An Automotive Worker’s Guide to Drive Axles

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A vehicle’s drive axles are one of the key elements in a vehicle’s wheel system. They are a necessary part for automotive professionals to understand so that the best possible maintenance can be performed. It’s also important to understand when axles aren’t working properly, and the ways in which they can be repaired.

Given how the axles collectively help the car with driving, steering and braking, as well as bringing torque and power to the wheels from the engine, it’s important to know how each of the car’s axles work, and what purpose they serve. Here’s a breakdown of each of a car’s drive axles, and how they function.

Front Axle: The Axle Doing Much of the Heavy Lifting

In a number of ways, the front axle is what truly helps keep the car moving smoothly. This is because it carries the weight of the vehicle’s front end, in addition to absorbing shocks from the road surface and assisting with steering. There are usually two types of front axles: dead front and live front. However, front axles are more commonly dead, meaning they do not rotate. Live front axles can often be found in four-wheel drive and in smaller vehicles. Live front axles transmit power from a transfer gearbox to a car’s front wheels. Its main function is to bring the car’s weight from its springs to the front wheels, converting the steering wheel’s rotary motion into the front wheels turning left or right.

The front axle not only carries the weight of the car, but absorbs shocks from the road
The front axle not only carries the weight of the car, but absorbs shocks from the road

Rear Axle: Helping to Keep Cars’ Wheels Afloat

Not only does the rear axle transmitting power between the driving and differential wheels, it is also the driving wheels for rear wheel-drive cars. Rare axles are also nearly all live axles, in that they revolve alongside the wheels. There are three types of rear axles: full floating, semi-floating, and three quarter floating. An automotive worker should understand that full floating rear axles are not supported by bearings and transmit power to the wheel hub without the pressure of the vehicle’s weight, while semi-floating axles have a bearing both on the axle and inside its casing—meaning the axle shaft would need to carry the weight of the vehicle. Three quarter floating axles are placed between the axle casing and the hub, with the car’s weight transferred to the axle casing.

The car’s rear axles revolve alongside the wheels and are usually live axles
The car’s rear axles revolve alongside the wheels and are usually live axles

Stub Axle: Another Part an Automotive Worker Can’t Ignore

Lastly, the stub axles are where the front wheels of the car are mounted, and the two are connected to one another via kingpins. Students in auto repair training should be aware that four different kinds of stub axles exist: Elliot, Lamoine, Reverse Elliot, and Reverse Lamoine. The Elliot axle’s arrangement is that of the yoke end having a kingpin and cotter join the stub axle to the front axle, and the Lamoine axle uses an L-shaped spindle instead of a yoke. The Reverse Elliot and Reverse Lamoine has these arrangements in the opposite order. Stub axles are typically found in the front of a rear-wheel drive car, and the rear for a front-wheel drive car.

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