Maintaining Your Hubs

From our friends over at Dexter Axle, here are a few tips for maintaining your hubs and bearings.

Hub Removal - Standard Bearings

Whenever the hub equipment on your axle must be removed for inspection or maintenance the following procedure should be utilized.
  1. Elevate and support the trailer unit per manufacturers’ instructions.
  2. Remove the wheel.
  3. Remove the grease cap by carefully prying progressively around the flange of the cap. If the hub is an oil lube type, then the cap can be removed by unscrewing it counterclockwise while holding the hub stationary.
  4. Remove the cotter pin from the spindle nut or, bend the locking tang to the free position. Gently pry off retainer from the nut and set aside.
  5. Unscrew the spindle nut (counterclockwise) and remove the spindle washer.
  6. Remove the hub from the spindle, being careful not to allow the outer bearing cone to fall out. The inner bearing cone will be retained by the seal.
  7. For 7,200 lb. and 8,000 lb. axles, a hub puller should be used to assist in drum removal.

Bearing Lubrication - Grease

Along with bearing adjustment, proper lubrication is essential to the proper function and reliability of your trailer axle. Bearings should be lubricated every 12 months or 12,000 miles. The method to repack bearing cones is as follows:
  1. Place a quantity of grease into the palm of your hand.
  2. Press a section of the widest end of the bearing into the outer edge of the grease pile closest to the thumb forcing grease into the interior of the bearing.
  3. Repeat this while rotating the bearing from roller to roller.
  4. Continue this process until you have the entire bearing completely filled with grease.
  5. Before reinstalling, apply a light coat of grease on the bearing cup.

Bearing Lubrication - Oil

If your axles are equipped with oil lubricated hubs, periodically check and refill the hub as necessary with a high quality hypoid gear oil to the level indicated on the clear plastic oil cap. The oil can be filled from either the oil fill hole, if present, in the hub or through the rubber plug hole in the cap itself.

Bearing Adjustment and Hub Replacement

If the hub has been removed or bearing adjustment is required, the following adjustment procedure must be followed:
  1. After placing the hub, bearings, washers, and spindle nut back on the axle spindle in reverse order as detailed in the previous section on hub removal, rotate the hub assembly slowly while tightening the spindle nut to approximately 50 lbs.-ft (12" wrench or pliers with full hand force).
  2. Then loosen the spindle nut to remove the torque. Do not rotate the hub.
  3. Finger tighten the spindle nut until just snug.
  4. Back the spindle nut out slightly until the first castellation lines up with the cotter key hole and insert the cotter pin (or locking tang).
  5. Bend over the cotter pin legs to secure the nut (or locking tang).
  6. Nut should be free to move with only restraint being the cotter pin (or locking tang).
For axles using the new nut retainer:
  1. Finger tighten the nut until just snug, align the retainer to the machined flat on the spindle and press the retainer onto the nut. The retainer should snap into place. Once in place, the retainer/nut assembly should be free to move slightly.
  2. If the nut is too tight, remove the retainer and back the nut off approximately one twelfth of a turn and reinstall the retainer. The nut should now be free to move slightly.
  3. Reinstall grease cap.

Zerk Fitting Lubrication

The procedure is as follows:
Spindle with Zerk Fitting
  1. Remove the rubber plug from the end of the grease cap.
  2. Place a standard grease gun onto the grease fitting located in the end of the spindle. Make sure the grease gun nozzle is fully engaged on the fitting.
  3. Pump grease into the fitting. The old displaced grease will begin to flow back out the cap around the grease gun nozzle.
  4. When the new clean grease is observed, remove the grease gun, wipe off any excess, and replace the rubber plug in the cap.
  5. Rotate hub or drum while adding grease.