may2022 - 26

SPOTLIGHT ON BODY & CAB
grades, for instance, spec'ing disc brakes is a good
idea. " CVS is the result of ZF's recent integration of
its Commercial Vehicle Technology division and
Commercial Vehicle Control Systems division,
formerly WABCO, which ZF acquired in May 2020.
Adoption drives ADB innovation
As disc brakes have gained in popularity, product
volume has increased over the past five years.
That has given manufacturers the confidence to
invest in product line expansions. The one-sizefits-all
approach from years ago has already started
to change.
" Now that disc brakes have been capturing a
» Generally speaking, wheels-on brake system inspections should occur every three to four months.
Photo: Bendix Commercial Vehicle Systems
Air brake breakdown
The integration
of sensory
technologies
and other design
improvements are
giving technicians
some assistance in
the bay, but nothing
can replace wellexecuted
brake
system PMs.
By Gregg Wartgow
E
» Meritor EX+ LS
Air Disc Brake
Photo: Meritor
26 Fleet Maintenance | May 2022
lectromagnetic braking systems likely represent
the future of heavy-duty trucking, but air brakes
continue to represent the present. Manufacturers
of both drum and air disc brakes (ADBs) have
continued making design enhancements, giving
fleets plenty of options to improve longevity while
simplifying maintenance.
When selecting a brake system, fleets should
consider the benefits of each style. Generally speaking,
drum brakes are known for their durability,
parts availability, and lower purchase price. While
a bit more expensive up front, ADBs are known for
their reduced stopping distance and fade.
" Fleets should evaluate duty cycles and lifecycle
costs, " said Joe Kay, director of engineering at
Meritor, a supplier of drivetrain, mobility, braking,
and electric powertrain solutions. " One key consideration
is routine maintenance. Overall, disc brake
maintenance is simpler and takes less time. "
With ADBs, Kay said Meritor has seen consistent
performance and feel regardless of duty
cycle. That said, the benefits of ADBs really shine
through on vehicles with brakes that run hotter,
such as city delivery, transit buses, and refuse
collection. " The rotor is exposed, so heat is easily
released into the atmosphere, which helps lengthen
service intervals and improve stopping performance, "
Kay explained.
" Disc brakes actually perform better when they
get hotter, " added Kevin Rose, director of fleet
sales for the Commercial Vehicle Solutions (CVS)
division of ZF Group. " If a truck is operating in
an environment with a lot of hills or mountain
larger piece of the overall equipment rate, we are
optimizing ours to fit particular applications, "
said Keith McComsey, director of air disc brake
and systems product group at Bendix Commercial
Vehicle Systems, a provider of safety technologies,
energy management solutions, and air brake
systems and components. " We are taking weight
out of the brake for some of the lighter-duty applications
such as linehaul. For applications with a
higher braking duty cycle, such as school bus
and refuse, we've optimized the pad friction, so
it wears at a much slower rate at a higher temperature
range where those applications tend to operate
at more frequently. "
Haldex, a supplier of brake systems and air
suspension systems for heavy-duty trucks, has
made improvements to its air disc brake caliper,
the ModulT. " This second-generation caliper is as
durable as its predecessor and has the same braking
performance yet is lighter at the same time, "
said Daniel Ślimakowski, Europe, Middle East, and
Africa fleet sales manager at Haldex. According to
Ślimakowski, disc brakes should balance durability
and weight for a fleet to reap maximum benefit.
ZF has made some improvements to its WABCO
MAXXUS 2.0 Air Disc Brake, including enhancements
to the internal adjustment mechanism.
" There is a significantly reduced opportunity to
have a hot brake or hot runner situation, " Rose said.
Fleets are also benefiting from improved seal
protection.
" We've done a tremendous amount of field testing
and have found that in some extreme climates
such as northern Canada, having redundant seals
that prevent water ingression and foreign particles
from getting into the adjuster mechanism, slide
pins, and throughout the braking system helps
eliminate the potential for downtime, " Rose said.
Meritor has taken steps to further guard against
debris and heat exposure. The EX+ LS Air Disc
Brake has several unique design features, including
an advanced seal protection that protects the
piston boot until the pads are significantly worn
and need to be replaced.
Manufacturers have also made advancements
that make disc brakes even easier to inspect and
maintain. Many disc brakes include built-in wear
indicators that are integrated into the caliper/
carrier. This provides a relatively easy way for
technicians to monitor pad and rotor wear in the
lead-up to performing a wheels-off inspection or
pad replacement.
Technology is helping improve the monitoring
process even more. For instance, pad wear

may2022

Table of Contents for the Digital Edition of may2022