How to Troubleshoot Halfshaft With a Thumping Noise

Troubleshooting a halfshaft is relatively simple.

All front-wheel drive vehicles use halfshafts to transmit the power from the engine to the wheels. Sometimes called constant velocity (or CV) joints, your car's halfshafts are flexible and allow you to turn your front wheels while the engine is engaged. The rubber seals at each end of the halfshaft deteriorate over time, however, and eventually must be replaced. There are certain telltale signs which will help determine if it's time to fix your halfshafts.

Things You'll Need

• Lug wrench
• Tire jack
• Jack stand

Instructions

Troubleshooting While Driving

1. Roll down your windows and turn off anything in the car that makes noise, such as the radio or air conditioner.

2. Drive your car to a quiet street and accelerate to approximately 30 miles per hour while listening for clicking or thumping sounds.

3. Slow to an appropriate speed and make a sharp left turn, again listening for clicking or thumping sounds coming from the front wheel area. After straightening your steering wheel, make a sharp right turn. If either of the sharp turns results in clicking or thumping sounds that disappear when you are driving straight, proceed to Section Two.

Visually Inspect the Halfshafts

1. Park your car and set the brake. Chock the rear wheels and, using the lug wrench, loosen the lugs on the front left wheel.

2. Place the tire jack under the frame of the car and lift the vehicle enough so that you can remove the left wheel. After the wheel has been removed, place the jack stand under the frame and gently lower the tire jack enough so that your car is securely supported.

3. Locate the halfshaft by looking at the inside surface of the steering knuckle. You will see a steel shaft that runs between the knuckle and the transmission, with a rubber seal covering each end. Examine the seals at both ends of the shaft, but pay special attention to the flexible end near the wheel. Ascertain whether the seal has torn and note if you see a significant amount of axle grease on the hub area and inside surface of the tire. Once you have completed inspecting the left wheel, replace the tire and lower the vehicle to the ground. Repeat the same process with the opposite wheel. Arrange to repair any damaged seals.

Tips & Warnings

• A torn halfshaft seal will allow the lubricating grease to escape and will eventually result in a damaged CV joint. If your car is clicking or thumping during turns and the seals are torn, the halfshaft is severely damaged and must be replaced.

• Always use a jack stand any time you plan to work under the car.

• A damaged halfshaft, if left unrepaired, can be an extremely dangerous condition. Eventually the shaft will break during operation, resulting in a catastrophic and sudden loss of power to one side of the car.

References

• AA1 Car: Constant Velocity Joints: Service & Repair