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A healthy Infiniti QX80 stands tall, absorbs bumps with ease, and feels steady thanks to its air suspension and Hydraulic Body Motion Control (HBMC). When both systems work correctly, the SUV rides with confidence.
That changes the moment a “Check Suspension” light appears, the truck squats after parking, or every drive feels rougher than before. Owners often feel stuck between expensive repairs and ongoing uncertainty.
This guide explains why the QX80 suspension fails, how to diagnose the symptoms, and the repair paths available, along with a long-term solution: converting the system to traditional coils.
Demystifying the QX80’s Suspension System
The QX80 uses both an air-spring setup and HBMC. Together, they create a smooth and stable ride, but they introduce more parts that can break.
Air Spring System: The truck uses air struts instead of coils. These rely on a compressor, dryer, and height sensors to raise and lower the vehicle.
HBMC System: HBMC uses hydraulic cylinders and cross-linked lines to control body movement. It reduces roll in corners and squat during braking but can be costly when leaks appear.
This combination is why many owners face repeated repairs.
Common Problem #1: Air Spring & Compressor Failure
The rubber air bags inside the struts eventually crack or leak. When this happens, the compressor attempts to compensate and often burns out.
How to Spot It:
- One corner or an entire end of the vehicle sinks after parking.
- The compressor runs constantly or cycles on and off during short trips.
Repair Options:
- Replace the leaking air spring or install a new compressor. This helps temporarily but can lead to repeat failures.
- Convert the system using a Strutmasters QX80 Conversion Kit, which replaces the front air springs with coils and the rear with pre-assembled coil-over units. This removes all air-related issues.
Common Problem #2: HBMC System Leaks & Failures
HBMC is known for high repair bills. The hydraulic cylinders and the valve block can leak, causing the ride to stiffen and warning lights to appear.
How to Spot It:
- The suspension warning light comes on, and the ride becomes stiff.
- Pink or red hydraulic fluid appears near wheel wells or beneath the valve block.
Repair Options:
- Replace failed cylinders or the valve block, usually at dealership-level pricing.
- Use a Strutmasters kit with HBMC Delete components, which bypasses the hydraulic system and restores stable drivability without the expensive HBMC repairs.
Common Problem #3: Sensor and Electrical Issues
Height sensors, wiring, and control modules can malfunction and confuse the suspension computer.
How to Spot It:
- Height changes at random or the truck will not level correctly.
- Warning lights appear on and off without sagging.
Repair Options:
- Use an Infiniti-capable scan tool to identify and replace faulty sensors.
- Reduce failure points by converting to coils, which removes many of the sensitive electronic touchpoints.
Repair the Suspension or Convert to Coils?
Some owners choose to keep the factory setup, and others switch to coils to avoid future repairs. This section helps weigh both choices.
When Repair Makes Sense:
- The SUV is newer or still under warranty.
- Only one part, such as a single air spring, has failed.
When Conversion Makes Sense:
- The vehicle has high mileage or multiple components are failing.
- You want predictable, one-time costs instead of ongoing repairs.
- You prefer a simpler, more durable suspension design that maintains load-carrying ability. The Strutmasters kit removes both air and HBMC failure points and gives the QX80 consistent ride quality without the chronic repair cycle.
Conclusion
The Infiniti QX80 offers a refined ride, but the complex air and HBMC systems often create ongoing maintenance challenges. Understanding the symptoms and repair paths helps owners choose the option that fits their budget and long-term plans.
Many QX80 owners eventually shift to a Strutmasters conversion kit after repeated failures since it offers dependable performance and a clear end to suspension-related stress.
2014-2023 Infiniti QX80 4 Wheel Conversion Kit (QX14F)
$839.00
Convert Your Air Suspension To A Coil Spring Suspension. End Your Air Suspension Problems Forever... Strutmasters 2014-2023 Infiniti QX80 4 Wheel Conversion Kit (QX14F) is the perfect solution to your air suspension problems. Designed to be very affordable while still… read more
2014-2023 Infiniti QX80 with Hydraulic Body Motion Control 4 Wheel Conversion Kit (QX24F)
$939.00
Convert Your Air Suspension To A Coil Spring Suspension. End Your Air Suspension Problems Forever... Strutmasters 2014-2023 Infiniti QX80 with Hydraulic Body Motion Control 4 Wheel Conversion Kit (QX24F) is the perfect solution to your air and hydraulic suspension problems.… read more
FAQs
What causes the Infiniti QX80 to sag or sit lower on one side?
Sagging usually comes from a leaking air spring in the strut. When the air bag cracks or loses pressure, the vehicle sinks after parking. The compressor may run longer to compensate, which can lead to its failure later.
How do I know if my QX80 air compressor is failing?
A failing compressor often runs nonstop or cycles repeatedly during short drives. This happens when it struggles to keep up with leaks in the air springs.
What is HBMC on the Infiniti QX80?
HBMC (Hydraulic Body Motion Control) is a hydraulic system that connects the left and right sides of the suspension. It keeps the vehicle level during cornering and braking. When it leaks, ride quality becomes harsh and repairs can be expensive.
How can I tell if the HBMC system is leaking?
Look for pink or red hydraulic fluid around the wheel wells or near the center valve block under the vehicle. You may also notice a stiff ride or a suspension warning light.
Are HBMC repairs expensive?
Yes. Replacing hydraulic cylinders or the valve block often costs several thousand dollars. Many owners face repeated repairs as the vehicle ages.
Can electrical issues cause suspension problems on the QX80?
Yes. Height sensors, wiring harnesses, and control modules can send incorrect data to the suspension control unit. This may cause uneven ride height, random adjustments, or intermittent warning lights.
Should I repair the air suspension or convert it to coils?
Repairs make sense for newer or low-mileage vehicles, or if the issue is limited to one component. Older or high-mileage QX80s commonly develop multiple failures, making a coil conversion a more predictable long-term option.
What does a Strutmasters QX80 conversion kit replace?
The kit removes the air springs, compressor, and related components. It also includes hardware to bypass the HBMC system. After installation, the SUV uses traditional coils and shocks.
Will a coil conversion affect towing or load capacity?
No. The conversion keeps the vehicle’s towing and load capability. The only feature removed is automatic leveling.
Does converting the QX80 suspension stop future warning lights?
In most cases, yes. By removing air components and reducing reliance on sensitive height sensors, the conversion eliminates the common causes of suspension alerts.
