Suspension U-Bolt Torque Check

ep4 mm 32.02

Notice: Failure to retorque the U-bolt nuts could result in spring breakage and abnormal tire wear.

Check the U-bolt torque of both the front and rear axles where applicable.

  1. Park the vehicle on a level surface and apply the parking brakes. Chock the tires.
  2. Check the U-bolt torque. See Table for U-bolt torque specifications. Tighten in a diagonal pattern as shown in Fig.. Set a click-type torque wrench to the mid-point torque value for the fastener being checked. Turn the wrench in a clockwise motion (looking up) until the torque wrench clicks, then release pressure on the torque wrench, and turn the wrench again until it clicks. If the nut turns on the second application, the bolt is stretching and must be replaced. See General Information, Freightliner AirLiner Rear Suspension of the eCascadia™ Workshop Manual for bolt replacement procedures.

    Fig. 1, Tightening Pattern for U-Bolt High Nuts

    Table 1, Spring U-Bolt High Nut Torque Values

    Size

    Torque: lbf·ft (N·m)

    5/8–18

    180–230 (245–313)

    3/4–16

    270–330 (367–449)

    7/8–14

    420–500 (571–680)

    1–14

    520–600 (707–816)

    M20

    216–274 (292–372)

    M20 (Airtek)

    330–370 (447–502)

      Table 1, Spring U-Bolt High Nut Torque Values

    Note:
    Parent topic: Suspension
    Document Number: 0000121307
    Manual Publication Date: 2024-05-31
    Topic Publication Date: 2025-02-21