Installation Instructions For The New Solid-State Main Power Relay On Certain D6T Track-Type Tractors {1422, 1426} Caterpillar

Track-Type Tractor

D6T (S/N: 2D21-111; CR31-UP; 2B31-231; MB51-305; AK71-110; MH71-745; CG81-UP; 7C91-135; SGA1-UP; KSB1-UP; ZJB1-UP; JZC1-UP; DTD1-UP; RAD1-UP; STE1-UP; EJJ1-UP; SLJ1-UP; GMK1-UP; RRK1-UP; JML1-458; MEL1-UP; JNM1-462; TSM1-UP; WLM1-UP; WRN1-UP; K1R1-176; KMR1-UP; PLR1-UP; WES1-UP; HYT1-367; SGT1-UP; JRW1-UP; RCW1-UP; NDY1-405; TMY1-UP; HTZ1-UP; SGZ1-463)

Introduction

This Special Instruction contains the information to install a new solid-state main power relay on certain D6T Track-Type Tractors. The new solid-state main power relay improves reliability during extreme cold weather. Do not perform any procedure in this Special Instruction until you have read and understood the information.

The affected serial numbers are subdivided into four groups. The groups are identified by the number of bolts used to assemble the pass-through of the positive battery cable to the main relay and the completion of a service letter that provided a temporary solution, and the current mounting provisions.

Group 1 consists of machines that were manufactured with a 2 bolt pass-through and did not have the service letter performed.

Group 2 consists of machines that were manufactured with a 4 bolt pass-through. A service letter was performed on a small population of these machines. Regardless if the service letter was performed or was not performed, the instructions in this special instruction and the new parts listed in this document must be used.

Group 3 consists of machines that were manufactured with a 2 bolt pass-through and that also had the previous service letter performed.

Group 4 consists of machines that were manufactured with the proper mounting holes for the solid-state relay, but were not equipped with the SSR from the factory.

Safety Section

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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 Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Caterpillar dealer for replacement manuals. Proper care is your responsibility.

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Personal injury or death can result from improper assembly procedures. Do not attempt any assembly until you have read and understand the assembly instructions.

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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.

Required Parts

Installation Procedure For Group 1 Machines

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Illustration 1	g06142059

1. Locate the main power relay on the left-hand fender of the tractor.

   1. Turn main battery disconnect switch (A) to the OFF position.

   2. Open battery access cover (B).

   3. Remove the front battery cover by removing the 5 bolts and 5 washers from location (C) that hold the cover in place. Retain the bolts and washers for reassembly.
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   Illustration 2	g06143521

2. Remove bus bar (D), red cable (E), purple cable (F), and the relay (G). The parts and hardware may be discarded.
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   Illustration 3	g06143829
   (7) 7Y-7389 Screw (9) 9X-2040 Screw (11) 9X-8256 Washer (17) 515-2470 Plate As

3. Assemble new relay assembly mounting plate (17) using the hardware that is shown in Illustration 3.
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   Illustration 4	g06143889
   (10) 9X-2046 Screw (16) 542-3264 Relay

4. Assemble relay (16) onto the mounting plate using screws (10). Only hand tighten the screws now.
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   Illustration 5	g06144230
   (H) 2 Bolt pass-through (2) 3S-2093 Cable Strap (3) 4B-4277 Washer (4) 5C-7261 Nut (5) 6V-8801 Nut (6) 7X-0608 Hard Washer (8) 8Q-6744 Mounting Base (12) 480-0089 Wiring Harness (13) 484-8950 Cable As (Purple) (14) 484-8951 Cable As (Red) (15) 490-4245 Washer (Belleville) (18) 515-2471 Bus Bar (Strap)

5. Assemble the new parts using the hardware that is shown in Illustration 5.

   1. First, assemble bus bar (18) onto the 2 bolt pass-through at location (H).

   2. Next, assemble the 90˚ end of (red) cable assembly (14) onto the 2 bolt pass-through at location (H).

   3. Secure the cable assembly by using washer (6) and nut (5). Verify that the hardware stack-up matches the detail view in Illustration 5. Torque the nut to 15 ± 3 N·m (133 ± 27 lb in).

   4. Assemble jumper wire (12) between the relay and the existing wire harness.

   5. Secure the jumper with adhesive backed mounting bases (8) and cable straps (2) as indicated in Illustration 5.

      Note: Make sure that the surface is clean before installing mounting bases (8).

   6. Assemble the other end of bus bar (18) and the appropriate end of (purple) cable assembly (13) onto relay (16) by using washers (3), Belleville washers (15), and nuts (4). Verify that the hardware stack-up matches the detail view in Illustration 5. Torque the nuts to 15 ± 3 N·m (133 ± 27 lb in).

   7. Last, torque relay mounting screws (10) to 12 ± 3 N·m (106 ± 27 lb in).
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   Illustration 6	g06145534
   (1) 3F-9556 Lockwasher (3) 4B-4277 Washer (4) 5C-7261 Nut (13) 484-8950 Cable As (Purple) (14) 484-8951 Cable As (Red)

6. Assemble the ends of the (red) cable assembly (14) and the (purple) cable assembly (13) onto the studs at the bottom of the fuse block as shown in the detail view in Illustration 6. Torque the nuts to 19 ± 1 N·m (168 ± 9 lb in).

7. Turn main battery disconnect switch to the ON position and verify that the system is operating properly.

8. When correct system operation has been verified, apply Caterpillar approved spray paint to the relay stud joints to prevent corrosion.

9. Reassemble the front battery cover using the bolts and washers that were removed in step 1c.

Installation Procedure For Group 2 Machines

Group 2 consists of machines that were manufactured with a 4 bolt pass-through. The service letter was performed on a small population of these machines. Regardless if the service letter was performed or was not performed, the instructions in this special instruction and the new parts listed in this document must be used.

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Illustration 7	g06142059

1. Locate the main power relay on the left-hand fender of the tractor.

   1. Turn main battery disconnect switch (A) to the OFF position.

   2. Open battery access cover (B).

   3. Remove the front battery cover by removing the 5 bolts and 5 washers from location (C) that hold the cover in place. Retain the bolts and washers for reassembly.
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   Illustration 8	g06146848

2. Remove bus bars (D), (E), (F), and the relay (G). The parts and hardware may be discarded.

   If the service letter was previously completed on your machine, remove all the components between the pass-through and the studs at the bottom of the fuse block. The relay mounting bracket must also be replaced. The parts may be discarded.

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   Illustration 9	g06147169
   (6) 7Y-7389 Screw (9) 9X-2040 Screw (11) 9X-8256 Washer (17) 515-2470 Plate As

3. Assemble new relay assembly mounting plate (17) using the hardware that is shown in Illustration 9.
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   Illustration 10	g06143889
   (10) 9X-2046 Screw (16) 542-3264 Relay

4. Assemble relay (16) onto the mounting plate using screws (10). Only hand tighten the screws now.
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   Illustration 11	g06147207
   (H) 4 Bolt pass-through (5) 7X-0584 Hard Washer (8) 8T-4179 Bolt (10) 9X-2046 Screw (15) 484-8951 Cable As (Red) (16) 542-3264 Relay (18) 515-2472 Bus Bar (Strap)

5. Assemble the new parts using the hardware that is shown in Illustration 11.

   1. First, assemble bus bar (18) onto the pass through and relay.

   2. Next, assemble the 90˚ end of (red) cable assembly (15) onto the 4 bolt pass-through at location (H).

   3. Secure the cable assembly and the bus bar by using washer (5) and bolt (8). Torque the bolt to 40 ± 9 N·m (354 ± 80 lb in).
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   Illustration 12	g06147386
   (2) 3S-2093 Cable Strap (3) 4B-4277 Washer (4) 5C-7261 Nut (7) 8Q-6744 Mounting Base (12) 480-0089 Wiring Harness (13) 484-8950 Cable As (Purple) (14) 490-4245 Washer (Belleville) (18) 515-2472 Bus Bar (Strap)

6. Assemble the new parts using the hardware that is shown in Illustration 12.

   1. Assemble jumper wire (12) between the relay and the existing wire harness.

   2. Secure the jumper with adhesive backed mounting bases (7) and cable straps (2) as indicated in Illustration 12.

      Note: Make sure that the surface is clean before installing mounting bases (7).

   3. Assemble the other end of bus bar (18) and the appropriate end of (purple) cable assembly (13) onto relay (16) by using washers (3), Belleville washers (14), and nuts (4). Verify that the hardware stack-up matches the detail view in Illustration 12. Torque the nuts to 15 ± 3 N·m (133 ± 27 lb in).

   4. Last, torque relay mounting screws (10) to 12 ± 3 N·m (106 ± 27 lb in).
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   Illustration 13	g06156660
   (1) 3F-9556 Lockwasher (3) 4B-4277 Washer (4) 5C-7261 Nut (13) 484-8950 Cable As (Purple) (15) 484-8951 Cable As (Red)

7. Assemble the ends of the (red) cable assembly (15) and the (purple) cable assembly (13) onto the studs at the bottom of the fuse block as shown in the detail view in Illustration 13. Torque the nuts to 19 ± 1 N·m (168 ± 9 lb in).

8. Turn main battery disconnect switch to the ON position and verify that the system is operating properly.

9. When correct system operation has been verified, apply Caterpillar approved spray paint to the relay stud joints to prevent corrosion.

10. Reassemble the front battery cover using the bolts and washers that were removed in step 1c.

Installation Procedure For Group 3 Machines

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Illustration 14	g06142059

1. Locate the main power relay on the left-hand fender of the tractor.

   1. Turn main battery disconnect switch (A) to the OFF position.

   2. Open battery access cover (B).

   3. Remove the front battery cover by removing the 5 bolts and 5 washers from location (C) that hold the cover in place. Retain the bolts and washers for reassembly.
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   Illustration 15	g06147870

2. Disconnect red cable (E), purple cable (F), and jumper cable (J). Remove bus bar (D). Remove relay (G) and mounting bracket (H). Retain the mounting hardware for reassembly.
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   Illustration 16	g06147931
   (3) 7Y-7389 Screw (K) 9X-2040 Screw (4) 9X-8256 Washer (7) 515-2470 Plate As

3. Assemble new relay assembly mounting plate (7) using the hardware that is shown in Illustration 16. In location (K), use the screw that was removed in step 2
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   Illustration 17	g06147970
   (L) 9X-2046 Screw (6) 542-3264 Relay

4. Assemble relay (6) onto the mounting plate using the screws from location (L) that were removed in step 2. Only hand tighten the screws now.
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   Illustration 18	g06148004
   (M) 2 Bolt pass-through (1) 4B-4277 Washer (2) 5C-7261 Nut (5) 490-4245 Washer (Belleville) (E) Cable As (Red) (F) Cable As (Purple) (8) 515-2471 Bus Bar (Strap) (N) Washer (P) Nut

5. Assemble the new and reused parts using the hardware that is shown in Illustration 18.

   1. First, assemble bus bar (8) onto the 2 bolt pass-through at location (M).

   2. Next, assemble the 90˚ end of (red) cable assembly (E) onto the 2 bolt pass-through at location (M).

   3. Secure the cable assembly and bus bar by using washer (N) and nut (P) that were retained from step 2. Verify that the hardware stack-up matches the detail view in Illustration 18. Torque the nut to 15 ± 3 N·m (133 ± 27 lb in).

   4. Make sure that the jumper wire is secured with the adhesive backed mounting bases and cable ties as indicated in Illustration 18.

   5. Assemble the other end of bus bar (8) and the appropriate end of (purple) cable assembly (F) onto relay (6) by using washers (1), Belleville washers (5), and nuts (2). Verify that the hardware stack-up matches the detail view in Illustration 18. Torque the nuts to 15 ± 3 N·m (133 ± 27 lb in).

   6. Last, torque relay mounting screws (L) to 12 ± 3 N·m (106 ± 27 lb in).

6. Turn main battery disconnect switch to the ON position and verify that the system is operating properly.

7. When correct system operation has been verified, apply Caterpillar approved spray paint to the relay stud joints to prevent corrosion.

8. Reassemble the front battery cover using the bolts and washers that were removed in step 1c.

Installation Procedure For Group 4 Machines

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Illustration 19	g06142059

1. Locate the main power relay on the left-hand fender of the tractor.

   1. Turn main battery disconnect switch (A) to the OFF position.

   2. Open battery access cover (B).

   3. Remove the front battery cover by removing the 5 bolts and 5 washers from location (C) that hold the cover in place. Retain the bolts and washers for reassembly.
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   Illustration 20	g06143521

2. Remove bus bar (D), red cable (E), purple cable (F), and the relay (G). The parts and hardware may be discarded.
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   Illustration 21	g06384457
   (5) 5P-4115 Hard Washer (8) 7X-2534 Bolt (9) 089-7365 Washer (13) 542-3264 Relay

3. Assemble relay (13) using the hardware shown in Illustration 21. Only hand tighten the bolts now.
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   Illustration 22	g06384469
   (H) 2 Bolt pass-through (3) 7K-1181 Cable Strap (3) 4B-4277 Washer (4) 5C-7261 Nut (6) 6V-8801 Nut (7) 7X-0608 Hard Washer (10) 484-8948 Bus Bar (Strap) (11) 480-0089 Wiring Harness (12) 490-4245 Washer (Belleville) (14) 545-7258 Cable As (Purple) (15) 545-7259 Cable As (Red)

4. Assemble the new parts using the hardware that is shown in Illustration 22.

   1. First, assemble bus bar (10) onto the 2 bolt pass-through at location (H).

   2. Next, assemble the 90˚ end of (red) cable assembly (14) onto the 2 bolt pass-through at location (H).

   3. Secure the cable assembly by using washer (7) and nut (6). Verify that the hardware stack-up matches the detail view in Illustration 22. Torque the nut to 15 ± 3 N·m (133 ± 27 lb in).

   4. Assemble jumper wire (11) between the relay and the existing wire harness.

   5. Secure the jumper to the links (7T-1099) welded to the battery box using cable straps (2) as indicated in Illustration 22.

   6. Assemble the other end of bus bar (10) and the appropriate end of (purple) cable assembly (15) onto relay (13) by using washers (3), Belleville washers (12), and nuts (4). Verify that the hardware stack-up matches the detail view in Illustration 22. Torque the nuts to 15 ± 3 N·m (133 ± 27 lb in).

   7. Last, torque relay mounting bolts (8) to 12 ± 3 N·m (106 ± 27 lb in).
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   Illustration 23	g06384476
   (1) 3F-9556 Lockwasher (3) 4B-4277 Washer (4) 5C-7261 Nut (14) 545-7258 Cable As (Red) (15) 545-7259 Cable As (Purple)

5. Assemble the ends of the (red) cable assembly (14) and the (purple) cable assembly (15) onto the studs at the bottom of the fuse block as shown in the detail view in Illustration 23. Torque the nuts to 19 ± 1 N·m (168 ± 9 lb in).

6. Turn main battery disconnect switch to the ON position and verify that the system is operating properly.

7. When correct system operation has been verified, apply Caterpillar approved spray paint to the relay stud joints to prevent corrosion.

8. Reassemble the front battery cover using the bolts and washers that were removed in step 1c.