What is the CV Boot?
The engine generates power by burning fuel, but how does that power transfer to the wheels that move you? The engine is connected to the transmission or transaxle, where the engine’s rotation can be controlled and given direction. There are axle shafts that link the transaxle to the front wheels on cars with front wheel propulsion. A driveshaft links the transmission to a rear differential on some cars, which may also use constant velocity axle shafts depending on the make. These axle shafts use a universal joint to be able to continuously spin despite not being in a straight line with the transmission or differential. When the suspension goes up and down, the universal joint allows the axle shaft to ‘flex’ without binding. This constant velocity, or CV joint, is encased in a rubber boot known as a CV boot. The CV boot is filled with grease to lubricate the CV joint and stop corrosion inside the boot. There are clamps on either side of the boot to keep axle grease from leaking. If the CV joint starts a crack or one of the clamps breaks or becomes loose, grease will leak out of the CV boot and can make water to get into the CV joint.
Bear in mind:
- Water is the enemy of your constant velocity joints. Any water in your CV boot can cause premature failure.
- The constant velocity boot is rubber and therefore suceptible to weather cracking.
How it is done:
- The CV Boot is checked that it needs to be changed. The car is raised and supported on jack stands and the wheel is removed.
- The defective CV Boot is taken out by removing the axle and disassembling it to change the boot and clean the joint.
- The new CV Boot is mounted by packing the joint with CV grease, reassembling the axle, and attaching the new boot.
- The CV Boot is test run for operation and the axle is reinstalled onto the car. The tire is installed and the car is removed from the jack stands.
- The car is road tested to ensure proper operation of the CV Boot and axle.
Have the CV boots checked for leaks or cracking when your car is being serviced during regular maintenance checks. If a CV boot is cracked or grease is leaking from the boot, have it changed by an expert technician.
What common signs indicate you may need to chnage the CV Boot?
- Axle grease leaking on the ground by the wheels or on the wheel rims
- Wheels bind during turns
- Metallic clinking sound during acceleration or braking
How vital is this service?
The CV boot carries a vital role in propelling your car. If the CV boot is cracked, or leaking and water or debris enter the CV joint, it may bind, seize, or break very soon after. Have the CV boot changed before additional damage happens. If additional CV joint damage happens, you may need to change the whole axle shaft instead of just the boot.