Procedure to Install the New Lower Hitch Group on the 525C, 535C, and 545C Wheel Skidders{7057, 7100} Caterpillar

Wheel Skidder:

525C (S/N: 5251-548)

535C (S/N: 5351-294)

545C (S/N: 5451-400)

Introduction

Do not perform any procedure in this Special Instruction until you read this information and you understand this information. The following Special Instruction contains the information that is required to install a new lower hitch assembly in 525C, 535C, and 545C Wheel Skidders.

The new design of the hitch improves the durability of the machine. The lower hitch now uses a nut for improved pin retention and uses match set bearings for easier assembly.

Affected Groups

Procedure for the 246-6008 Articulating Hitch Gp

Disassembly and Inspection for the 246-6008 Articulating Hitch Gp

1. Support the front and the rear frame in order to keep the machine stationary when the lower hitch pin is removed.

2. Remove the bolts and the washers from the plate for the pin retention.

3. Remove the bolts and the washers from the lower cap.

4. Remove the pin from the lower hitch.

5. Inspect the lower hitch plates for any spreading. If no spreading is present the distance between the lower face of the upper plate and the lower plate should be 156 ± 1 mm (6.2 ± 0.04 inch). If spreading is present the plates must be bent until spacing is within the specified dimensions.

6. Inspect the bores in the lower hitch plates for the front frame and the bearing bore for the rear frame. Refer to the column for the bore size in Table 2 for the proper bore size and the proper tolerance. The bore must be bored to an oversize diameter if the bore size is greater than the allowed tolerance. Refer to the column for the oversize criteria in Table 2 for the proper oversize bore diameter and the proper tolerances.
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   Table 2

   Criteria for the Oversize Bore Diameter for 246-6008 Articulating Hitch Gp
   246-6008 Articulating Hitch Gp	Oversize Criteria	Bore Size
   Upper Plate for the Front Frame	Greater than 98.53 mm (3.879 inch)	98.45 ± 0.05 mm (3.876 ± 0.002 inch)
   Lower Plate for the Front Frame	Greater than 98.53 mm (3.879 inch)	98.45 ± 0.05 mm (3.876 ± 0.002 inch)
   Bearing Plate for the Rear Frame	The bore must be within the tolerance.	139.96 ± 0.04 mm (5.510 ± 0.0016 inch)

7. If welding and boring are necessary the front and rear frames must be separated. Refer to Special Instruction, REHS1431, "Hitch Bore and Steering Cylinder Bore Dimensions for Wheel Skidders and Feller Bunchers" and Disassembly and Assembly, RENR4344, "Front Frame from Rear Frame - Separate".

8. If welding and boring are not required then proceed with the lower hitch assembly instructions.

Assembly of the 246-6008 Articulating Hitch Gp

Note: 154-9731 Thread Lock Compound should be applied before assembly to the lower 7X-2250 Bolts and the 8T-4183 Bolts . All surfaces should be clean from oil, grease, debris, and paint before applying 154-9731 Thread Lock Compound .

Illustrations for the 246-6008 Articulating Hitch Gp

Illustration 1	g01425485
(1) 295-1369 Nut (2) 095-1207 Nut (3) 7X-3150 Weld Stud (4) 5P-1076 Hard Washer (5) 308-7303 Plate (6) 295-0143 Sleeve Bearing (10) 8T-4223 Hard Washer (15) 118-8276 Shim Pack (19) 7V-8633 Spacer (20) 118-8272 Cap (21) 7X-2250 Bolt (22) 118-8275 Shim Pack (23) 143-7356 Tapered Roller Bearing (24) 118-8273 Cap (25) 7V-8632 Spacer (26) 299-5530 Lower Pin

Illustration 2	g01425488
(10) 8T-4223 Hard Washer (17) 8T-4183 Bolt

Illustration 3	g01445955
(10) 8T-4223 Hard Washer (18) 3B-8489 Grease Fitting (21) 7X-2550 Bolt

Procedure for Assembly of the 246-6008 Articulating Hitch Gp

1. Coat bores with multipurpose extreme pressure lubricating grease.

2. Install a 5K-0983 Lip Type Seal into both the upper and the lower cap.

3. Equally install three bolts around the lower cap. The three bolts will serve as a stop during installation of the bearing.

4. Cool the bearing assembly to −50° ± 5°C (−58° ± 9°F). Do not use liquid nitrogen to cool the bearings.

5. Install the entire bearing assembly in the bearing bore of the rear frame. Drive down the entire assembly by the cups only. Make sure that the entire bearing assembly makes contact with the cap. Do not hit the cones.

6. Remove the three bolts that were temporarily installed in Step 3 for the bearing installation.

7. Install the upper and the lower cap by using four of the seven bolts. Torque the bolts to 100 ± 20 N·m (74 ± 15 lb ft). Measure the gap between the upper cap and the frame. Install the 118-8275 Shim Pack (9) under the upper cap. The minimum measurement minus .010 inch (.25 mm) is the value of the shim. Do not exceed the measured gap.

8. Install the upper and the lower cap by using 7X-2550 Bolts (21) .

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Illustration 4	g01425494
Tightening sequence

9. Hand tighten the cap bolts until contact is made with the frame. Torque the cap bolts to 100 ± 20 N·m (74 ± 15 lb ft). Refer to Illustration 4 for the proper tightening sequence.

10. Measure the rolling torque by rotating the tapered roller bearing by using a torque wrench 3 N·m (27 lb in) to 5.6 N·m (50 lb in). If the rolling torque is outside this range reassemble the bearings with the correct rolling torque.

11. Freeze the lower hitch pin to −50° ± 5°C (−58° ± 9°F). Do not use liquid nitrogen to cool the pin.

12. Install the lower hitch pin with three of the 8T-4183 Bolts (17) .

13. Measure the gap between the frame and the pin all the way around. The minimum measurement minus 0.25 mm (0.0098 inch) equals the value of the shim.

14. Slightly lower the lower hitch pin in order to allow space for the shim pack. Cut the shims into two equal halves. Cutting the shims is necessary for installation around the pin. Do not cut across bolt holes on the shim.

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Illustration 5	g01425496
Tightening sequence

15. Install the six 8T-4183 Bolts (17) by hand. Then torque the bolts to 100 ± 20 N·m (74 ± 15 lb ft). Torque the bolts by using the tightening sequence in Illustration 5. Apply 154-9731 Thread Lock Compound to the bolted joint.

16. Install the 295-1369 Nut and then torque the nut to 500 ± 50 N·m (368 ± 36 lb ft).

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Illustration 6	g01442203

17. Install 308-7303 Plate (5) over 295-1369 Nut (1) and 7X-3150 Weld Stud (3). Use a fixture to locate 7X-3150 Weld Stud (3). Refer to Illustration 6 for the proper orientation.

18. Place 7X-3150 Weld Stud (3) on the frame and weld a 5 mm (0.2 inch) fillet all the way around the diameter.

19. Install 308-7303 Plate (5) over the nut and the weld stud. Install 5P-1076 Hard Washer and 095-1207 Nut and tighten to 100 ± 20 N·m (74 ± 15 lb ft).