What is a Link Shaft?
So, today, we will talk about one particular shaft, and this is the upper suspension arm link shaft.
This part is the one that links the upper suspension arm to the body of the car.
It is a part of the steering suspension that turns up and down as the wheels move.
As you can see in the left image you have the upper suspension arm and the link shaft disassembled.
The link shaft has the bushing detached from the link shaft. That single link shaft has bushings on both ends. those will serve as the nuts that will be tightened to secure the upper suspension arm.
As the car moves, the wheels bump up and down the link shaft turns up and down too. A time comes that the thread between the link shaft bushing and nut and the link shaft thread will be worn and it will not be fitted to each other.
When the threads are worn the link shaft will loosely move and produces a sound you will never believe that comes from that part.
In different brands, the bushing is a rubber, other than the threaded which serves as a nut. You can see in the image below.
When that rubber bushing is deformed due to time and use of the car it should be replaced.
The symptom is just a sound. You will usually notice it when you drive on a rough road. When the car bounces up and down particularly the front wheels, you will hear a loud knock sound under your car. This is more obvious in the kind of shaft above, which the bushing is the nut itself.
This is not so much a consequential accident but when the defect is severe maybe you cannot tolerate it as you go along your way because it’s noisy and will hear that even in a smooth road.
Bring your car to the shop and be inspected. When the mechanic will tell you that it should be replaced, it should be replaced. Unless you enjoy hearing the noise as you go every day on your journey.
It is the upper suspension arm that moves up and down as the wheels bump along the road.
The link shaft holds an important role in the suspension steering system. The link shaft rod, the bushing. They may be a rubber or steel they both have a time limit of use. When that time comes they will complain and you will hear that through a sound.
When you can still ignore it then no problem but if you can no longer ignore find a time for them to be replaced.