* Ball Joints: Worn ball joints are a common cause of knocking, especially over bumps or when turning at low speeds. They connect the control arms to the steering knuckles and allow for smooth suspension movement. A knocking sound often indicates play or excessive wear.
* Tie Rod Ends: Similar to ball joints, worn tie rod ends connect the steering rack to the wheels. Loose or worn tie rod ends will create a knocking or clicking sound, particularly during turning.
* Sway Bar Bushings/Links: These components help control body roll. Worn bushings or links can produce a knocking sound, especially when going over bumps or uneven surfaces.
* Control Arm Bushings: Worn control arm bushings allow for excessive movement in the suspension, leading to knocking.
* Rack and Pinion: Problems with the rack and pinion steering system itself can cause knocking, but this is less common and usually accompanied by other steering issues.
* Wheel Bearings: While more likely to produce a grinding or humming sound, severely worn wheel bearings can sometimes manifest as a knocking noise at low speeds, especially when turning.
* Brake Components: While less likely to be the *primary* source of a knocking sound, worn brake components (calipers, pads, rotors) *could* contribute to a noise, especially if the pads are hitting something beyond normal wear.
To diagnose the problem:
It's best to have a qualified mechanic inspect your vehicle. However, you can try these things to help pinpoint the source:
* Visual Inspection: Carefully examine the front suspension components for any obvious signs of damage, looseness, or wear. Look at the ball joints, tie rod ends, sway bar links, and control arm bushings. Check for any obvious leaks.
* Listen Carefully: Try to pinpoint where the noise is coming from – is it more pronounced when turning left, right, or going over bumps? This can help narrow down the possibilities.
* Jack Up the Car (Safely): With the car safely jacked up and secured on jack stands, try gently moving the wheels and feeling for excessive play in the suspension components. Safety is paramount when working under a car.
Do not attempt to drive the car extensively with a persistent knocking sound. This could cause further damage. Get it professionally inspected as soon as possible to avoid potentially dangerous and costly repairs.
