Summary
- Sound of knocking happens when the car is accelerating or braking.
- Faults in the suspension, brake, or steering systems create a knocking noise from the front wheel.
- A worn shock absorber can make a knocking noise when the car is driven over a bump.
- Best ways to diagnose the front wheel knocking noise problem are; to bounce the front of the car, wiggle the steering wheel, and shake the vehicle.
- The cost of fixing the knocking noise from the front wheel may vary according to car making process, model, and production year. It could be between $100 to $500 on average.
Introduction
The knocking sound from the front wheel of a car is a common problem for many drivers. It usually happens when the car accelerates or brakes, and various things can cause it. Therefore, it is important to determine the cause before going through the expense of fixing it.
What Causes the Sound of Knocking?
It is often difficult to diagnose the exact cause of a knocking sound coming from the front wheel of a car. It usually happens when the car is accelerating or braking and can be caused by any fault in the suspension system, brake system, or steering system.
Fault in Suspension System
Knocking noise from the front wheel can be caused by a worn shock absorber, loose or broken suspension springs, damaged struts/strut mounts, bad bushings, damaged control arms, broken sway bars, faulty ball joints, or bad axle.
Worn Shock Absorber
The shock absorber is a part of the suspension system that helps to reduce the impact of bumps on your car’s body. However, a worn shock absorber can make a knocking noise when the car is driven over a bump. This is because the rubber buffer inside the shock absorber has been worn away, and the metal shaft inside it is hitting against the metal casing. Shock absorbers are often overlooked in wear and tear because they’re not as visible as other parts, such as your tires.
Loose or Broken Suspension Springs
Loose or broken springs are among the most common causes of knocking noise from the front wheel. Several factors, including: may cause the noise
- The spring is loose and not properly attached to the vehicle
- The spring is broken and no longer able to support the weight of the vehicle
- The spring is damaged in some way, such as through corrosion or rusting
- There is an object in contact with the spring that has been displaced from its original position.
Damaged Strut/Strut Mount
A strut is a suspension component that keeps the car’s body level. It provides stability for the vehicle when driving at high speeds or turning sharply. It also helps to absorb bumps and other road conditions for a smoother ride. The struts are mounted to the vehicle’s suspension system with the help of metal brackets called strut mounts. The mounting point for struts varies depending on your vehicle type, but they are usually located near the front axle.
If you have ever heard your front wheel knocking against something, it could be an indication that either your struts are worn, loose, broken, or the mounts are damaged. It could happen from hitting potholes or curbs too hard, which can lead to damage to your struts and strut mounts. A strut can also be damaged by overloading with too much weight, not enough air pressure, or if it is poorly aligned or has worn bushings. Similarly, strut mounts can also be damaged, if you drive through deep water with your vehicle’s wheels submerged.
Bad Bushings
Bad bushings can also cause a knocking noise from the front wheel of your car. Bushings are rubber rings installed to help properly align the wheels and stabilize the suspension components by providing cushioning. The worn-out or broken bushings can cause a knocking sound because two or more metal components rub against each other without the bushing to buffer them. Therefore, it’s important to replace them as soon as possible.
Damaged Control Arms & Broken Stabilizer Bar
Control arms are a major component of the suspension system. They are attached to the steering knuckle and control the wheel’s movement. The control arm is a metal rod that connects to both sides of the vehicle’s suspension. The wheel rotates around a ball joint, which is attached to one end of the control arm, and connected to a stabilizer (sway) bar at its other end. This stabilizer bar reduces side-to-side motion to keep the car level during turns.
Similarly, the stabilizer bar gets damaged when the shocks get worn out, and the vehicle loses its balance and tilts to one side. Resultantly, the body weight of the vehicle, distributed among all parts of the suspension, gets increasingly shifted to the stabilizer bar and breaks apart.
Faulty Ball Joints
The ball joint is the most important part of the front suspension. It has to pivot and move in all directions, which is why it’s exposed to a lot of wear and tear. The ball joints are usually connected to the steering knuckle with two bolts that can be tightened or loosened with an Allen key. Ball joints connect the lower control arm to the spindle (or axle). They allow for the movement of the suspension, steering, and wheels.
The ball joint is responsible for transmitting torque from the steering column to the wheel hub, and it also absorbs some of the shock created by bumps in the road. The ball joint can get worn out or broken over time due to wear and tear or severe accidents. It will cause knocking sounds when driving on rough roads or turning your steering wheel.
Axle Problem
Axles are one of the most important parts of the vehicle. They are responsible for transferring power from the engine to the wheels. Therefore, axles are a vital component of any vehicle and will eventually wear out if not taken care of properly.
Many factors can cause axle problems:
- Worn-out axles: Axles can wear out over time due to excessive use or lack of lubrication. This leads to a knocking noise when turning corners or driving over bumps in the road.
- Damaged axle: An axle may become damaged if it has been hit by something, for example, if a car has been involved in an accident. If this is not repaired promptly, it can lead to serious issues with your car’s suspension and steering systems.
- Bent axle: A bent axle is usually caused by hitting something too hard (such as a curb) or driving off-road onto rough terrain.
Loosen Lug-Nuts
Loose lug nuts could cause a knocking noise from the front wheel. Lug nuts are the bolts that hold the wheel to the car. Therefore, it is important to tighten the lug nuts periodically, even if there are no signs of loosening.
Bad Tires
A knocking noise from the front wheel can be caused by a misaligned tire or a bad tire. If the tires are imbalanced, they will make a knocking noise when they spin. The most common cause of this knocking noise is that one of your tires is misaligned and rubbing against the suspension components.
Wheel Bearings
A wheel bearing is one of the most important parts of a car. It is the component that allows the wheel to spin freely and smoothly. If a wheel bearing fails, you will hear a knocking from the front, as it does not allow the wheel to spin freely.
Fault in Breaking System
Many components can cause this type of noise, including the brake caliper, the disc pad, or the rotor. For example, when the brake pad and the rotor rub together, it causes a knocking sound. Likewise, brake clippers cause a knocking sound when they rub against your rotor. This rubbing can be reduced by filing them down with a grinder or replacing them with new ones.
Fault in Steering Assembly
Bad Tie Rods: A tie rod is a metal rod that connects the front wheels to the steering system. It is responsible for turning the wheels left and right and keeping them in line. Tie rods are on either side of the vehicle, running parallel with the axle. They are connected to both wheels by way of ball joints. Unfortunately, as a car ages, it is not uncommon for one or more tie rods to wear out and make noise as they move back and forth within their sockets. When this happens, it may be time to replace the worn-out tie rod with a new part from your local auto parts store.
What are the Best Ways to Diagnose My Front Wheel’s Knocking Noise Problem?
Following are some of the diagnostic methods used to track the knocking noise from the front wheel:
- Bounce the Front of the Car
Open the hood and repeatedly press and release the car by putting pressure on its front fenders. While bouncing, keep examining the suspension parts that are visible to you. You will notice excessive knocking noise from the failed suspension components. Similarly, if the strut mount is broken, you will see excessive movement.
- Wiggle the Steering Wheel
This method can be used to point out the failed components of the steering system. Turn the steering wheel left and right vigorously. If there is any problem with any steering system component, it will make a knocking noise.
- Shake the Vehicle
Take two assistants to shake the car from both the driver’s and the passenger’s side and lie under the vehicle. Ask them to shake the car and carefully examine all the components defined to you in the above causes.
