Solid Tactics for Suspension Inspection, Repair and Replacement.
Among the most hardworking components on any vehicle are suspension parts. When you think about the distance they travel and the repetitive abuse they’re subjected to—such as changes in vehicle weight and loading, along with a wide variation in the quality of the road surface (which can include anything from camber, to potholes, expansion joints, speed and frost bumps, and gravel and dirt surfaces) it’s no wonder they need to be regularly inspected for condition and operation. When you also factor in weather issues such as snow and slush, plus the brine and road salt counties and municipalities put down on winter roads, regular suspension checks are a must for service providers—ensuring their customers’ vehicles continue to function correctly and safely.
There are also other factors to consider, such as the durability of the parts themselves. As Victor Moreira, Technical Services Manager at Mevotech notes, over the last 25 years (particularly the last decade) increasingly aggressive Corporate Average Fuel Economy targets have pushed vehicle OEMs to look for weight savings—and a key area has been in chassis and suspension. Combined with the need to drive cost reductions, the result is lighter-duty parts that are designed for a specific warranty period. A good example is the widespread use of polymers, often in bearing designs and even the component itself. “Polymers have temperature performance limitations,” says Moreira, “so temperature extremes are more damaging to these compared with metal components.”
Additionally, he notes that consumer desire for better ride performance and ride comfort has seen more OEMs adopt multi-link suspension designs on their vehicles, which means more moving parts and, correspondingly, a greater risk of component failure.
To assess the health of a late-model vehicle’s suspension componentry, Moreira says it’s important for technicians to check tire wear patterns which can indicate everything from misalignment of the steering and suspension; to over or under-inflated tires bushing and even strut, damper or spring wear. “Look for cracked bushings or leakage from hydraulic bushings, as well as notable corrosion on structural components, especially centred around drainage areas,” explains Moreira. “Check the integrity of dust boots, including boots on tie rods and racks, to ensure component internals are being protected.” He also suggests performing a wheel shakedown and checking side-to-side wheel motion for signs of play in the steering and suspension, the more play, the greater the problem is likely to be.
Ride control considerations
Declining condition of ride control components, including struts and dampers, can have a very significant effect on vehicle performance though it isn’t always noticeable, particularly to the motorist. “Worn shocks and struts can greatly increase wear on tires and brakes,” explains Andy Castleman, Director of Product and Marketing, KYB Americas. “The front brakes do most of the work when stopping a vehicle. Worn shocks and struts can cause excessive nosedive during braking, causing premature wearing of brake components and tires while greatly increasing stopping distance.” Castleman recommends that service technicians perform a short road test to determine the current handling and control characteristics of the vehicle. Additionally, KYB offers a tool to enhance the process. “KYB’s 3 Minute Mile Road Testing App walks a technician through the road-testing process and provides a report and recommendations that can be passed on to the consumer.”
Regular inspections are also paramount. Robert Murgado, Director of Products for GSP North America, notes that ride control components need to be inspected every 80,000 km (50,000 miles) for signs of wear or damage “and at any service conduit beyond that point.”
He notes that GSP advises service centres and technicians to conduct a comprehensive inspection of all undercarriage elements including Ride Control, as well as Steering and Driveline. “This evaluation should also encompass brake wear, leak detection, and necessary servicing for interconnected components,” he says.
On the steering front, Dennis Mullen, Regional Sales Manager – East, for Plews Edelmann, says that technicians should check bushings for signs of wear and oil contamination as well as the condition of hoses on hydraulic systems. “Power steering hoses are subjected to a harsh environment. Operating temperatures can range from -40°F (40°C) to over +400°F, (+204°C)” he explains. Internally, hoses transfer fluid under pressures of up to 1,500 PSI and while transferring fluid, they absorb pressure surges and pulsations, causing them to expand and contract to help control noise in the power steering system. Additionally, says Mullen, “Power steering hoses must also resist external wear factors like ozone, grease, oil, road debris, wear from rubbing, and stress being applied from engine torque.”
Lack of regular power steering fluid changes is a common issue that can lead to greater problems with steering and suspension components, which is why it’s important to inspect the fluid every 3-6 months. “Power steering fluid accumulates any wear material from steering components, moisture, and other debris in the system. Replacing the fluid will remove these contaminants and keep the system properly lubricated.”
Choosing replacement parts
At Mevotech, Victor Moreira notes that when it comes to replacing suspension and steering components, one thing service centres need to consider is that OE parts are not always the best option. “They are built to a specific standard, and if you replace them with the same parts, they will likely fail under the same conditions. With more consumers feeling the financial pain of inflation and higher interest rates, there is a tendency toward keeping vehicles for longer, which means more servicing, repairs and parts replacement.”
Andy Castleman at KYB, notes that given the current economic challenges facing many consumers—there is a temptation to use low-cost replacement products, which should be avoided at all costs. “We have found, through independent third-party testing that many of these components provide little to no improvement over worn shock absorbers. While we have not seen increased failure rates, we have heard from consumers who are disappointed that the newly installed low-cost ride control units do little to return the vehicle to its originally designed control and handling specifications.”
That’s why, in order to capitalize on the opportunity to help customers keep their cars on the road longer and in prime operating condition, education is key. “The aftermarket offers different brands, with different levels of quality, durability and performance,” explains Moreira. “Customers need to be educated on the fact that certain brands out there are not simply reverse-engineered from the OE design. Some go far beyond that, addressing OE-compromised designs and weaknesses.”
He points to Mevotech’s own line of Supreme and TTX products that are designed to specifically address OE design and engineering weaknesses, providing customers with a strong, durable alternative that can help ensure their vehicle performs better for longer. “If customers know they have options, rather than just returning to the OE, then independent service centres can not only increase their revenue but also become a trusted advisor, offering parts that will help the customer in the long run. But first, they need to understand which brands are truly premium and which are just marketing hype.”