Wheel studs, axle bearings and splines are all axle parts. Other axle parts are C-clips, differentials and ring gears. Features such as spring pads, differential covers and gaskets are also required to assemble axles. Many axle parts are specific to either a front or rear axle, such as the constant velocity joint (CV joint) and CV joint boot used on a front axle and the axle housing, pinion gears and differential cover found on a rear axle. Some parts, such as the king pins, king pin bushings and panhard bars, are unique to a straight front axle.
C-clips are the axle parts that secure the rear axle inside of the axle housing on some rear-wheel drive versions of the rear axle. The axle bearing is common on several types of axle and requires axle parts such as bearing retaining plates and locking collars. Some styles of axle use a two-piece axle, with the axle shaft and the axle flange making up the two pieces. The flange of this axle type uses splines and a section of square key stock to hold the axle together. Other modern axle parts include an exciter ring, which is used in anti-lock brake applications.
Occasionally, an axle will have shock absorber mounts attached to it. This is especially true with the rear axle in many front-wheel drive vehicles. This type of axle also has axle parts, such as spring pads and reinforcing plates that are used to strengthen the axle assembly. Much of these axles also have special mounts welded to the axle assembly to make attachment of the axle to the vehicle's chassis possible. This type of axle also uses a wheel nut to secure the wheel hub assembly to the axle.
In some front axle designs, axle parts are used to attach the steering gear to the axle. Drag links, sway bars and tie rod ends are all attached to a portion of the axle. This design also integrates the front leaf spring mounting pads into the axle casting. U-bolts and nuts are used to attach the springs to the axle beam. Small rubber pads are placed between the axle and the spring to act as a type of cushion and prevent squeaking. Critical axle parts to a front steering axle are the king pins that allow the steering knuckles to pivot on the axle, thus allowing the vehicle to turn and steer.