Hub and Wheel Bearings Wheel bearings allow the wheel to turn freely. The bearings may be either tapered roller bearings or ball bearings. If the spindle shaft is fixed (cannot turn), then the outer housing or hub will turn. If the outer housing is fixed (cannot turn), then the drive shaft or axle can turn freely. Bearings are held between inner and outer races, and depending on which one is fixed, inner or outer can turn freely. Tapered roller bearings Ball bearings Races

Axle Shafts (Half Shafts) And Rear Hub/Bearings Generally Used With Non Independent Suspension Systems. Rear wheel Drive Vehicles

Semi Floating Shown here is a typical axle hub arrangement used on many non independent rear wheel drive cars. A single bearing is used, which is mounted in the axle casing. With this design, the axle shaft has to withstand all the operating forces such as, torsional,bending,shear,tension and compression. An oil seal is fitted to prevent loss of lubricating oil from the final drive/differential assembly.

Three Quarter Floating The three quarter floating bearing shown here reduces the main shear stresses on the haft shaft, but the other stresses remain. The bearing is mounted on the outside of the axle casing. A oil seal is used to prevent loss of lubricating oil from the final drive/differential.

Fully Floating Fully floating systems are generally used on heavy, or off road vehicles. This is because the stresses on these applications are greater. Two widely spaced bearings are used which take all the load. Other than torque, off the axle shaft. Bolts or studs are used to connect the half shaft to the wheel hub. When these are removed, the half shaft can be removed without jacking up the vehicle.

Driven Wheels (Live Axle) Independent Suspension The Outer drive axle is splined onto the hub. The Bearings can be either ball or roller. Some vehicles use a special Axle washer. A Steering knuckle/Stub Axle Carrier or support holds the wheel bearings. The Drive hub wheel mount transfers power to the wheels. A Hub nut secures the hub to the drive axle. A CV boot prevents water and dirt entering the joint and stops lubricant leakage. Steering knuckle/Stub Axle Carrier Outer drive axle Drive hub Hub nut CV boot Bearings Axle washer

Bearing Assemblies/Independent Suspension Wheel stud Brake disc Splash guard fixing screw Hub nut Drive hub Splash guard Circlip Seal CV bearing race Outer bearing Steering knuckle/Stub Axle Carrier Inner bearing CV boot CV joint Spacer Axle washer

Non-driven (Dead Axle) Wheel Bearings The Spindle/Stub Axle is a fixed (non-turning) shaft. The Wheel bearings are tapered roller bearings. The Hub holds the brake disc or drum. A Grease seal prevents loss of lubricant. A Nut adjusts the wheel bearing. A Split pin prevents the nut turning. A Dust cap keeps grease in and road dirt out. Spindle Dust cap Split pin Hub Wheel studs Grease seal Brake disc Wheel bearings Back plate Nut

Dust cap Nut and locking device Split pin Washer Outer bearing race Brake disc Inner bearing race Seal Back plate Steering knuckle/Stub Axle Carrier Spindle/Stub Axle Hub and wheel studs Non-driven (Dead Axle) Wheel Bearings Independent Suspension