Wheel bearings are high-load components and are critical to safe trailer operation. They must be inspected and regreased at least every 12 months, or more frequently depending on usage conditions.

When servicing bearings, always replace:

• Split pins
• Bearing seals (one per axle)

Inner and outer bearings must be replaced if signs of wear, pitting, corrosion, or scoring are present.

Wheel Bearing Service Procedure

Before commencing, ensure you have appropriate tools, high-temperature bearing grease, replacement seals, and split pins.

Step 1 – Preparation

• Park the trailer on a level surface and keep it connected to the tow vehicle.
• Chock the opposite wheel securely.
• Loosen the wheel nuts on the wheel being serviced (approximately half a turn).
• Jack up the trailer and support the chassis safely using axle stands.
• Remove the wheel nuts and wheel.
• Carefully remove the dust cap using multi-grips or gentle tapping with a screwdriver and hammer if necessary.

Step 2 – Remove Axle Nut

• Straighten and remove the split pin using pliers.
• Undo and remove the axle nut.

Step 3 – Remove Bearings

• Remove the outer washer and outer bearing.
• Slide the hub assembly off the axle.
• The inner bearing and seal will remain inside the hub.
• Carefully remove the seal first, then extract the inner bearing for inspection.

Step 4 – Inspect Components

• Thoroughly clean bearings using a suitable degreaser.
• Dry completely before inspection.
• Examine rollers and bearing surfaces for:

• Pitting
• Scoring
• Corrosion
• Discolouration

Inspect bearing cones/races for surface imperfections. If any defects are detected, replace bearings and races as a complete set.

Step 5 – Regrease Bearings

• Use high-temperature wheel bearing grease.
• Pack grease thoroughly into the bearing rollers by hand or with a bearing packing tool.
• Ensure grease penetrates fully through the bearing assembly.

Step 6 – Clean Hub & Reassemble

• Clean the internal hub cavity using a suitable solvent (e.g., wax and grease remover).
• Reinstall the inner bearing.
• Fit a new bearing seal, ensuring it sits flush (use a wooden block if tapping into place).
• Clean the axle spindle thoroughly before refitting the hub.
• Slide the hub onto the axle.
• Reinstall the outer bearing and washer.

Step 7 – Adjust Bearing Tension

• Tighten the axle nut firmly while rotating the hub.
• Back off the nut until the hub rotates freely.
• Align the nut to the nearest split pin hole and insert a new split pin.
• Secure the split pin by bending it firmly into position.
• Refit the dust cap.

Step 8 – Refit Wheel

• Reinstall the wheel (if not already done).
• Tighten wheel nuts sufficiently while elevated.
• Spin the wheel to confirm smooth rotation.
• Check for vertical movement by holding the top and bottom of the tyre:

• Excess play indicates loose adjustment.
• Binding indicates over-tightening.
  • Lower the trailer and torque wheel nuts to specification.

Step 9 – Post-Service Check

After approximately 150km of travel:

• Recheck wheel nut torque.
• Check for bearing movement.
• Confirm the hub temperature:

• Hub should be cool to slightly warm.
• Excessive heat indicates over-tightening or bearing damage.

Important – New Trailers

For new trailers, wheel nut tension and bearing adjustment must be checked after the first 150km of operation.