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Freightliner Mb Line Air Suspension Helper Spring Kits

Freightliner Mb Line Air suspension helper spring kits

Starting at $471.95, AutoBuffy stocks 1 air suspension helper spring kits from Arnott. A helper spring kit installs inside or alongside a worn air bag to restore load-carrying capacity, level a sagging rear end, and reduce bottoming-out. When the air bag fails or weakens, the vehicle squats under load, handling suffers, and tires wear unevenly.

Signs your Freightliner Mb Line needs a new air suspension helper spring kit

  • Rear end visibly sags or sits lower than normal, especially when carrying passengers or cargo
  • Compressor runs constantly or cycles on and off trying to maintain ride height
  • Vehicle bottoms out over bumps that it previously handled without issue
  • Uneven tire wear on the rear axle caused by inconsistent suspension geometry
  • Harsh or bouncy ride when lightly loaded, then extreme squat when fully loaded
  • Warning light or ride-height error message appears on the dashboard instrument cluster

Which air suspension helper spring kit should you buy for your Freightliner Mb Line?

The main decision is whether you want a kit that supplements a still-functional air bag or one designed to replace the air bag entirely as a permanent coil-over conversion. You also need to match load rating and mounting style to your specific axle configuration, since kits vary by single-rear-wheel versus dual-rear-wheel setups and by intended payload range.

Coil-over air bag sleeve insert
Best for
Owners who want to keep the OE air suspension system intact
What you get
A rubber or polyurethane coil that slides inside the existing air bag, preventing full collapse without removing factory components
Bolt-in coil spring conversion kit
Best for
Owners replacing a failed air bag permanently to eliminate recurring repairs
What you get
Complete coil spring assembly that removes air bag dependency; lower long-term cost but loses self-leveling function
Progressive-rate add-a-leaf / helper coil combo
Best for
Heavy haulers and towers needing maximum load capacity
What you get
Stiffening coil or leaf paired with a helper spring for dual-stage resistance that firms up only under real load
Adjustable air-assist helper spring kit
Best for
Drivers who vary between light and heavy loads regularly
What you get
Manual or onboard-compressor-compatible bladder paired with a coil helper; tunable pressure lets you dial firmness to match the load

Air suspension helper spring kits brands we stock for your Freightliner Mb Line

Arnott
1 option · from $471.95

Replacing an air suspension helper spring kit on a Freightliner Mb Line

Moderate⏱ 1–3 hoursFloor jack and jack standsBasic socket and wrench setSpring compressor (if removing coil springs)Pry barPenetrating oil for corroded fasteners

The general process involves safely lifting and supporting the rear of the vehicle, relieving any air pressure from the suspension system, and removing the wheel or dropping the axle enough to access the air bag or spring pocket. The helper spring or insert is then seated according to the kit's instructions before the suspension is reassembled and the vehicle is lowered to check ride height. A post-installation alignment check is strongly recommended any time rear suspension components are disturbed.

Frequently asked questions

How much does it cost to replace air suspension helper spring kits on a Freightliner Mb Line?
Parts start at $471.95 on AutoBuffy. A basic sleeve-insert kit at the low end covers straightforward installs, while full coil-conversion or adjustable air-assist kits run higher. Add shop labor of one to two hours if you're not doing it yourself, and budget for an alignment check afterward.
Can I drive my Freightliner Mb Line with a failed air suspension helper spring?
You can drive short distances, but it is not recommended. A collapsed or missing helper spring lets the suspension bottom out, overloads the air compressor, and causes accelerated tire and shock wear. Payload capacity is effectively zero in this condition, making towing or hauling unsafe until the kit is replaced.
Will a helper spring kit make my Freightliner Mb Line ride rougher when unloaded?
A well-matched progressive-rate kit adds minimal stiffness at light loads and only firms up as weight increases. Poorly matched high-rate kits can make an empty vehicle feel harsh. Choosing a kit rated to your actual payload range rather than the maximum possible rating keeps unloaded ride quality acceptable.
Do I need to replace both sides at the same time on my Freightliner Mb Line?
Yes. Replacing only one side creates unequal spring rates left to right, which causes the vehicle to lean, pulls under braking, and unbalances load distribution. Even if only one helper spring has failed, install a matched pair so both rear corners behave identically under load.
Will a helper spring kit fix my Freightliner Mb Line's compressor running non-stop?
Only if the compressor is overworking because a collapsed air bag can no longer hold pressure. A helper spring insert props the bag open and reduces pressure demand, which can let the compressor cycle normally again. If the compressor runs constantly due to a leak in the air line or bag itself, the leak must also be repaired.
How long do air suspension helper spring kits last on a Freightliner Mb Line?
Quality rubber or polyurethane inserts typically last many years under normal use, often outlasting the original air bag they support. Coil-conversion kits have an even longer service life since they contain no air components. Longevity drops if the vehicle is consistently overloaded or exposed to road salt without protective coating.

Shop air suspension helper spring kits by year for the Freightliner Mb Line

1998199719961995

More parts for your Freightliner Mb Line

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Air suspension helper spring kits for other Freightliner models

Freightliner MT35Freightliner MT45Freightliner MB60Freightliner MB70Freightliner XB Line