Wheels, Steering & Suspension
What Does the Knocking Sound Like?
A knocking or clunking noise when driving over speed bumps, potholes, or rough ground is one of the most common suspension complaints. The sound usually comes from underneath the car and can range from a soft thud to a loud clunk or knock. It may happen every time you go over a bump, or only on sharper impacts.
Some drivers also notice the steering feeling loose or vague, the car bouncing more than usual after a bump, or a rattling sound on uneven roads. These are all signs that something in the suspension or steering system needs attention.
What Is Causing the Knocking?
There are several parts underneath your car that can cause a knocking noise when going over bumps. Below are the most common causes. Only a proper inspection can confirm exactly what is wrong with your car.
Worn Shock Absorbers or Struts
Shock absorbers (also called dampers) control how your car responds to bumps and dips in the road. When they wear out, they can knock or clunk as they bottom out over bumps, and the car will bounce or float more than it should after going over uneven ground. Our suspension repair service covers shock absorber inspection and replacement.
Worn or Broken Suspension Bushes
Suspension bushes are small rubber or polyurethane cushions that sit at the joints of your suspension components. They absorb vibration and reduce noise. Over time they crack, harden, or collapse, causing metal parts to knock against each other when the suspension moves.
Loose or Worn Anti-Roll Bar Drop Links
The anti-roll bar (also called a stabiliser bar) helps keep the car level when cornering. It is connected to the suspension by drop links. These are a common cause of knocking over bumps, especially at low speeds, and are relatively straightforward to replace.
Worn Ball Joints
Ball joints connect the steering knuckle to the suspension arms and allow the wheel to move up and down and side to side. When they wear out, they develop play and can knock loudly over bumps. Worn ball joints are a safety concern as they can affect steering control.
Damaged or Worn CV Joint
Constant velocity (CV) joints transfer power from the engine to the wheels while allowing the suspension to move. A worn CV joint can cause knocking or clunking when going over bumps, though it more commonly produces a clicking sound when turning.
Loose Heat Shield or Exhaust
Sometimes the knocking sound has a simpler cause. Heat shields are thin metal covers that protect parts of the car from exhaust heat. They can come loose over time and rattle or knock when the car goes over bumps. A loose section of exhaust can do the same.
Worn Top Mounts
Top mounts (also called strut mounts) sit at the top of the shock absorber assembly and connect it to the car body. When they wear, they can produce a knocking sound over bumps, along with a grinding or creaking feeling through the steering.
Wheels, Steering & Suspension
Is It Safe to Drive?
| What you are experiencing | Is it safe to drive? | What to do |
|---|---|---|
| Occasional light knocking over large bumps only | Use caution | Book an inspection soon. The problem is likely to get worse over time. |
| Regular knocking over most bumps | Not recommended | Get it checked within a few days. Worn suspension affects handling. |
| Knocking plus steering feeling loose or wandering | Do not drive | Could be a worn ball joint. This affects your ability to control the car. |
| Knocking plus the car pulling to one side | Not recommended | Have it inspected as soon as possible. |
| Knocking plus a clunking sound when turning | Not recommended | Could be a CV joint or ball joint issue. Book an inspection promptly. |
| Knocking plus excessive bouncing after bumps | Not recommended | Likely worn shock absorbers. Stopping distances and control may be affected. |
Wheels, Steering & Suspension
What Should You Do?
1. Do not put it off. Suspension and steering components wear gradually, which means the knocking may not seem urgent at first. However, worn parts affect how your car handles and how safely it stops, especially in an emergency.
2. Avoid roads with lots of potholes or rough ground where possible. This will not fix the problem, but it reduces the stress on already worn components until you can get the car looked at.
3. Pay attention to any changes in steering. If the steering starts to feel vague, heavy, or pulls to one side, treat this as urgent. These are signs that a safety-critical component may be failing.
4. Call First Auto Centre. Give us a call on 020 4539 0131 and describe what you are hearing and when it happens. Our team can advise you and get your car booked in for a suspension inspection at our East Ham garage.
5. Get a proper diagnosis. Several different components can cause a knocking sound, and they all feel similar from the driver’s seat. Our mechanics will use car diagnostics alongside a physical check of your suspension, steering, and related components to pinpoint exactly what needs attention.
Hearing a Knock Over Every Bump?
Let Us Take a Look.
Suspension problems are easy to put off, but they affect how safely your car handles and stops. Bring your car to First Auto Centre in East Ham and our experienced team will carry out a thorough suspension inspection and give you a straight, honest answer.
Call us on 020 4539 0131 or visit us at 1 Lawrence Road, East Ham, London, E6 1JN.
We are open Monday to Saturday, 09:00 to 18:00.
This page is for general guidance only. Only a physical inspection can properly diagnose a suspension or steering issue. If your car feels unsafe to drive, call us before driving further.
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Your Questions
FAQs
It depends on the cause. Worn shock absorbers, ball joints, and suspension bushes can all result in an MOT failure if they are found to be below the required standard during the test. If your car is due an MOT and you are noticing a knocking noise, it is worth having the suspension checked beforehand.
This depends on what is causing the knock. A loose heat shield is unlikely to cause an immediate safety issue. A worn ball joint, on the other hand, can fail suddenly and affect your ability to steer or control the car. It is always safer to get the noise investigated promptly rather than wait.
Low-speed knocking over bumps is very common with worn anti-roll bar drop links or suspension bushes. At higher speeds on smoother roads, these faults are less noticeable, which is why many drivers only become aware of them in town or on residential streets with speed bumps.
Yes. Hitting a deep pothole at speed can damage shock absorbers, crack or displace suspension bushes, bend anti-roll bar drop links, and in serious cases damage a wheel or tyre. If your car developed a knocking noise after hitting a pothole, have it inspected as soon as possible.
The cost varies depending on which component needs replacing. Anti-roll bar drop links and suspension bushes are generally at the more affordable end. Shock absorbers and ball joints can cost more depending on the car. At First Auto Centre, we give you a clear, honest quote before any work begins.
No. Suspension and steering components do not repair themselves. The noise will usually get worse over time as the worn part deteriorates further. Catching the problem early generally means a simpler and less expensive repair.
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Contact Us
- info@firstautocentre.co.uk
- 1 Lawrence Road, Newham, London, E6 1JN
- Mon-Sat: 09:00 - 18:00
- Sunday: Closed
