Performance Friction's Zero Drag caliper has no slide pins, a design that limits deflection. This caliper can be used in race car, truck or school bus applications.
Fundamental to the operation of every vehicle on the road today, a well-built braking system can allow the operator to slow and stop in time for a stop sign, or avoid a dangerous traffic collision. The braking system on a school bus carries the weight of a larger-than-average vehicle and must protect the lives of the students on board, even under the strain of high braking temperatures and uneven terrain.
SBF spoke with three braking system manufacturers — Haldex, Smartbrake and Performance Friction Corp. — about hydraulic disc, secondary engine and air braking systems for the school bus industry. Choosing the right braking system for your bus, they agreed, is about strength, durability and finding the right features to suit the specifications of your vehicle.
Systems must properly handle vehicle weight
“A braking system needs to be engineered to match the amount of weight being carried over the axles,” says Scott Corbett, director, technical service and warranty for Haldex, North America. “Sometimes too much braking is not a good thing, so it really needs to be a matched system for the vehicle and the application that it’s in.”
Haldex manufactures air braking system components which can be assembled to fit school bus, truck, tractor or military applications. This includes air valves, brake actuators, friction materials and foundation component hardware. Vehicle manufacturers can assemble these parts to meet the braking needs of school buses or other vehicles.
“Having the right components for the application is the first and foremost concern [when it comes to braking systems],” Corbett continues. “And, after that, if [the system has] the right components, it’s basically maintenance and inspection after that to keep everything working properly.”
Braking systems from Smartbrake are calibrated to suit the characteristics of individual engines before installation. This allows them to be used to maximum benefit without compromising the integrity of the vehicle’s engine.
“We can apply our braking system to many if not all school buses,” explains David Phillips, vice president of Smartbrake.
The Smartbrake system is a secondary engine brake, and weighs less than a compression brake and transmission retarder. The lighter weight of the braking system allows for the vehicle to carry increased loads.
When it comes to hydraulic disc braking systems, Performance Friction Corp. applies the same philosophy to race cars and school buses alike: “You want light weight, you want low drag and you have to be able to handle high temperatures,” explains David Mohr, vice president of OEM and technical sales.
The company uses “Zero Drag” technology in most of its school bus applicable systems, which reduces temperature due to drag and off-brake wear.
“The Zero Drag brake system design has been shown to improve brake disc and pad life dramatically, and can save hundreds of gallons of fuel per year in commercial applications,” Mohr says.
While a lightweight braking system might not be as important in school buses as in heavy-duty trucks that need to carry increased payloads, Performance Friction offers lightweight brake systems that have aluminum calipers and floating discs to take weight down that can be used on buses.
“We’re trying to give the best possible brakes to the medium truck or school bus user so that he can lower his cost of maintenance,” Mohr says.