A truck’s suspension system is the backbone of its cargo-hauling abilities and is critical for keeping things upright and moving smoothly. However, due to the heavy-duty nature of semi-trucks and the long distances they cover, the suspension system is prone to wear and tear.
Recognizing common suspension issues and addressing them promptly is vital for every semi-truck operator and fleet manager. We’re going to discuss the components of the suspension system, then we’ll look at some of the signs that your suspension may need attention, as well as some of the typical issues seen in the trucking industry.
Understanding a Semi-Truck’s Suspension System 
The first step to learning how to identify various suspension problems and how to fix them is to have a clear understanding of how a truck’s suspension works. Here’s a quick breakdown of the most common components:
- Springs: These are the core of the suspension system. They bear the weight of the truck and its load, and they absorb the energy from road impacts.
- Shocks: These dampen the bouncing of the springs, keeping the semi-truck stable, especially during turns or when navigating over rough terrains.
- Air Suspension: Many modern semi-trucks use air suspension for a smoother ride and better load-carrying capabilities. Air springs replace the traditional steel springs to provide adjustable support based on the load.
- Bushings: These small rubber or polyurethane components reduce the friction between the moving parts of the suspension system, providing a smoother ride.
- Control Arms & Linkages: These connect the suspension system to the chassis and help the wheels to move in sync with the vehicle’s body.
One of the best ways to ensure all components are in good shape, and are in safe, working order, is to have regular inspections performed. Routine checks by operators can help spot issues, and periodic inspections by professionals can help identify problems and address them before they worsen.
Common Signs of Suspension Problems
The earliest indicators of suspension issues often come from the truck itself, with various signs that can be picked up during regular operations. Here are some of the common signs that may point toward a potential suspension problem:
- New or Unusual Noises: Hearing squeaks, rattles, or clunks when driving over bumps or turning corners can be a sign of worn or broken suspension components. These noises shouldn’t be ignored as they often indicate loose or damaged parts.
- Excessive Bouncing or Rough Ride: If the ride feels rougher than usual or your truck bounces excessively even on slight road undulations, it’s likely that the shock absorbers or springs are wearing out.
- Misaligned Wheels or Uneven Tire Wear: A misaligned suspension system can cause the wheels to point in incorrect directions, leading to uneven tire wear. Additionally, if the steering wheel feels off-center or the truck pulls to one side, it’s advisable to have the alignment checked.
- Leaking Fluids: Shock absorbers are filled with hydraulic fluid which can leak when they begin to wear out. If you notice any oily or greasy substance around the shocks or struts, it’s time to get them inspected.
- Visible Damage: During routine inspections, visible signs of damage such as bent or broken components, rust, or excessive wear on bushings can be clear indicators of suspension issues.
Common Suspension Issues
The wear and tear from the constant hauling over varying terrains can lead to several common suspension issues in semi-trucks. Here are some of the various problems that are likely to pop up during your time on the road:
1. Broken or Worn-out Shock Absorbers
- Problem: The shock absorbers are crucial for maintaining ride comfort and stability. When they’re worn out or broken, they fail to dampen the oscillations of the springs effectively.
- Solution: Replacing the shock absorbers as soon as problems are detected will restore the ride comfort and stability of your truck while on the road.
2. Broken or Damaged Leaf Springs
Problem: Leaf springs bear the weight of the truck and its load. Over time, they may crack, break, or wear out, affecting the vehicle’s handling.
Solution: Inspecting the leaf springs regularly for any signs of damage and replacing them when necessary will ensure your truck can carry loads safely.
3. Worn Bushings
Problem: Bushings reduce friction between the various moving parts of the suspension system. Over time, they can wear out or become damaged, leading to increased friction and possibly other suspension issues.
Solution: Regular inspections and timely replacement of worn bushings will keep the suspension system functioning smoothly.
4. Air Suspension Issues
Problem: Air suspension systems offer a smoother ride and better load-carrying capabilities. However, they can experience issues such as air leaks or compressor failures.
Solution: Regularly checking for air leaks, ensuring the compressor is working correctly, and replacing any worn or damaged components will keep the air suspension system functioning optimally.
Regular Ongoing Maintenance & Periodic Inspections
A major part of semi-truck maintenance is making reasonable steps to prevent issues from developing in the first place, rather than only getting repairs when they’re needed. A well-maintained truck will have far fewer issues, and that goes for all systems and components, not just suspension.
First of all, make sure you’re receiving routine checks, or asking your drivers to do so, and reporting any unusual noises, vibrations, or handling issues immediately. Perform a walk-around inspection of the suspension system, looking for visible signs of wear, damage, or leaks.
Also, make sure that you’re getting periodic professional inspections. Trained technicians will have the knowledge and tools to identify and address issues that may not be apparent to the untrained eye. Ensure that the inspections cover all aspects of the suspension system, including the springs, shock absorbers, bushings, and linkages.
Preventative maintenance can save a company or owner-operator considerable amounts of money. Replacing worn or damaged parts before they fail can prevent costly repairs and downtime. Adhering to a preventative maintenance schedule based on the manufacturer’s recommendations or the truck’s mileage and usage can be an easy way to schedule maintenance ahead of time.
Finally, take the time to educate drivers and maintenance staff about the importance of a well-maintained suspension system and the common signs of suspension issues.
DIY vs. Professional Repairs
DIY suspension repair is often a way to save substantial amounts of money, and options for DIY repairs can be an incredibly cost-effective choice, especially for those who know their way around a tool set. It’s a great way to gain hands-on learning experience, although it can be time-consuming and may present challenges if the right tools or parts are not readily available.
On the other hand, professional suspension repairs ensure a level of expertise and efficiency that’s hard to match. Technicians at reputable service centers have the knowledge and tools to accurately diagnose and fix suspension problems quickly. Additionally, most professional services will warranty their parts and labor for a period following the work, so you know you’re covered if an unpleasant surprise pops up.
Trust Blain Brothers To Keep Your Rig Riding Smoothly
Handling a fleet or being an owner-operator comes with a range of responsibilities, among which ensuring the optimal performance and safety of your semi-truck is paramount. The suspension system, being a critical component of your vehicle, demands regular attention and professional care, particularly given the rigorous demands of long-haul transportation. Blaine Brothers understands the essence of a well-maintained suspension system, and we offer exemplary services tailored to meet the needs of semi-truck operators and fleet managers. Contact Blaine Brothers today to schedule a suspension inspection and repair appointment at one of our locations in Minnesota or Wisconsin.