Usage:
784B (5RK) Tractors;
785 (8GB),
785B (6HK) Off-Highway Trucks
Description of Change: The new one-piece wheel with higher capacity bearings will provide improved service life.
Adaptable To: The high capacity wheel bearings are effective with 784B (5RK026) Off-Highway Tractors and 785B (6HK735) Off-Highway Trucks. The 139-9584 Wheel (cast), 138-8722 Cone, 138-8719 Cone, and 138-8720 Cup are available. The new cups and cones are wider than previous bearings and can only be used with the new 139-9584 Wheel (cast). The 139-9584 Wheel (cast) requires 142-5129 or 142-5132 Demountable Rim Group (groups are not serviced).
Illustration 1.
Typical view of demountable rim group.
Wheel Bearing Adjustment Procedure For The Rear Wheels Of 784B Tractor And 785, 785B Off-Highway Truck Cast Wheel And High Capacity Bearings
Typical cross-sectional view of partially assembled wheel group.
Illustration 3.
View X. Gap = (A-B)
The following procedure must be used to adjust wheel bearings in the 142-5136, 142-5135, 140-7626, Rear Wheel Groups (groups are not serviced), 0R-9034 Rear Wheel Groups and 144-3854 Service Wheel Arrangement.
1. Thoroughly clean the tapped holes (6) in the end of the spindle to receive the retainer bolts (3).
2. With bearing assemblies (1) already in position, install retainer (2) using five new 1D-4610 Retainer Bolts (3). Install the retainer bolts in equally spaced hole positions. Tighten bolts in a crossing pattern to 200 N·m (150 lb ft).
3. Remove any lifting brackets or supports from under the wheel station.
4. Release the brakes. Refer to the "Towing" section in the Systems Operation, Testing and Adjusting (Air Systems and Brakes) module.
5. Turn the wheel two complete revolutions.
6. Retighten the retainer bolts (3) to 200 N·m (150 lb ft) using the same tightening sequence. Turn the wheel two complete revolutions.
7. Loosen all retainer bolts (3) in the same sequence by 120 degrees (two bolt head flats). Turn the wheel two complete revolutions.
8. Tighten retainer bolts (3) in a crossing pattern to 80 N·m (60 lb ft). Rotate the wheel two complete revolutions.
9. Repeat Step 8 until no further movement of the retainer bolts (3) occurs when a torque of 80 N·m (60 lb ft) is applied.
10. Use a depth micrometer and measure the average distance between the outside face of the retainer (2) to the end of the spindle. Measure two holes directly opposite each other and average the measurements. Refer to Illustration 3. Record Dimension B.
NOTE: If the two measurements differ by more than 0.13 mm (.005 in), , restart adjustment procedure beginning with Step 2. If the two measurements again differ by more than 0.13 mm (0.005 in), disassemble and check for any interference that would prevent correct seating of the wheel bearings. Record the average of the measurements and remove the retainer (2). Refer to Illustration 3.
NOTE: In addition to the hole pattern in the retaining plate for the retaining bolts, there are two holes which may be used to make the measurement indicated in Step 10.
11. Use an outside micrometer and measure the thickness of the retainer (2) at the bolt holes. Refer to Illustration 3. Record Dimension A.
12. Calculate the average gap between the end of the spindle and inside face of the retainer by subtracting dimension recorded in Step 10 from dimension recorded in Step 11.
13. Select and install the required shim pack (4).
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Do not install or reinstall the final drive screen assembly on trucks equipped with rear axle filtration.
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a. Shim pack requiredscreen assembly (5). To determine the required shim thickness, add 0.178 + 0.00/- 0.05 mm (.007 + .00/- .002 in) to the average gap found in Step 12.
b. Shim pack requiredscreen assembly (5). Determine the required shim thickness, add 0.178 + 0.00/- 0.05 mm (.007 + .00/- .002 in) to the average gap found in Step 12 and subtract the screen assembly thickness. Install screen assembly with the outside of the screen assembly against the retainer.
14. Install retainer (2) with ten new 1D-4610 Bolts (3) and ten new 5P-8248 Washers (7). Tighten bolts in a crossing pattern to a torque of 250 ± 25 N·m (184 ± 18 lb ft).
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Do not install previously torqued bolts or washers into final assembly.
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15. Repeat Step 14 until no further movement of the retainer bolts occurs when a torque of 250 ± 25 N·m (184 ± 18 lb ft) is applied.
16. Tighten each bolt an additional 60 ± 5 degrees.