An axle boot is a part of a car which holds grease or lubricant for a smooth movement of the constant velocity wheel joints. These CV joints allow your car's front wheels to turn evenly while driving the car, especially during turns. These boots also keep dirt and other unnecessary material away from the joints so that they can move without any restriction.
Because of constant turns, The axle boots are one of several parts of a car's steering system that are greatly exposed to wear and tear. Some of these are fast rotating wheels, road debris and oil which dramatically accelerate wear and tear. More often than not, heat is the primary cause of boot failure, as the rubber can crack and cause grease to leak out. This heat can come from both the environment, exhaust from the engine bay, and the constant turning of the axle. In many cases, since these boots are hidden under a car, owners are usually surprised to find their car axle boots already damaged or worn. A regular check-up is therefore recommended, to prevent damaged boots, which can contribute to bigger issues.
Checking the axle boots is a relatively easy task with the right kinds of tools. Basically, you only need two things: A jack and safety stands.
- First, park your car in your garage or any level place which you can do car repairs. Turn your car engine off and pull the parking brake. If your car has automatic transmission, keep the gear selector in Neutral. If it's a manual, do the same. You need to turn your front wheels, so you should not lock the gear in place. You should also chock the rear wheels to make sure the car doesn't roll in the event of brake failure.
- Jack up the front portion of your car until you are able to inspect all of the bottom's parts. You can locate the axle boots at the end of each wheel axle, and these are connected to the constant velocity joints, attached to the front wheels. These appear as rubber boots, which are often cone-shaped and with an accordion-type surface. Check them for any sign of cracks, breaks and grease leakage.
- If you can see no damages in the primary inspection, slowly turn the wheels of the car. As you turn the wheels, inspect all portions of the boot for damage. Moreover, make sure that the boots move freely as you turn the wheels. Otherwise, the material might have already hardened. Continue to turn the wheels and listen for peculiar sounds or noises. In general, the boots should turn quietly or should not produce any scratchy sound.
- Once the checking is done, remove the safety stands and lower down the car using the jack.
If you find that there is a problem with the axle boots, such as cracks, leaks or breaks, then you need to replace it as soon as possible. Since this will involve removal of the wheel, and proper adjusting so that it is aligned properly with the rest of the steering system, you might have to consult with a professional for replacement. It's usually best to replace the boots in pairs. A car usually comes with four axle boots: the inner boots, which connect the CV joint to the transmission system, and the outer joints, which connect the CV joint with the wheel. These are both found on the left and right sides of the car.
Replacing or repairing the axle boots is so important that delaying its repair or replacement could spread the damage to other parts such as the transmission and suspension components. Having it checked regularly can prevent tedious and often expensive repairs. Checking is easy - you can do it yourself!