At a minimum, Bendix recommends draining the air reservoir and checking for moisture in the system every 25,000 miles, three months, or 900 hours under standard air usage conditions; every 12,000 miles, two months, or 450 hours for medium air usage; and for heavy air usage vehicles, every 6,000 miles, one month, or 300 hours.
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Replacement intervals also depend on the type of cartridge: A standard OEM-grade cartridge, an oil-coalescing cartridge, and an aftermarket replacement have different performance expectations.
Bendix’s new service intervals were created with its own specific dryers – its standard cartridge; the PuraGuard® oil-coalescing cartridge; and the Bendix® GC™ Green Cartridge – in mind.
Check out this tool from Bendix: Recommended Service Intervals for Bendix® Air Dryers.
Recommended Service Intervals
For easy reference, Bendix categorizes vehicle air usage into three general levels: standard, medium, and high.
Standard use: Five axles or fewer; line-haul; city; delivery should be replaced every 24 months or 200,000 miles.
Medium use: Pulling double trailers; light transit; light off-highway; eight axles or fewer – should be replaced every 18 months or 150,000 miles.
High-air-use: Such as multiple trailers, city transit, heavy-duty off-road, and nine or more axles should be replaced every 12 months.
Vigilance is particularly key with oil-coalescing cartridges because of the specific job each medium has within the component: The oil filter doesn’t remove moisture, and the desiccant isn’t designed to remove oil – but both are crucial.
Especially on newer trucks, oil-coalescing filters are protecting components that can carry a significant repair cost. If your truck was originally equipped with an oil-coalescing cartridge, it’s important to replace it with one. And you can always upgrade from a standard cartridge to an oil-coalescing version, even if it’s not OEM spec: It’s just an added level of protection.
For OEM-grade standard Bendix cartridges without oil-coalescing technology, the recommended standard/medium/high usage replacement intervals are 24, 18, and 12 months, respectively.
For the Bendix® GC™ Green Cartridge, which is intended for older trucks and uses a proprietary mix of new and Bendix-remanufactured desiccant, recommended replacement intervals are 12 months for standard and medium usage, and six months for high.