2010/10/06 Caterpillar

Off-Highway Truck/Tractor:

777F (S/N: WTK1-UP)

777F (S/N: JRP1-UP; JXP1-UP)

ReferenceSpecial Instruction, REHS1841, "General Welding Procedures"

Description of Change: The new handrail assembly does not obstruct the view in the upper mirror in the mirror assembly. The operator will be able to view the loader pin when spotting the truck under the loader.

Adaptable To: The new 362-1712 Handrail As is a direct replacement for the former 273-8920 Handrail As in the 273-2387 Handrail Gp .

The new handrail assembly is adaptable to machines WTK1-UP, JXP1-158, and JRP1-2469.

The new handrail assembly became effective in production with the machines JXP159-UP, and JRP2470-UP.

Use the following procedure to install the new 362-1712 Handrail As on earlier machines. Use the second procedure to update the former 273-8920 Handrail As to the new 362-1712 Handrail As .

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Illustration 1	g02173718

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Illustration 2	g02173720
View of area (A)

1. Remove the four bolts (5) and four washers (6) from the two mirror assemblies (7). Remove the two mirror assemblies from the tube assemblies. Save all of the parts.

2. Remove the four bolts (8), the four washers (9), and the four supports (10) from the two tube assemblies (11). Remove the two tube assemblies. Save all of the parts.

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Illustration 3	g02173753
View of area (B)

3. Remove the following parts that attach the 273-8920 Handrail As to the 273-8294 Handrail As. Save all of the parts.
   • One nut (16)

   • Two washers (15)

   • One bolt (14)

   • Two clips (12)

   • One grommet (13)

4. Attach a suitable lifting device to the handrail assembly. The approximate weight of the handrail assembly is 19 kg (42 lb).

5. Refer to Illustration 1. Remove the 12 bolts (1) and the 12 washers (2) that attach the handrail assembly to the platform. Save the parts.

   Note: The bolts in the platform and the bolts in the stairs are not the same parts. Do not mix the two bolts.

6. Remove the 12 bolts (3) and the 12 washers (4) that attach the handrail assembly to the stairway. Save the parts.

7. Remove the 273-8920 Handrail As from the machine.

8. By using a suitable lifting device, install the new 362-1712 Handrail As to the machine. The approximate weight of the handrail assembly is 23 kg (51 lb).

9. By using the 12 bolts (1) and the 12 washers (2) that were saved in Step 5, attach the handrail assembly to the platform.

10. By using the 12 bolts (3) and the 12 washers (4) that were saved in Step 6, attach the handrail assembly to the stairs.

11. Torque the 24 bolts to 55 ± 10 N·m (41 ± 7 lb ft).

12. By using the parts that were saved in Step 3, attach the new 362-1712 Handrail As to the 273-8294 Handrail As .

13. By using the parts that were saved in Step 2, attach the two tube assemblies to the handrail assembly. Torque the bolts to 105 ± 20 N·m (77 ± 15 lb ft)

14. By using the parts that were saved in Step 1, attach the two mirror assemblies to the two tube assemblies. Torque the bolts to 47 ± 9 N·m (35 ± 7 lb ft)

Procedure to Update the former 273-8920 Handrail As to the new 362-1712 Handrail As

Illustration 4	g02174100
(1) A 1190.40mm (46.866 inch) length of tubing with an outside diameter of 33.4 mm (1.32 inch) and a wall thickness of 3.38 mm (0.133 inch) (A) Radius 101.6 mm (4.00 inch) in two places (B) 574.2 mm (22.61 inch) centerline to centerline of tube (C) 389.3 mm (15.33 inch) centerline of tube to bottom of tube (D) 226.9 mm (8.93 inch) centerline of tube to end of tube (E) 257.0 mm (10.12 inch) centerline to centerline of tubes (F) 550.0 mm (21.65 inch) centerline to centerline of tubes (W1) 3.0 mm (0.12 inch) fillet weld all around the tubes (W2) 3.0 mm (0.12 inch) fillet weld all around the tubes (W3) 3.0 mm (0.12 inch) fillet weld all around the tubes

1. By using the dimensions in Illustration 4, form tube (1) into the proper shape.

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Illustration 5	g02174415
View of area (G) (H) 3.0 mm (0.12 inch) by 45 degree chamfer all around the two tubes (J) 8.0 mm (0.32 inch) diameter hole in eight places (K) 50.8 mm (2.00 inch) (L) 60.0 mm (2.36 inch) from the end of tube (8) (W4) 3.0 mm (0.12 inch) V-groove weld all around the tubes (W5) 3.0 mm (0.12 inch) spot weld grind flush in eight places

2. Refer to Illustration 5. Position and drill two holes through both sides of tube (7) .

3. By using the dimensions in Illustration 5, position and drill two holes through both sides of the end of tube (1) that will touch tube (7) .

4. Remove tube (2) from the handrail assembly. Cut tube (2) on the side of tube (7) that is the farthest away from square tube (6). Save tube (2) .

5. Remove tube (4) from the handrail assembly. Be sure to cut the tube so that the radius that fits tube (7) is left on the end of the tube (4). Save tube (4) .

6. At the cut line for tube (2), form a radius on the end of tube (8). The radius will allow tube (1) to be welded to tube (8) .

7. Cut a rod that has a diameter of 25.4 mm (1.00 inch) to a length of 275 mm (10.8 inch).

8. Prepare the area around the holes for welding. For the proper procedure, refer to Special Instruction, REHS1841, "General Welding Procedures".

9. Insert one-half of the length of the rod into tube (7). Tack-weld the rod to the tube through the two holes in tube (7) .

10. Insert the long end of tube (1) onto the rod. Place the short end of tube (1) on the top of square tube (6). Mark the position on the top of square tube (6) for tube (1) .

11. Prepare the top of the square tube for welding. For the proper procedure, refer to Special Instruction, REHS1841, "General Welding Procedures".

12. Tack-weld the long end of the tube through the two holes in the tube. Tack-weld the short end of the tube to the top of the square tube (6) .

13. Cut the length of tube (2) to match tube (4). Cut a radius on the end of tube (2) that fits tube (7). Tube (2) should match tube (4) .

14. Position tube (2) at position (3). Mark the position for the tube.

15. Prepare the area for welding. For the proper procedure, refer to Special Instruction, REHS1841, "General Welding Procedures".

16. Tack weld tube (2) to tube (7) and tube (6) .

17. Position tube (4) at position (5). Mark the position for the tube.

18. Prepare the area for welding. For the proper procedure, refer to Special Instruction, REHS1841, "General Welding Procedures".

19. Tack weld tube (4) to tube (7) and tube (6) .

20. Weld tube (1) to tube (7) at the eight holes (J) .

21. Weld the end of tube (1) to the end of tube (7) .

    Note: The welds in Step 21, Step 22, Step 23, Step 24, and Step 25 must meet the following specifications: AWS A5.1 E7018, AWS A5.18 ER70S-2, AWS A5.18 ER70S-3, AWS A5.18 ER70S-6, AWS A5.18 ER70C-6M, AWS A5.20 E70T-1, AWS A5.20 E70T-5, AWS A5.20 E71T-1, AWS A5.17 F7A2-EM12K and AWS A5.17 F7A2-EM13K

22. Weld the end of tube (1) to the top of tube (6).

23. Weld tube (2) to tube (7) and tube (6) .

24. Weld tube (4) to tube (7) and tube (6) .

25. Weld tube (8) to tube (1) .