A member of the public recently came to us with a problem with his Renault Megane.The steering rack had been replaced three times but the there was still a knocking noise during driving. Here we’ll take look at the reason for this and how to prevent it.
The steering rack had been fixed with the bracket in the image below which shows an aluminium rest, a rubber damper and a steel clamp. You can clearly see the steel clamp was over-stretched and giving the rack too much play in the rubber which caused the noise.
Browising the image below it looks like the mechanic had tightened the left screw first and then the right one, instead of tightening each one bit by bit. On the right of picture you can see some grooves showing where the mechanic has over-tightened the screw.
In the picture below you can see the damage and the deformation of the rubber damper caused by this over-tightening, which resulted in the knocking noise.
If you look closely at the image below you can see a small dent. If this is left over a long period of time it could result in a broken clamp and the risk of a complete failure of the steering. In this case the customer would need to change both of the brackets, all bolts and screws and the two rubber dampers. In addition, too long a screw had been used to fix the aluminum bracket.
This has caused the crack on the bottom of the following image.
If the screw is too long, the bracket is not fixed to the chassis which leads to excessive noise and could be potentially dangerous. The stripped thread on the left of the picture above shows that too high a torque has been used. You should not re-tap the original thread as this does not give you a strong enough fastening and could lead to failure.
Lesson learned: be on the safe side and exchange faulty and damaged parts. Always follow the manufacturer’s recommendations of how to fit parts.