On the Volvo S40, control arm problems mainly arise from wear to the bushes and ball joints, not the metal arm itself. The result is knocking noises, unstable handling and uneven tyre wear. If you act early, you can prevent more serious damage and keep repair costs down. Read on to find out how to recognise wear and what you can do about it.
What exactly wears on the control arms?
The control arms of the Volvo S40 are themselves robustly built. Wear almost always occurs in the suspension components. These parts are attached to the arm. This means that problems do not stem from cracks or deformation of the metal, but from deterioration of flexible and moving components.
The main wear items are the rubber bushes and ball joints. These connections ensure smooth movement of the suspension, but age due to load, vibrations and moisture. Over time, the rubber hardens or cracks, creating play. The ball joints can also become loose or damaged due to lack of lubrication.
Another vulnerable point is the ball joint, which is often mounted fixed to the control arm. This part is subjected to the same loads as the control arm and can also fail shortly after the arm. Mechanics therefore recommend checking the ball joint at the same time as replacing the control arm and replacing it immediately if necessary.
Symptoms of worn control arms on a Volvo S40
Wear on the control arms often starts subtly. The first signs are sometimes barely noticeable. They gradually become clearer. By responding early, you prevent small issues from developing into major suspension defects.
Recognisable symptoms include:
- Knocking or thudding noises when driving over speed bumps, raised junctions or potholes in the road.
- Unsettled steering, where the car tracks less straight ahead or drifts without you doing anything to cause it.
- Uneven tyre wear, often on the inner or outer edge of the tyre.
- Noticeable play in the suspension when the car is on a ramp or lift and you pull or push on the wheel.
- Pulling behaviour when braking or steering, especially in bends or during changes in speed.
If you notice one or more of these signs, it is wise to have the suspension checked. A mechanic can determine, based on play, noise and visual inspection, whether the control arms or adjacent components are worn.
How often should control arms be replaced on a Volvo S40?
There is no fixed replacement interval for control arms, because service life strongly depends on driving style, road surface and maintenance. In practice, control arms on the Volvo S40 generally start needing attention somewhere between 100,000 and 150,000 kilometres, but this can vary.
Factors that accelerate wear include frequently driving on poor road surfaces, taking sharp bends at high speed and insufficiently lubricated ball joints. Exposure to road salt in winter can also cause the bushes to deteriorate more quickly. Drivers who often drive on rough paved roads with many irregularities will notice problems sooner than someone who mainly drives on modern motorways.
When replacing, it is often sensible to tackle both left and right at the same time, especially if both sides show similar wear. This ensures balanced handling and prevents the other wheel from developing problems shortly after repairs on one side.
Also check adjacent components
If you have the control arms replaced, it is a good idea to have the ball joints, bushes, wheel bearings and ABS sensors inspected at the same time. These parts are easily accessible during fitting and may also show wear. Replacing them in one go prevents you from having to return to the workshop shortly after the repair.
DIY control arm replacement on a Volvo S40
Replacing control arms yourself is technically possible, but requires tools, knowledge and experience. The work involves disconnecting the wheel suspension, removing bolts and joints under tension, and correctly tightening the new parts. For anyone who regularly works on cars themselves and has access to a lift or axle stands, it is achievable.
Even so, there are reasons to leave the job to a garage. The main one is that a wheel alignment is required after replacing control arms. Without correct alignment, the car will not track straight and you will get uneven tyre wear. A garage has the alignment equipment and can immediately check whether the new parts are correctly fitted and the wheel alignment is correct.
If you still decide to do it yourself, bear in mind the following steps:
- Support the car safely on axle stands and remove the wheel.
- Undo the ball joint nut and disconnect it from the wheel hub.
- Remove the bolts that connect the control arm to the subframe.
- Replace the control arm and fit the new parts in reverse order.
- Tighten all bolts to the correct torque according to Volvo’s specifications.
- Have the car aligned at a garage immediately afterwards.
Note that some control arms are supplied with pre-installed bushes and joints, whereas for other versions these parts have to be ordered and fitted separately. Check this beforehand to avoid surprises.
‘ That sometimes makes the short-term saving more expensive in the long term. ’
Choose quality parts for a longer service life
For the Volvo S40, both genuine and aftermarket control arms are available. Genuine Volvo parts usually offer the most predictable quality and service life, but they are more expensive. Aftermarket parts are cheaper, but their service life can be less predictable.
Mechanics and specialists advise choosing brands with a reliable reputation. Cheap alternatives may develop play or creaking noises more quickly, meaning the control arms have to be replaced again sooner. That sometimes makes the short-term saving more expensive in the long term.
If in doubt, it is best to seek advice from a Volvo specialist or a garage with extensive experience of the S40. They can indicate which brands perform well in practice and which versions are best avoided.
Alignment after replacement is essential
After replacing the control arms, a four-wheel alignment is required. This process ensures that the wheels are set at the correct angles and that the car drives straight ahead without pulling. Without alignment, you will get uneven tyre wear and the steering wheel may sit crooked.
The cost of an alignment is limited compared with a new set of tyres or further suspension damage. Most garages offer this directly as part of the fitting work. When booking an appointment, explicitly ask whether alignment is included in the price, so you don’t get any unwelcome surprises.
Preventive maintenance limits wear
Although wear on control arms is inevitable, you can extend their service life through conscious driving and regular checks. Avoid hard impacts with kerbs, deep potholes and sharp obstacles wherever possible. Regularly inspecting the suspension also helps to detect early signs of wear.
During scheduled maintenance, have the mechanic check for play in the wheel suspension. This is a quick check that takes little time but can reveal problems at an early stage. Drivers who regularly travel on poor road surfaces should have the suspension inspected more often. Standard service intervals do not stipulate this.
‘ “there is always more to discover.” ’
Discover more about the Volvo S40 and maintenance
Control arm wear is just one aspect of maintaining the Volvo S40. On the Carnews website you will find extensive information about common problems, maintenance advice and practical tips for this and other models. Whether you want to know more about points to watch when buying, frequently occurring problems or specific repairs, there is always more to discover. Take a look and stay up to date with everything you need to know as a Volvo driver.
Frequently asked questions
Typical symptoms of worn control arms on a Volvo S40 are knocking or thudding noises when driving over speed bumps and other irregularities. You may notice that the car no longer tracks straight as precisely, leading to unsettled or floaty steering behaviour. Uneven or irregular tyre wear often develops as well. At a more advanced stage, the car can start to pull when braking or steering.
Wear on the control arms (especially bushes and ball joints) can cause unsettled and unpredictable handling, where the car no longer tracks as straight and becomes more sensitive to ruts in the road. This increases braking distance and can reduce stability when swerving or making emergency steering manoeuvres, which directly affects safety. It also often leads to irregular tyre wear and reduced grip. At an advanced stage, extra play in the suspension on a Volvo S40 can cause the car to pull unexpectedly when braking or steering.
Under normal use, the control arms (especially the bushes and ball joints) of a Volvo S40 roughly last between 100,000 and 200,000 km, but driving style and road quality can greatly shorten or extend that. Avoid frequently driving hard over speed bumps, kerbs and potholes, and protect the suspension by steering smoothly and not braking aggressively. Have the suspension periodically checked for play and cracks in the bushes so that you tackle wear at an early stage. Use quality parts (preferably OEM or premium brands) and have the car aligned after replacement to prevent extra stress and tyre wear.
You can replace the control arms yourself if you have mechanical experience, good tools and a lift/jack; in that case you will roughly pay €150–€300 for parts (budget to premium brand, for both front sides). If you have the work done at an independent garage, the total cost is usually around €350–€700 for both control arms including alignment, depending on labour rates and any extras (bolt kits, ball joints). At a Volvo specialist or dealer with genuine parts you should expect around €600–€1,000 for both sides. In terms of parts choice, you can go from cheap aftermarket arms to OEM quality; the former are cheaper but often do not last as long as branded components.
On the Volvo S40, the main weak points of the control arms are the rubber bushes and the ball joints, rather than the arm itself. Worn bushes or ball joints often cause knocking or thudding noises, unsettled steering and irregular tyre wear. In practice, specialists advise that when wear is detected, the ball joint and surrounding suspension components should also be checked or replaced. After replacement, an alignment is important to prevent extra tyre wear and pulling to one side.