If you hear a ‘creaking’ noise coming from the car’s chassis, accompanied by the steering wheel pulling to one side whilst driving, it could be a problem with the suspension bushings. Today, we’ll take a look at what you need to know about car bushings.
What is an automotive bushing?
In mechanical design, the connection of moving parts is a common requirement; however, relative motion between components can easily lead to friction and wear. To address this issue, flexible coupling solutions are widely adopted—not only do they effectively reduce wear, but they also make replacement more convenient and cost-effective should wear and damage occur later on. It is for this reason that industrial bushings have come into being.
In the automotive sector, bushings are elastic, flexible connecting components installed at the joints of moving parts such as the chassis suspension system and control arms. They are typically made from elastic materials such as rubber or polyurethane (or a composite structure combining a metal skeleton with an elastic material), and their core function is to replace rigid connections, thereby resolving the issue of friction and wear caused by the relative movement of components.
Put simply, they act as a ‘shock absorber and wear-resistant joint’ between chassis components.
What is the purpose of a bushing?
Chassis bushings play a crucial role in the construction of a vehicle’s chassis. Their primary function is to connect the chassis to the suspension system, preventing rigid connections, protecting metal components and absorbing shocks, thereby ensuring the vehicle’s stability and comfort whilst in motion. Chassis bushings must not only bear the vehicle’s weight and inertia but also cope with a variety of complex road conditions and driving scenarios. A high-performance chassis bushing can significantly enhance the vehicle’s ride quality, reduce tyre wear and suspension fatigue, and provide the driver with a more enjoyable driving experience.
Chassis bushings can be categorised into various types based on different classification criteria: these include front and rear axle bushings, tie rod bushings, control arm bushings, subframe bushings, hydraulic and non-hydraulic bushings, as well as metal and nylon bushings, and open and closed bushings. Although the classifications vary, the functions they perform are similar.
Points to note when replacing bushings
1. Selection of press-fit sleeves
When removing or pressing in components, select a sleeve of the appropriate size to ensure that the force is applied to the outer ring of the bushing, whilst other parts remain unloaded. Wear safety goggles and gloves when carrying out this work. The dimensional information provided in the Codic product manual can assist in selecting the correct sleeve.
2. Press-fit Force
To facilitate installation, remove any burrs from the inner bore prior to pressing and apply a small amount of lubricant (such as 4240 grease) to the inner bore and the initial section of the outer diameter. Ensure that the press-fit force is not too low; for bushings with an outer tube diameter of 40 mm, the press-fit force for metal outer tubes should generally exceed 6 kN, and for nylon outer tubes, it should exceed 20 kN, with values varying according to the diameter of the outer tube. If the pressing force is found to be too high or too low, check the condition of the inner bore and verify that the correct bushing has been selected.
3. Confirmation of Installation Position
During installation, ensure that the solid section is aligned with the horizontal direction of travel. If the product features an arrow, ensure that the arrow points in the horizontal direction of travel. Ensure that the pressing position is centred, with equal lengths protruding from both ends.
4. Stress Relief
Once installation is complete whilst the vehicle is raised off the ground, stress concentrations often develop in the chassis system. To resolve this, the vehicle must be lowered to the ground and the steering wheel centred. The fasteners should then be loosened to the specified torque, before being retightened to the standard torque to release the stress and allow the chassis to return to its original state. At this point, the vehicle is as though fitted with a brand-new pair of running shoes, ready to roam freely.
Whatsapp : 
Teléfono : 
Correo electrónico : 