First Line has highlighted the critical safety and performance role played by bushes in a vehicle’s steering and suspension system. In particular it says the design of bushes that are used in suspension arms can have a huge impact on the performance and service life of the complete unit.

First Line says it strictly follows the original equipment (OE) standard with its bush design and manufacturing, but points out other suppliers compromise and supply cheaper, non-OE standard bushes. These will often use a straight tube in their construction, rather than OE standard swaged tubes as used by First Line.

Swaged tube provides a greater bonding area for the rubber, which directly increases the longevity of the bush. It involves an extra manufacturing process and extra cost, but there are significant benefits in terms of longer life and less component failure. Also, if a replacement bush is poorly manufactured or manufactured to an inadequate specification, it is highly likely not to possess the correct shore hardness or deflection attributes that are required and will have an adverse effect on the handling, performance and ride quality of the vehicle.

As well as poor quality components, the First Line technical team also says that bushes often fail because of incorrect fitment, often due to a lack of the correct fitting equipment. They also point out that a wishbone should only have the fitting bolts tightened up when the vehicles wheels and axles are in the normal ride height position. Some garages do this when the wheels are in an unloaded ‘hanging’ position which puts a torque reaction on the wishbone bushes when the vehicle is taken off the service ramp, which will lead to premature failure of the wishbone and the centre of the wishbone bush will have been ripped away.

There is also an increasing trend to use stiffer polyurethane ‘competition’ style bushes for general road going cars. The instant benefit for the driver is an increased sensitivity in the vehicle’s handling characteristics. However, the harder compound used in these bushes will put extra load on to ancillary steering and suspension components that is contrary to the vehicle’s original design and will lead to premature failure of components such as anti-roll bars and wishbone bush mountings. 

For more information about First Line and Borg & Beck products please visit: www.firstline.co.uk