+ applicable tax
Your air spring just blew — the truck is sitting crooked, the frame is riding on the internal bumper, and every bump feels like a jackhammer through the cab. On a commercial truck, a failed rear air spring isn't just an annoyance — it's a load-destroying, frame-damaging, DOT-violation-causing emergency. The longer you drive on a blown bag, the more damage you're doing to the opposite air spring (which is now carrying double the load), the frame crossmembers, and the cargo.
Replace both sides at the same time. When one air spring fails, the opposite side has endured the exact same mileage, UV exposure, and load cycles. It's not a question of if the other side will fail — it's when. Replacing both sides during the same service stop saves you a second tow, a second labor charge, and a second day of lost revenue. Two bags, one job, one bill.
This is a complete air spring assembly — not just a rubber bellows. Everything you need to bolt it in and air it up:
Some suppliers sell just the rubber bellows (the bag only) at a lower price. This forces the mechanic to reuse the old bottom piston — which is almost certainly corroded, pitted, and will leak immediately or within days. You then have to pull the truck off the road again, order the complete assembly anyway, and pay labor twice.
Always order the complete assembly. The labor to install a bellows-only bag is the same as a complete assembly — but the bellows-only job has a much higher failure rate because you're sealing new rubber against old, damaged metal.
This air spring directly replaces or cross-references the following part numbers:
All of the above part numbers refer to the same physical air spring in different branded packaging. If your parts catalog calls out any of these numbers, this assembly fits.
This air spring fits commercial trucks utilizing the following rear air ride suspension systems:
⚠️ Verify your suspension model before ordering. Not all Freightliner Cascadias use the Neway RL228/KL230 system — some use Airliner or other suspension packages. Check the suspension model tag on the frame rail near the rear axle, or contact us with your truck VIN for confirmation.
Why did my air spring fail?
The most common causes are: age and UV degradation (rubber hardens and cracks over time), overloading (exceeding the spring's rated capacity), road debris puncture, and chemical exposure (fuel, oil, or hydraulic fluid on the rubber). In most cases, it's simply mileage — rubber wears out.
Can I replace just one side?
You can, but you shouldn't. The old air spring on the opposite side has the same wear and will likely fail soon. When one side is new and the other is old, the ride height and spring rates will be slightly different, causing uneven tire wear and inconsistent handling. Replace in pairs — the extra cost is a fraction of a second service call.
Is this the same quality as a Firestone W01-358-8184?
Freightliner and SAF Holland do not manufacture air springs — they source them from Firestone Industrial Products and Continental (ContiTech). The OEM part number is simply a Firestone or Continental bag with a truck manufacturer's label. This assembly meets the same specifications for dimensions, load capacity, and burst pressure.
What's the internal bumper for?
The internal rubber bumper is a fail-safe. If the air spring loses all air pressure (blown bag, severed air line, compressor failure), the bumper prevents the truck's frame from slamming down onto the rear axle. Without it, a sudden pressure loss would cause frame-to-axle contact that can bend suspension components, crack frame crossmembers, and destroy cargo. Never run an air spring that doesn't include an internal bumper.
Restore your ride height and protect your cargo. Premium heavy-duty rolling lobe rear air spring assembly for Neway RL228 and KL230 air ride suspensions. Complete bolt-in assembly includes top bead plate, high-strength rubber bellows, bottom piston, and internal fail-safe bumper. Direct drop-in replacement for Freightliner/SAF Holland HLD 90557290 and 90557308. Cross-references Firestone W01-358-8184 and Continental 600932. Save $75+ vs competitors, $200+ vs dealer.
