World American WA01-9978C Air Spring | Replaces Mack 8446-S28929 Filtration Verify your driveshaft yoke style

Verify your driveshaft yoke style (bearing plate vs half-round) and series before ordering — 1710 bearing-plate and half-round U-joints are not interchangeable

and ships with the cartridge plus the required seal package

excavators with Volvo D-series power)

and load rating against your existing air spring before ordering — multiple Firestone rolling-lobe springs share similar dimensions but differ in plate stud configuration

so this is the same filter installed at the factory

World American WA01-9978C Air Spring | Replaces Mack 8446-S28929 Filtration Verify your driveshaft yoke styleThe World American WA01 9978C is a heavy duty rolling lobe air spring engineered for trailer suspensions. Designed as a direct replacement for Mack 8446 S28929, this OEM equivalent spring delivers consistent height control, superior durability, and reliable damping for long haul and vocational trailers. Built to withstand harsh road conditions and heavy loads on highways and back roads. Specifications Category Air Springs Air Bags Part Type Trailer