Peterbilt Motors Company now offers the Bendix EnduraSure-Pro sealed spring brake as a factory-installed option across its medium- and heavy-duty truck lineup. The component is designed for use with air disc brake (ADB) systems. Bendix says the sealed design helps guard against moisture and contaminant intrusion, which is the most common cause of spring brake failure.
Highlights
- Peterbilt factory option: The Bendix EnduraSure-Pro sealed spring brake for ADBs is now available on all Peterbilt medium- and heavy-duty trucks.
- Corrosion resistance: The design eliminates park-side drain holes and uses a one-way check valve dust plug to block moisture and contaminants.
- Extended service life: In testing, the sealed design delivered up to five times the power spring life of a standard vented spring brake.
- Safety focus: A failed power spring in an ADB system is difficult to detect and may increase rollaway risk. The sealed design helps reduce that exposure.
How the Sealed Design Works
Bendix engineered the EnduraSure-Pro by removing the park-side drain holes found on standard spring brakes. In their place, the company integrated a one-way check valve into the dust plug. This allows air to escape while preventing water, dust, and aggregate from entering the unit.
That distinction matters because contaminants can accumulate inside standard spring brakes over time. As a result, drain holes may become blocked, which accelerates corrosion and degrades the power spring.
Durability and Testing
According to Bendix, the sealed spring brake has been validated in both laboratory and on-vehicle environments. In testing, the design delivered up to five times the power spring life compared to a standard vented unit.
The power spring is also designed to virtually eliminate coil clash. This condition occurs when compressed coils make contact and wear away protective coating, which can lead to corrosion and eventual breakage. Additionally, the spring brake uses a greater shut height to reduce stress and help maintain force output over time.
Safety Implications for ADB Systems
A broken power spring reduces the ability of a spring brake to hold a parked vehicle. On air disc brake systems, this type of failure is harder to detect than on drum brakes. Consequently, the risk of an undetected rollaway may increase.
“Air disc brakes deliver smooth, straight, and stable stops, with little or no brake fade – drivers love them on the road, and fleets love them in the shop, since friction changes can be handled much more quickly than drums,” said Frank Gilboy, Bendix director of Foundation Drum Brake and Actuators. “And when you factor in that ADBs also help support optimum performance of higher-level safety systems like full stability and collision mitigation, protecting them from the hazards of failed spring brakes becomes even more important.”
Total Cost of Ownership
Bendix positions the sealed spring brake as a cost-reduction measure over time. Fewer replacements mean lower roadside service costs and less downtime.
“The longer you own your vehicles, the greater the benefit you’ll see from avoiding frequent replacements of your spring brakes, including lower roadside service costs and reduced downtime,” Gilboy said. “For trailers, the total cost of ownership is even lower, since fleets keep their equipment longer, and it often sits for extended periods of time. Spec’ing a sealed spring brake is especially beneficial, because standard spring brakes are more susceptible to collecting moisture.”
Furthermore, Gilboy noted that sealed spring brakes have traditionally been popular with fleets in severe or off-road applications like bulk hauling. However, he added that carriers in all operating environments can benefit from the durability and safety advantages.
“We’re proud to have Peterbilt equip the Bendix EnduraSure-Pro sealed spring brake for air disc brakes on their trucks, helping to bring additional value, safety, and lower total cost of ownership for fleets and drivers in North America,” said Nicole Oreskovic, Bendix vice president of sales and marketing.
The EnduraSure spring brake lineup includes standard and sealed options for both drum and air disc brake applications.
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