As much as 90% of all wheel end seal failures are a result of improper installations, according to SKF.
The manufacturer offers a systems approach to wheel-end maintenance in its Trouble Free Operation program, by providing fleets with detailed instructional materials and making hands-on training available to technicians.
The following tips are from the program’s Wheel-End Maintenance Guide.
Removal of the wheel assembly should always be done with a wheel dolly.
Grease or oil seals should be removed with a special seal removal tool to avoid damage to the hub. New seals must always be used in replacement.
Bearings and seals should be inspected for wear or signs of probable failure.
Bearing cups should be installed using a special bearing installation tool. A hammer should never be used directly to drive bearing cups into position!
Seat seals in the bore using a special installation tool with centering plug. Never use direct hammer blows on the seal it will destroy the seal’s ability to contain lubricants and protect the bearings.
Re-mounting of the wheel assembly on the spindle should always be done using a wheel dolly. Be careful in moving the assembly onto the spindle because it is necessary to avoid damaging the seal.
Spindle nut torque adjustment should follow the manufacturer’s specification on TMC RP618. Endplay adjustment should be verified using a portable dial indicator.
Inspection of grease or oil can provide a clue to other problems. Remove a sample from the wheel end and check condition of the lube:
Cloudy or milky indicates water
Shiny indicates bearing wear
Metal flakes present could indicate loose shavings from an axle component
Grit and sand indicates lube contamination
Burnt smell indicates overheating
Bearings must be cleaned for inspection and re-use. Use only clean solvents. Good cleaning requires proper equipment such as a solvent bath and a filter system with regular changes of both.
Do not use compressed air. Air jets cause small abrasive particles to become jammed in between the bearing surfaces.
After cleaning, dry with a clean paper towel or a clean rag. Prior to re-installing bearings, always check for the proper lubricant. The truck or trailer manufacturer has pre-determined that the wheel-end assembly is to be lubricated by either grease or oil. The importance of following the manufacturer’s specifications cannot be over emphasized.
Always use specified lubricant
Do not mix lubricants. Chemical interaction between lubricants and seal materials can damage the seal
For proper lubrication, the grease must be packed into the cavities between the rollers and cage of the bearing cone. A mechanical grease packer is recommended
Apply a light film of grease to the axle spindle for corrosion protection.
It is important to not mix wheel-end components bearings are “mates” that wear together. This includes new bearings.