Fontaine

49X mm 31.01.003
  1. Disconnect the tractor from the trailer. For instructions, see the 47X and 49X Driver's Manual. 
  2. Thoroughly steam clean the fifth wheel.
  3. Check for cracks in the fifth wheel assembly, mounting brackets, and mounting parts.
  4. Ensure that both bracket pins are in place and secured by retainer pins and cotter pins. See Fig..

    6000 Series shown; 7000 Series fifth wheels use similar parts.

    1. Tightening Screw Hex

    2. Flat Washer, 5/8"

    3. Wedge Stop Rod Spring

    4. Wedge Stop Rod

    5. Grease Fitting

    6. Bracket Pin

    7. Bracket Retainer Pin

    8. Cotter Pin, 3/16" x 1"

    9. Bumper Spring

    10. Handle Spring

    11. Bolt, Secondary Safety Lock

    12. Flat Washer

    13. Secondary Safety Lock

    14. Bushing, Secondary Safety Lock

    15. Hex Locknut

    16. Pull Handle

    17. Bolt, Bumper

    18. Bushing

    19. Bumper

    20. Timer Spring

    21. Timer

    22. Operating Handle

    23. Bolt, Operating Handle

    24. Bushing, Operating Handle

    25. Hair Pin Cotter

    26. Wedge

    27. Step Jaw

    Fig. 1, Fontaine Fifth Wheel

  5. For fifth wheels equipped with bracket liners, rock the fifth wheel. If it does not rock freely, remove the top plate and inspect the bracket liners. Replace liners that are broken or less than 0.125 inch (3 mm). For the liner replacement procedure, see the Fontaine website,www.fifthwheel.com.
  6. Check the jaw and stationary jaw for mushrooming, and check that the serrations at the jaw and wedge are in good condition and not fully worn flat.
  7. Test the secondary safety lock latch for ease of operation.
  8. Check for loose nuts or bolts on the fifth wheel and the mounting. The secondary safety lock, bumper and operating handle bolts should be torqued to not more than 80 - 90 N.m (59 - 66 ft-lbs). The wedge stop rod bolt should be torqued to 4.1 - 20.4 N.m (3 – 15 ft-lbs). Set a torque wrench to the maximum torque value for the bolt being checked, and confirm that the torque is to specification. Do not loosen the bolt to check the torque. For torque specifications, see  of the 47X and 49X Driver's Manual. 
  9. Check all springs to see if they are securely fastened, and are not deformed.

    10. Warning: Close the fifth wheel on a standard 2-inch (50-mm) kingpin or similar 2-inch (50-mm) diameter shaft so that it locks.

  10. Check the wedge adjustment.
    1. Push on the wedge stop rod with hand pressure. It should move in 1/4 inch (6 mm) and spring back out on release. If the free travel is not 1/4 inch (6 mm), adjust the distance to 1/4 inch (6 mm) by turning the wedge stop rod, on the right side of the top plate, clockwise to reduce the gap and counter-clockwise to increase it.
  11. Replace cracked, worn, or damaged parts with new parts. Replace all loose mounting bolts with 5/8–11 SAE grade 8 bolts, grade C locknuts, and hardened washers. Do not re-use bolts, nuts, and washers on fifth wheel mountings.
  12. After inspecting the fifth wheel, lubricate all moving parts with a chassis or multipurpose grease. Apply a generous coating of grease to the top plate to fill the grooves, or depressions, on the top plate. Lubricate grease channels in the top plate using a lithium complex grease, suitable for use in high pressure applications. For cold weather applications, use a less viscous lubricant such as 90-weight oil, diesel fuel, kerosene, motor oil, etc. See MOP 31–02 in this manual for lubrication instructions.
Note:
Parent topic: Fifth Wheel Inspection
Document Number: 0000118696
Manual Publication Date: 2024-05-16
Topic Publication Date: 2024-10-31