The steering rack bushes are small rubber or polyurethane mounts that hold the steering rack in place against the subframe of your car. As these mounts deteriorate, the way that your car steers can change in obvious ways.
What Bushes Actually Do
The bushes are located between the steering rack housing and the steering rack mountings on the car’s subframe. They absorb the loads put on the rack during use, including vibration, ensuring that the rack remains stationary when not in use. If the bushes fail, the whole of the rack can move about when using the steering, including when stationary, which can cause poor control of the car and wear on other components.
How Rubber Hardens Over Time
Rubber naturally deteriorates as it gets older and is subjected to high temperatures. The rubber will become harder and it will begin to develop cracks and deterioration. Eventually this leads to the rubber’s compression (when it is pressed into the rack housing) to ‘set’ in the compressed state, meaning that the rubber will no longer return to its original dimensions. As the bush wears, small gaps will begin to appear between the surface of the bush and the inner surface of the rack housing. See also Car Steering Rack.
Road Contamination Speeds Things Up
Oil, dirt and salt from the roads are amongst the worst contaminants for rubber. And when you are stationary for long periods of time the steering column can be subject to repeated small inputs which, in conjunction with the odd bump and scrape when pulling away from junctions, can rapidly cause compression set in the bushes. Urban stop-start traffic is particularly bad for this reason.
Spotting the Symptoms
A worn steering rack can make a dull clunking sound over speed bumps and pot holes as the steering rack hits the steering rack mounting bracket. Also at higher speeds the car may pull to one side and require constant correction to be driving straight. If you grab hold of the steering wheel and give it a good shake from side to side with the engine off and you can see the steering rack moving from side to side then the bushes are worn. In extreme cases worn bushes can cause failure of the steering components for your car’s MOT inspection. So it’s best to get them sorted before your MOT is due to try and avoid any extra stress on the steering rack. Early detection and repair of worn bushes will mean a simple repair rather than a costly repair for a worn out steering rack.
Catching bush wear early is important, as even slight wear can be easily rectified before further damage is caused, potentially leading to more costly repair and stress on the steering rack itself.
