1996 Ford Aerostar Owner's Manual - Page 274

Wheel Inspection and Maintenance Check for damage that would affect the runout of the wheels. Wobble or shimmy will eventually damage the wheel bearings. Front wheel bearings require periodic repacking and adjustment as specified in the Maintenance Schedule and Record booklet. Loose or worn front wheel bearings tend to let the vehicle wander or shimmy, and can eventually cause excessive tire wear. Whenever a wheel is removed and then re-installed, always remove any corrosion that may be present on the mounting surface of the wheel and/or the surface of the hub, drum or rotor that contacts the wheel. RWARNING Installing wheels without good metal-to-metal contact at the wheel mounting surface can cause the wheel lug nuts to loosen and could allow the wheel to come off while the vehicle is in motion. RWARNING On-vehicle wheel balancing will cause damage to the drivetrain of E-4WD Aerostars. 296