What the weather can reveal and why we assess both control arm bushes
In this article
Which vehicles this advice applies to
Vehicles with rubber-to-metal bushes in the suspension control arms. The symptoms, number of bushes and repair method depend on the particular suspension design.
What to do now
If controllability also deteriorates or obvious damage occurs, stop safely and seek advice on the next steps. Quietening in different weather is not a reason to ignore these accompanying problems.
What the symptom may mean
A creak occurs as you drive over a bump or the body moves up and down, but is barely audible in other conditions. At J&S SERVIS, we have encountered cases where the noise is more pronounced in dry weather. A noise that begins or becomes louder in low temperatures or frost is a separate situation. In damp conditions, the creaking may become much quieter or temporarily disappear.
Changes in the noise with the weather help when looking for the cause, but do not identify a faulty part on their own. Quietening after rain does not confirm that the cause has been removed.
Creaking and mechanical damage are assessed separately
A suspension bush is a flexible mounting that allows the specified movement of components and reduces the transmission of vibration. Some noises can arise from friction between parts of its construction. On a particular version of the Audi A3 front mounting, creaking can occur in cold conditions without affecting its function or service life. This cannot, however, be applied to every creaking or damaged bush.A suspension bush is a flexible mounting that allows the specified movement of components and reduces the transmission of vibrations. Some noises may be caused by parts of its construction rubbing against each other. Squeaking alone does not establish the condition of the bush; it is necessary to assess whether the noise occurs without impairing its function or is caused by damage.
A similar-sounding noise cannot be labelled harmless or taken as evidence that replacement is necessary without an inspection. Another part of the suspension may also be the source. Before repair, we therefore locate the source of the sound precisely and assess the condition of the relevant components separately.
Dry weather, frost and damp conditions are assessed separately
| Observed symptom | What needs to be distinguished |
|---|---|
| Creaking in dry weather | Note whether the sound changes in damp conditions during the same normal vehicle movement. A link with dry weather alone does not identify a particular component. |
| Creaking in cold or freezing conditions | Describe the temperature and circumstances. A cold-weather symptom may develop differently from creaking in warm, dry conditions. |
| Quietening in damp conditions | A temporary reduction or disappearance of the sound is diagnostic information; it does not confirm a repair or the mechanical condition of the bush. |
| Creaking accompanied by a knock or a change in steering | Play, damage and vehicle controllability must be assessed as well as the noise. |
We check both bushes in the control arm
If a control arm has two bushes, both need to be assessed. Each has its own position and contributes to locating the arm. When looking for the cause, we therefore do not limit the inspection to the bush from which the noise appears to come. The rubber, its bond to the metal and the movement of the mounting are checked under conditions appropriate to that design.
Surface appearance alone does not provide a complete picture of how the bush behaves under load. The conclusion should be based on inspection on the vehicle and, where necessary, examination of the removed component.
Why we recommend replacing both bushes
For a control arm with two separately replaceable bushes, J&S SERVIS recommends replacing both bushes in that arm when repairing a worn mounting. The repair then covers both of its flexible mounting points. The condition of the second bush must be assessed even if it is not creaking during the inspection.
This is a recommended workshop approach for the appropriate control arm design. The actual repair must be determined by the findings, the condition of the arm itself and the vehicle documentation. Creaking alone is therefore not an automatic reason to replace both bushes on every vehicle.
What to tell the workshop
For a quicker discussion, have the VIN, current mileage and a brief description of the requested work or fault ready. We confirm the appointment and scope of work by agreement.
What to tell the workshop
Report whether the sound occurs over a speed bump, smaller uneven surfaces, while turning or during another normal vehicle movement. Add whether it changes in dry, damp or freezing conditions and whether it is accompanied by a knock, altered steering or instability. Do not try to provoke the fault through unsafe tests.
How the cause is checked
Correct installation matters
Replacement requires the correct part version, its correct installation position and the manufacturer's procedure. On the relevant rubber-to-metal bushes, tightening in the wrong position can place unwanted preload on the rubber and cause premature damage. Simply fitting a new bush into the arm is therefore not enough.
Depending on the work carried out, the need for a wheel alignment check is also assessed. After repair, it is important to check the result under the conditions in which the original noise occurred, where circumstances allow.