Air suspension problems make it difficult to keep a truck level, maintain the correct ride height, and absorb road shock for a comfortable and safe ride. Issues with air suspension components can affect the chassis, brakes, and drivetrain. They can also affect tire wear—causing uneven wear and overheating—and reduce fuel economy.
Diagnosing and repairing air suspension issues is essential to keeping a fleet running efficiently. Keep reading to understand common problems, solutions, and how to prevent similar issues in the future.
How Truck Air Suspension Systems Work
Air suspension systems use pressurized air bags to keep the truck level and maintain appropriate ride height regardless of the cargo weight. These systems better manage changes in load than traditional steel springs would.
In addition to the air bags, which are large rubber bellows, the components of these systems include:
- Leveling Valves: These mechanical valves rely on sensors to know when to inflate and deflate the air bags to keep the load level.
- Air Lines: This tubing carries compressed air between system components.
- Air Compressor: The compressor supplies the system with compressed air.
- Air Dryer: This component removes moisture from the air suspension system, which is vital to preventing freezing, corrosion, and other issues.
Common Air Suspension Problems and Solutions
Understanding common air suspension issues, their causes, and how to prevent them can help keep trucks on the road and operating properly. Some of these air suspension system failures include:
1. Air Bag (Air Spring) Leaks
Air bags can leak due to punctures, dry rot, or age. When they do, the truck cannot maintain a proper ride height and will develop symptoms such as leaning, one corner sagging, or a compressor running more often than usual to maintain inflation.
It is important to regularly inspect air bags and proactively replace them as recommended by the manufacturer. Bump stops and debris shields should also be inspected to ensure they can still protect the system from road debris.
2. Faulty Ride Height/Leveling Valves
When there is an issue with a leveling valve or sensor, the system cannot determine how much to inflate or deflate the air bag to maintain the ride height. This can occur because of contamination, internal wear, or sticking parts.
If a truck has a leveling valve issue, it can cause the truck to sit too high or too low, or lead to slow adjustments when loading or offloading cargo. Excessive compressor cycling can also be a sign of a valve or sensor problem.
Regularly cleaning and lubricating moving parts and calibrating sensors are key to preventing leveling valve failures.
3. Air Line or Fitting Damage
Air lines and fittings can suffer damage that makes it impossible to move compressed air through the system efficiently. The damage can come from rubbing, corrosion, cracking, or debris impacts.
This causes hissing, slow fill times, and noticeable changes in ride height, even while parked.
It is possible to prevent many of these failures by using protective sleeves at rub points and routing the lines to avoid possible damage from sharp edges, hot surfaces, and moving parts.
4. Air Compressor or Dryer Failure
When the air compressor or dryer is not working as it should, the system may fail to work or fill wth moisture. This could also lead to other concerns, such as corrosion or valve failure. Signs include an overheating compressor, water in the system, slow system pressure buildup, or failure to fill the air bags.
When it comes to how to know if an air suspension compressor is bad, regular maintenance and inspection are most important. Fleet owners should replace dryer cartridges on schedule, drain tanks regularly, test compressor output as part of routine maintenance, and watch for excessive runtime.
5. Sensor and Electronic Controller Issues
Modern suspension symptoms use electronic sensors and control modules. While this helps systems work more efficiently and provide better data, it also increases system complexity.
Electronically controlled air suspension system problems include wiring corrosion, loose connectors, and software problems. The symptoms of a sensor or control module problem typically begin with an air suspension warning light, although inconsistent adjustments may also occur.
Regular electrical inspections and check-ups could prevent many of these issues. In addition, it is imperative to keep all firmware/software updated according to OEM standards to keep the truck’s electrical systems functioning.
Warning Signs Drivers Should Never Ignore
Almost every air suspension failure will show a tell-tale warning sign that there is a serious issue with the system. When it comes to identifying a problem as soon as possible, some signs drivers should never ignore include:
- Uneven trailer height
- Excessive bouncing
- Slow suspension reaction
- Air pressure alarms, warning lights, or data from diagnostic systems
How to Prevent Air Suspension Failures
Keeping a fleet of heavy trucks on the road requires regular inspections, preventive maintenance, and predicting problems before they occur. Knowing how to check air suspension systems and take action when necessary is key. This includes:
- Regular Inspections: Regular inspections of system components can identify cracks, loose fittings, moisture, and other issues before they cause significant damage.
- Replacing Components Proactively: Many parts of the air suspension system are meant to be replaced regularly. This includes air bags, leveling valves, and dryer cartridges. Replacing them based on the manufacturer’s recommendation can prevent failures.
- Proper Lubrication of Necessary Parts: All valve linkages and other moving parts should be cleaned and lubricated regularly.
- Driver Pre-Trip Checks: Before each trip, drivers should check the truck’s ride height, compressor behavior, and warning lights. Noticing a problem before leaving can prevent more significant concerns or road failure.
- Considering the Environment: It is imperative to consider the environment where your trucks operate and how it affects air suspension systems. Salt, moisture, and winter temperatures can increase the risk of problems.
When to Repair vs. Replace Air Suspension Components
When it comes to how to fix air suspension systems, your options will depend on the diagnosis and the necessary repair. In many cases, options include repairing or replacing a component. Making this decision often comes down to:
Cost Differences
Repair is often cheaper and faster, especially if the problem is isolated to one small component, such as a single air line. However, it is better to replace major components near the end of their typical lifetime.
Downtime Considerations
A planned replacement may take longer than a quick repair, but it can ensure one small issue does not turn into repeated, unplanned repairs.
Safety Factors
Repair should only be used when it can restore the air suspension system to full operation. Unless a repair can return the system to 100 percent, a replacement is likely a better and safer option. Safety should always outweigh short-term time or money savings.
Contact Our Team for Help With Your Fleet Maintenance and Repairs
Proactively maintaining your fleet’s air suspension systems can prevent failures, saving your company significant money and time. At Point Spring, we know that one planned component replacement is cheaper than an unplanned breakdown and tow.
We are here to provide expert repair support, including OE-grade suspension parts. Contact us today to learn more about our truck repair and maintenance services.