Source: This is the latest in the ongoing series of Tech Tips presented by Bendix Commercial Vehicle Systems.
AVON, Ohio – All trucks get dirty. But some jobs are dirtier than others and require extra care to prevent contamination and corrosion that can affect brake performance and safety. This installment of the Bendix Tech Tips series provides fleets and drivers with advice on protecting wheel-ends in off-highway and severe-duty applications where dust and dirt can accumulate quickly and damage components.
“Air chambers have been required on air-braked commercial vehicles in the United States for decades, so the spring brake has been a crucial part of wheel-end safety for a long time now,” said Mark Holley, Bendix director of marketing and customer solutions, Wheel-End. “By design, they help ensure you still have brakes even if you have a wheel-end that’s inoperable. Keeping the spring within the brake chamber intact and corrosion-free is key to maintaining this capability – a broken power spring is the number-one reason for failure, most often caused by contaminants that get into the chamber and weaken the spring.”
It’s a critical enough component that the American Trucking Associations’ Technology & Maintenance Council (TMC) Recommended Practice 604D stresses, “Always replace service or spring brake chambers if there is evidence of significant corrosion damage. Any holes that penetrate through the spring housing or service housing are dangerous and are cause for the chamber to be replaced immediately.”
While standard chambers are manufactured with drain holes to prevent buildup of corrosive moisture inside, there’s an added risk of these holes becoming clogged by dirt or debris on trucks that operate in environments like construction sites, or on vehicles like cement trucks with axles that are regularly exposed to high levels of grit and dust. The same can be said of chambers on the axles of some types of bottom-dump trailers. Protecting the spring brake chamber life in these applications requires a combination of regular cleaning and inspection.
“When the truck is in for regular maintenance or lubrication every 45 to 60 days, use a plastic pin to clear dust from the air holes,” Holley explained. “If they’re blocked, then that spring is going to fail at some point. Then, remove the dust plug so you can use an air hose to clean the chamber. Don’t forget to replace the dust plug afterward. You should also use a pressure washer to clean the exterior, but again – you’ve got to make sure the drain holes are clear first so you don’t trap water in the chamber housing.”
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