A front axle is a rotating shaft at the front of a vehicle that turns the front wheels. Vehicle design can be quite variable, and axles come in a range of formats and designs to meet different needs. Replacement of a front axle may be necessary in the wake of a serious accident or other damage, like heavy rusting. Replacement parts are available through manufacturers as well as junkyards, where it may be possible to find matches for older vehicles that cannot be purchased readily through the open market.
While drivers often think of the front axle as a simple shaft, the axle is actually most commonly split in two, with a differential between the two segments. The differential allows the wheels to turn at different speeds while the vehicle is turning. This increases traction, smooths handling, and makes the vehicle easier to control. When the car's alignment is straight, the wheels can turn at the same rate of speed.
Sometimes a front axle is a driving axle, while in other cases it is non-driving, depending on the car design. Front wheel drive cars use the front axle to drive and steer, while the rear axle simply follows. In a rear wheel drive car, the opposite is the case. Some vehicles are all wheel drive, or can switch between two and four wheel drive depending on the circumstances. All wheel drive can be useful for rough terrain and certain other situations where higher traction and control are necessary.
When a front axle needs replacement, the process can be involved. A mechanic will need to remove the wheels and other components and may need to disconnect parts of the drive train to free the axle for removal. After it is taken off, the mechanic can inspect the systems in the car to check for signs of damage and other issues, and then fit the new axle, secure it, and replace the other components. She should then test the car to confirm that it handles properly.
The height of the car above the front axle can vary, depending on design. Some cars have larger shocks and springs to position the vehicle's center of gravity higher, while others may be low to the ground, as in the case of sports cars and race cars. A car with a higher center of gravity can be more prone to tipping and may be more difficult to control, unlike a low-slung car that tends to corner well and resist tipping forces.