KYB Answers Suspension Questions Commonly Asked By Mechanics

5 January 2017

The innovation and technological advances of vehicles in the 21st century has changed the way we drive, putting even more importance on the continual improvement of shock absorber performance.

With 81 years in the suspension industry KYB has stood the test of time, developing high quality OE and aftermarket suspension products that are vehicle specific and purpose built to meet the unique needs of every make and model. The evolution of the KYB range and high quality product is testament to the expertise of our global engineers and relationships with national mechanic customers, which has given us insight from the workshop level on how to make the job more efficient and easier. To share our insights, we have answered five questions commonly asked by mechanics:

How does a Shock Absorber work?

When a vehicle is being driven, its shock absorbers are constantly hard at work. Maintaining the handling and stability of the vehicle, the shock absorber overcomes road surface irregularities by compressing and extending as the tyre comes into contact with the road. The motion of compression and extension forces fluid through a series of speed sensitive valves, (the piston rod speed determines the appropriate valve) which in turn restricts the oil flow and controls the vehicular movement. Heat is then generated in the oil as a result of the friction. As it passes through the valves and into the outer body of the shock absorber, it is cooled with air passing over it while the vehicle is being driven. The nitrogen gas in the shock absorber also puts pressure on the hydraulic oil making the shock absorber more reactive to movement. This delays the onset of fading and foaming and makes it a higher performing product.

Do worn Shock Absorbers affect driving stability? How important are Shock Absorbers when braking and accelerating?

Yes, worn shock absorbers have a significant effect on a vehicle’s ability to accelerate and brake. This is because the purpose of a shock absorber is to control vehicle movement, keeping the wheels planted on the ground. As with any wear and tear, the performance of a shock absorber is compromised when worn out. This is evident in a number of ways:

  1. The ability to keep the vehicle stable is diminished, reducing driver control.
  2. A greater braking distance is required before coming to a complete stop.
  3. The vehicle may nose dive and/or the rear may lift, reducing stability and tyre to road contact.
  4. During hard acceleration the rear of the vehicle may dip while the front rises, then impacting the steering control.
  5. In extreme conditions worn shock absorbers can cause tyres to lose traction as the vehicle weights and unweights the tyres through excessive body movement and lack of dampening control. This loss of traction then has the potential to cause an accident.

When replacing the struts in my vehicle should l also replace the bump stops?

Replacing struts in a vehicle can be very time intensive as it requires the entire strut to be removed and disassembled. For this reason it’s always best to replace bump stops at the same time as struts, at the very least inspect them to avoid pulling it all apart again a few months down the track.

What is the purpose of an ‘Internal Top-Out Bump-Stop’ commonly found in the front struts of late model Ford Falcon and Territory vehicles?

The purpose of an ‘Internal Top-Out Bump Stop’ is to prevent full extension of the piston rod while driving. Limiting the travel prevents metal-to-metal contact. More importantly it helps to control the vehicle, reduce body roll and keep the vehicle flatter during cornering. It also reduces vehicle pitching under hard  acceleration and braking instances.

What is the function of a Steering Damper?

As the name suggests, a steering damper acts to dampen and control the vehicle when the tyre makes contact with a hole or rut on the road. It also helps the vehicle to drive and steer in a straight line, preventing it from following channels and curves in the road surface. While a new steering damper reduces driver fatigue and makes driving safer, a faulty one can force the steering wheel from the driver’s hands   when contact is made with a bump in the road.

To learn more about KYB Shock Absorbers go to (For Australian customers)