parts differ vastly between afront axle
that drives the vehicle and an axle that is used strictly to steer the vehicle. An axle that actually drives the vehicle uses frontaxle parts
such as constant velocity (CV
) joints, wheel bearings and grease seals. A steering axle contains far fewer front axle parts, such as spring pads, king pin bushings and king pins.
In a front-wheel drive application, the axle typically passes through a bearing support. The support is suspended between a strut, or upper A-frame, and the lower strut arm, or A-frame, so this type of axle does not require an axle bearing. This type of drive system uses front axle parts such as a CV joint and a boot, which is a rubber cover used to protect the CV joint as well as retain the CV lubricant.
This axle is made up of two separate axles connected by the CV joint. The long axle section is inserted into the transaxle splines to actually power the axle. The shorter section of the axle is connected to the long section by the CV joint and passes through the wheel hub and is inserted into the wheel hub's drive flange or splines.
A steering-only axle uses a beam-type axle that includes one of two methods to position the axle. The solid beam type axle can be suspended over or under a leaf spring by axle pads cast into the axle and U-bolts. A tubular axle also uses the U-bolt system, however, other front axle parts include weld-on spring perches and U-bolts.
Other front axle parts for both styles of axle include king pin bushings and king pins that are used to connect the steering knuckles to the axle. King pin bushings can be made from plastic, bronze or aluminum, and are used to act as a type of bearing for the king pins, a solid steel shaft used to affix the steering knuckle to the axle and provide a pivot to allow steering.
Other front axle parts, such as shock absorber mounts, act to cushion the ride of the vehicle while steering stabilizer mounts allow a steering stabilizer to be mounted to the axle and the frame to aid in the resistance of bump steer. The steering-only axle also includes front axle parts such as wheel bearings, washers and a castelated nut to fasten the wheel onto the short spindles. Some old-style front axles, such as those used on early 1930s vehicles, include front axle parts such as radius arm attaching brackets and mounts to position the axle squarely in the frame rails through the use of a radius arm.