Thumping Sounds While Driving Over Sharp Bumps: Reasons & Solutions

Unfortunately, we don’t always find ourselves driving over perfectly smooth, freshly paved roads. And while rough roads may cause some issues with your vehicle, they can also help diagnose potential issues. A thumping noise while driving over bumps can be startling for a driver, especially if the same noise did not manifest itself on flat roads. If you notice a thumping noise while driving over a bump, you should have a mechanic inspect your vehicle.

The suspension system and brake system in your vehicle are made up of many components that adjust when driving over rough terrain to ensure a comfortable ride. When these components fail, they may make clunking or thumping noises to alert you that something is wrong. When suspension components such as tie rod end and ball joints fail, they typically make a thumping noise all the time, not just over bumps, and brake system failure and cause squeaking, clunking, and thumping noise. This is that thumping sound that you should pay attention to when you are driving:

Here are reasons for the thumping sounds while driving over bumps that your car may have.

Worn Out Or Damaged Shocks And Struts

In good condition, shocks and struts help your car handle whatever the road throws at it: bumps, debris, sudden stops, swerving, potholes, wind gusts, or sharp turns. They maintain optimal tire contact with the road by controlling the side-to-side, front-to-back, and up-and-down shifts of the car’s weight.

Shocks and struts are heavy-duty components. Over the course of 50,000 miles, they can complete 75 million cycles. They can move up and down 1,500 to 1,900 times per mile, even on well-paved roads. They work in tandem with the brakes, steering, suspension, tires, and electronic safety systems — anti-lock brakes, stability control, and crash avoidance systems — to keep a vehicle on the road safely. They:

• Maintain tire contact with the road by preventing excessive up and down movement.
• As you accelerate, stop, and turn, they can help maintain stability.
• Increase ride comfort by absorbing jolts and bumpiness caused by uneven road surfaces.
• Control the body movement of a vehicle (side-to-side roll, bouncing).
• Help the tread wear evenly for longer tire life.

Contrary to popular belief, they do not aid in the support of the vehicle’s weight or any loads. That is done by the springs. However, worn-out shocks or struts make the springs and other suspension components work harder. Without the control provided by a good shock or strut, these other parts are overworked, resulting in fatigue and premature wear and that thumping sound in your car when driving over bumps.

Bad Sway Bar Link

The sway bar is a stabilizer bar that connects the wheels on opposite sides of the vehicle. The sway bar is in charge of controlling “body roll” by distributing your vehicle’s weight to both sides of the suspension. When your vehicle enters a turn, the sway bar maintains vehicle level by minimizing body roll by transferring vehicle weight to the outside wheels. It also maintains solid contact with the road surface by compressing the suspension components on the inside wheels.

Because sway bar links are responsible for transferring the force of motion from the wheels to the sway bar and to the rest of the suspension system, if a sway bar end link is damaged, the controllability of your vehicle and the safety of your passengers are at risk. While some sway bar links have bushing that can be replaced, other sway bar links require replacements upon wearing out. 

Clunks and squeaks and thumping when driving over bumps are warning signs of a broken or faulty sway bar link. Over-steering and excessive lean through turns are also symptoms of worn sway bar links, but they can also indicate larger issues with your vehicle’s suspension system. Do not ignore symptoms of faulty sway bar links or other suspension components. If these are not repaired or replaced, they can grow into larger problems and more expensive repairs.

Worn Control Arm Bushings

Bushings are cushions made of rubber, polyurethane (often shortened to “poly” or “urethane”), or other materials. They are installed on car suspension and steering joints to absorb road bumps, control joint movement, and reduce noise and vibration. Bushings are typically thick, rubbery washers through which suspension components — or the bolts that connect them — pass.

Bushings allow for more movement as they wear. On rough roads, the driver may feel a shimmy from the front of the vehicle or hear clunking or rattling noises when turning the wheel or braking hard, or a thumping sound when going over a bumpy road. Drivers may also encounter poor handling or jerky steering. Failure of rear suspension bushings may be more difficult to detect because they are not involved with the steering system and are less affected by cornering. When bushings wear, they put more strain on the joints and connected parts, similar to how cartilage protects knees and elbows. Worn bushings, like bone-on-bone contact, can allow metal-on-metal contact. Worn control arm bushings can cause the front end of the vehicle to slip out of alignment and cause tire problems.

Loose Brake Caliper

Calipers, or brake calipers, are some of the most important components of modern disc brake systems. They work with the brake pads and rotors, as well as the rest of the hydraulic system, to slow and stop the vehicle. When you press the brake pedal, the brake fluid pressure is pushed through the master cylinder to the caliper, which extends the piston and presses the brake pads against the rotors to slow the car down.

Whenever you notice any sort of high-pitched noises, sudden thumping when driving over bumps, or impact sounds when you apply the brakes, it is a sign of a loose caliper. Even though, there are other possible outcomes, such as calipers sticking or binding. However, a brake caliper in this condition will be unable to properly stop the vehicle, potentially resulting in premature brake wear. As a result, whenever you brake, you should always be on the lookout for any unusual sounds coming from the wheels. A backing plate is attached to the back of each brake. When the plate is bent inward, it rubs against the rotor or caliper, causing a clicking sound. It could be a metallic rubbing or squealing noise.

A vehicle that makes a thumping noise while going over a bump may reveal an issue mainly in the suspension system or it can be in the brake system. Not only do these systems provide a comfortable ride but it plays a critical role in the safety of the vehicle, especially when cornering and braking. If you notice a noise while going over bumps, you should have it inspected to make sure that they are working properly.