When an axle bearing begins to create a loud and unusual sound, it is typically a sign that the rear axle requires servicing. Whether the axle is about to break or has completely broken, the rear axles must be removed from the vehicle to repair and replace the differential assembly.
Axle seal leaks also warrant a rear axle service that requires the removal of the rear axles themselves. Axle seal leaks can occur from a drive axle boot malfunctioning and can severely damage the axle assembly.
Bearings in the carrier or on the axles that have become damaged or worn over time will typically produce a constant humming sound. These sounds will occur during acceleration, deceleration, and coasting.
Because the axle must always be removed from the vehicle, the steps in doing so will vary from vehicle to vehicle. As each vehicle's axle configuration may differ, it is important for those servicing axle bearings to consult the vehicle's manual for accurate instructions on how to remove and install an axle properly into the vehicle.
Eye protection should always be worn when removing an axle from a vehicle. During the removal process, it is possible for potential pieces of metal to fly out of the assembly and into the eyes of the servicer.
The collar and bearing should never be removed with a cutting torch, as the heat will result in the axle becoming weakened and damaged. The bearing and collar should never be pressed at the same time. The outer race should never be pressed on as bearing damage and an explosion can result.
Lubricant leaks in the rear axle can occur in several locations throughout the assembly, such as the inspection cover gaskets, the carrier, the pinion gear seal, and the two axle seals. The fluid will appear dark in color and will be oily. These leaks can show up on either the inside of the wheel and brake assembly or below the pinion gear or carrier.
It is easy for drivers to mistake an axle seal leak with a brake fluid leak, or vice versa. One should always touch the wet area and smell it to properly determine whether the fluid is indeed axle lubricant or brake fluid.
New axle seal should always be installed every time an axle assembly is being reinstalled into a vehicle. This should be done even if the seal already installed is fresh, as applying new seal after each removal and installation will ensure that the seal between the axle and axle seal is tight.
A slide hammer puller equipped with a hooknose can be used to remove a housing-mounted seal. The hook is placed on the metal part of the seal, and with an outward jerk of the tool's puller slide, the seal can be properly removed. A large screwdriver may be used as an alternative if a slide hammer puller is unavailable.
The bearing bore in the axle housing will almost always be at risk of being scratched or damaged when removing the seal. It is critical for those servicing a vehicle's axle seal to be cautious when dealing with axle seal removal.