TECH TIPS: REPLACING STRUTS AND SHOCKS

In this article, Arnott answers the question: when do you know it is time to replace the struts and shocks on your customer’s vehicle?

Arnott says air struts can last eight to ten years but, like other rubber components (like hoses, wipers and tyres), the rubber air bladder may get punctured or could begin to dry rot and develop tiny holes where the rubber air spring folds upon itself.
At first the air suspension compressor may continue to pump up the springs, but in time the holes will become too numerous or too large for the compressor to keep up and it will burn out and stop working from overuse.
It is here that Arnott says a coil spring conversion kit can be advantageous in a vehicle with air suspension.
The leading aftermarket suspension company says coil spring conversion kits can provide an aging vehicle with additional years of trouble-free suspension use because it replaces the aging air suspension’s air springs with coil steel springs and the older worn shocks with new custom-valved shocks designed to work with the steel springs.
It reports advantages include reduced maintenance and repair bills while being ideal for repairing a vehicle with multiple air suspension problems. It further states that a complete four-corner coil spring conversion may cost about the same as replacing one air strut at the dealership, but also notes that customers should not make the conversion if they tow trailers or heavy loads that could take advantage of the vehicle’s auto leveling functionality.
When it comes to deciding between recommending a remanufactured air strut or a new aftermarket one to a customer, Arnott says remanufactured OE struts support the active, adaptive or semi-active damping functionality of the vehicle, but have an unknown number of miles on the internal shock. On the other hand, new passive aftermarket struts have a brand new, zero-mile, custom-tuned damper without assistive damping, but they do adapt to the driver’s style.
While a remanufactured strut requires a core deposit and handling, the new shock does not and your customer may be eligible for a rebate if the used core part is returned. Both remanufactured and aftermarket new struts offer the luxury of air suspension that can auto level, smooth out bumps and provide a luxurious ride.
Arnott explains that you would recommend one versus the other based on the following factors:
a. Budget – it all comes down to budget and the age and miles on the vehicle, which could be over 15 years old.
b. Some older vehicle struts cannot be remanufactured because of the age of, and damage to, the strut.
c. If the customer talks about, and actually uses, the ability to adjust between comfort and sport damper modes – they may want a remanufactured semi-active strut.
d. Most drivers don’t ever touch or adjust their semi-active dampers. If the customer doesn’t use these modes or says they don’t find a difference – they may want the aftermarket passive new strut.
e. If the car has excessive miles on it the adaptive damping may not even be functional, so the new strut may be a better solution.
f. If the customer has true active damping such as that found on the Mercedes-Benz ABC suspensions, remanufactured or OE new struts are the only option. Coil conversion kits shouldn’t be recommended since they won’t have a control arm to stabilise lateral vehicle movement.

What are the main signs of air suspension problems?
Arnott says many consumers miss the early warning signs of an air suspension problem. Unfortunately for the customer, these symptoms only get worse – and more expensive – over time. Typical warning signs include:
• The Dashboard Warning Light – one of the obvious signs of an air suspension problem. Even if the light doesn’t stay on, the vehicle should be checked.
• Suspension Sagging – one of the first signs is when a car sags in one or more corners. Typically, this is due to the rubber air spring developing tiny cracks or holes because of dry rot or road debris. If a customer notes that their vehicle drops in height overnight or after they park, they most likely have leaks in their air spring or strut.
• Air Suspension Compressor constantly working – if there is damage to the air springs, the compressor will constantly be pumping air to keep the air bladders inflated. If the compressor is constantly running the system should be examined as soon as possible.
• Compressor not working at all – the air suspension system cannot function without the compressor. If the compressor does not come on at all that may be a sign that it was overworked and has burned out or it could be as simple as a fuse or relay problem.
• Compressor making noises – the owner may also notice abnormal noises during compressor operation such as loud clicking, whining or grinding. This could be a sign that the compressor has been overworked or could indicate that there is excess moisture in the system because the compressor’s dryer is saturated.

Once the compressor has been replaced, the rest of the system including the air springs and struts should be tested, says Arnott.
Other signs of suspension issues include:
• The vehicle bottoms out over bumps or rides roughly
• The vehicle nose dives when stopping (front end pitches forward)
• The vehicle pulls to one side or steering is difficult
• The vehicle continues to bounce after hitting a bump
• Uneven tyre tread wear
• The shock portion of the strut appears to be oily or damaged
If the customer complains about any of these symptoms, or if the vehicle is over five years old or has more than 50,000 miles, Arnott says you should inspect it for signs of air suspension damage. Replacing a leaking air spring with a quality aftermarket part may save the customer hundreds now, and thousands later, in additional repair bills.
Arnott says it offers an extensive line of affordable, high-quality air suspension products for more than 150 automotive and motorcycle applications.  

For more information, visit www.arnottindustries.com