Castloc II and Simplex Series

4700 mm 31.01.004
  1. Disconnect the tractor from the trailer. For instructions, see Chapter 10 of the Western Star Driver's Manual.
  2. Thoroughly steam clean the fifth wheel.
  3. Check the fifth wheel plate for cracks. Check for sharp edges on top; the chamfer should be 1/8 to 1/4 inch (3 to 6 mm).
  4. When the wheel is locked, the safety latch must swing free and fall freely into position. See Fig..

    1. Lubricant Grooves

    2. Safety Latch

    3. Lock Control Handle

    4. Mount

    Fig. 1, Simplex Series Fifth Wheel

  5. The lever bar and operating handle must be in proper alignment. See Fig. Compare the lever bar and operating handle alignment to a new, or a properly operating lever bar and operating handle. Replace any bent or misaligned lever bar or operating rod.

    1. Operating Handle

    2. Lever Bar

    Fig. 2, Lever Bar and Operating Handle Alignment

  6. Check all cotter pins for cracking or damage. Replace any cotter pin that shows any signs of damage.
  7. Level the fifth wheel plate to a horizontal position. Measure the height from a stationary mounting point (see Fig. , item 3), such as the frame rail to the top of the fifth wheel plate (item 1). Pry up on the fifth wheel plate (item 4) below the pin boss, and measure the vertical movement (item 5). The bracket connection provides a 9/32 inch (7 mm) vertical clearance to provide cushioning and to avoid downward pin-loading while retaining minimum plate lift. If the plate lift (Ref. A) exceeds 5/16 inch (8 mm) as a result of wear or rubber deterioration, install new bracket-shoe rubber pads.

    • Extended Top Plate Lift Height

    1. Fifth Wheel Top Plate

    2. Fifth Wheel Frame Mount

    3. Frame Rail

    4. Lifting Point

    5. Static Top Plate Height

    Fig. 3, Measuring Fifth Wheel Top Plate Lift

  8. Check all mounting bolts for signs of fatigue, and tighten them to the proper torque. For torque specifications, see . Inspect all angles, plates, and brackets for cracks or other damage.
  9. Replace cracked, worn, or damaged parts with new parts. Replace all loose mounting bolts with 5/8–11 Grade 8 bolts, Grade C locknuts, and hardened washers. Do not re-use bolts, nuts, and washers on fifth wheel mountings.
  10. After inspecting the fifth wheel, lubricate all moving parts with a chassis or multipurpose grease. See Maintenance Operation 31–02 for lubrication instructions.
Note:
Parent topic: Fifth Wheel Inspection
Document Number: 0000120676
Manual Publication Date: 2024-05-23
Topic Publication Date: 2024-10-31