 for the correct location of the clips.

16. Attach the two upper clips (8) to the truck frame with one stud (14), one washer (2), and one nut (4) per clip. Refer to Illustration 19 for the correct orientation of the clips.

17. Attach the one lower clip (8) to the truck frame with one spacer (15), one stud (14), one washer (2), and one nut (4). Refer to Illustration 20 for the correct orientation of the clip.

    Note: The clip is installed on top of the spacer.

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Illustration 21	g03682199
(2) 8T-4121 Hard Washer (4) 344-5675 Nut (5) 7K-1181 Cable Strap (7) 6V-0826 Grommet (9) 8T-1889 Clip (10) 8T-1890 Clip (11) 8T-4136 Bolt (12) 461-5754 Cable As (16) 9L-1566 Support (17) 133-6934 Spacer (18) 8T-8911 Bolt (19) 5P-4116 Hard Washer

18. Install one grommet (7), one clip (9), and one clip (10) around cable (12) .

19. Attach clips (9) and (10) to the truck frame with one bolt (11) and one washer (2) .

20. Install one grommet (7), one clip (9), and one clip (10) around cable (12) .

21. Attach clips (9) and (10) to the 298-6591 Bracket As with one bolt (11) and one washer (2) .

22. Install one grommet (7), one clip (9), and one clip (10) around cable (12) .

23. Attach clips (9) and (10) to the 235-0296 Adapter with one spacer (17), one bolt (18), and one washer (19) .

24. Install one grommet (7), one clip (9), and one clip (10) around cable (12) .

25. Attach clips (9) and (10) to support (16) the with one bolt (11), two washers (2), and one nut (4) .

26. Attach cable (12) to the alternator with the existing alternator hardware.

    Tighten the existing alternator hardware ... 15 ± 1 N·m (11 ± 1 lb ft)

27. Secure the boot to cable (12) with one cable strap (5) .