BENDIX BW7532 User Manual
THE CONSEQUENCES OF USING LOW-QUALITY, LOW-COST
SPRING BRAKES: A LOOK AT THE CRITICAL ISSUES.
OEM Quality Spring Brakes Maintain OEM Parking Capability, Deliver Longer Service,
Reduced Downtime, and Reduced Operating Costs Compared to Low-Quality/Low-Cost Alternatives
In the last several years, the commercial vehicle marketplace has been flooded with low-quality, low-cost spring
brakes. With today’s emphasis on protecting the bottom line, cost conscious consumers may purchase these lesser
quality products without full awareness of their potential pitfalls in the areas of safety and performance. When
choosing replacement spring brakes, it’s important for fleet operators to know what to look for in terms of brake
design and components.
Responsible for both service and parking brake applications, spring brakes are a critical
component in a commercial vehicle’s air brake system. The service side is used to slow
or stop a vehicle, while the parking side holds a vehicle in place when parked.
The longevity and operability of the parking side of a spring brake rests on its ability to
maintain sufficient force, over time, to hold a vehicle in place. The most critical
component for providing this force is a large, powerful spring that, in normal operating
conditions, stays compressed while the vehicle is in motion, and is released once the
vehicle is parked. Designing this spring for durability is critical, as a broken power
spring remains the leading cause of spring brake malfunction. Any failure means
certain vehicle downtime and increased maintenance costs.
Fortunately, owners of new vehicles can rest assured that their vehicles will stay in
place, as OEMs must certify that their braking systems meet Federal Motor Vehicle
Safety Standard (FMVSS) 121 parking requirements. However, no such standards exist for aftermarket products,
leaving the parking ability of low-cost aftermarket replacement spring brakes to chance.
To ensure that our spring brakes meet safety standards and deliver durability, reliability and safe operation, for
years Bendix has subjected these products to extensive ongoing research and benchmark testing in order to
compare elements related to such items as functional performance, corrosion resistance, and structural durability.
leaving the parking ability of low-cost aftermarket replacement spring brakes to chance.
To ensure that our spring brakes meet safety standards and deliver durability, reliability and safe operation, for
years Bendix has subjected these products to extensive ongoing research and benchmark testing in order to
compare elements related to such items as functional performance, corrosion resistance, and structural durability.
Among the battery of tests regularly undertaken, Bendix also conducts real world performance comparisons, of our
spring brakes versus low-quality spring brakes in a “hill hold” situation. While vehicle manufacturers traditionally
perform the FMVSS 121 park test using a drawbar, an alternative test for parking performance can also be
measured on a hill with a 20 percent grade. Using a fully-loaded single axle park tractor, a driver moves the vehicle
to the top of the grade and applies the parking brake to test how it holds on the hill. Bendix performed this test
using its OEM-specified Bendix
®
EverSure
®
Spring Brake with No Touch Technology. The brakes held fast, and the
truck did not move. Bendix then performed the test using a popular low-cost replacement spring brake. The results
were concerning, as the truck almost immediately lost its hold and started to roll back down the hill. Video of this
test can be found in the brakes and wheel-end section of the Bendix video channel on YouTube.com. To view the
footage, visit www.youtube.com/user/bendixvideos.
This test demonstrates how low-cost chambers can fail to maintain sufficient force output to hold a vehicle in place.
To avoid the uncertainty and safety risks that may be associated with low-cost, low-quality alternatives, fleets
should look to durable, long-lasting OEM products that will help keep their vehicles on the road.
were concerning, as the truck almost immediately lost its hold and started to roll back down the hill. Video of this
test can be found in the brakes and wheel-end section of the Bendix video channel on YouTube.com. To view the
footage, visit www.youtube.com/user/bendixvideos.
This test demonstrates how low-cost chambers can fail to maintain sufficient force output to hold a vehicle in place.
To avoid the uncertainty and safety risks that may be associated with low-cost, low-quality alternatives, fleets
should look to durable, long-lasting OEM products that will help keep their vehicles on the road.
Designing the spring
for durability is critical,
as a broken power
spring remains the
leading cause of spring
brake malfunction.
Any spring brake issue
means certain vehicle
downtime and
increased maintenance
costs.