Nothing can tarnish a fleet’s safety record faster than brake defects. Brake stroke and adjustment defects are the predominant problems uncovered during roadside inspections. Of the 19,775 truck brakes checked during Operation Air Brake in Canada last October, 4.6 per cent were found to be beyond the legal stroke limit. The results were twice as bad in the U.S. where of the 12,581 brakes checked, 8.3 per cent were found to be beyond the legal stroke limit. During this year’s Canadian Fleet Maintenance Seminar, three experts outlined what you can do to keep your trucks from adding to those statistics.

1. SPEC THE RIGHT COMPONENTS: There’s no better place to start. For Frank Haselden, this year’s Volvo Fleet Maintenance Manager of the Year, that means long-stroke brake chambers. That’s all he will use on his 490-tractor TST Overland Express fleet, which was awarded the National Fleet Safety Award last year.

“They give us more of a compliance cushion. They just make the tolerances not so tight so that if we do something that’s not perfect, we still have a safe, compliant brake system,” he explains.

Haselden is also in the midst of switching his fleet to short brake cams, a move echoed by Kevin Berry, fleet manager for Harmac Transportation Inc.

“Camshaft length is very important. The shorter your camshaft and assembly, the less twist or wind-up you will have,” he says. “Always spec the shortest camshaft available.”

The proper slack adjuster and the right shoes and drums are also key, according to Berry who specifies exactly which drums and which shoes the truck manufacturer should place on Harmac’s 200-truck, 400-tank trailer fleet.

“Sometimes, not all the time, the OEM will put on the bare minimum for brakes. Why should you not spec your choice? Your brakes will last longer,” he says.

Brake stroke indicators round out the list of components worth spec’ing to combat brake defects. They are a standard spec at both Harmac and TST Overland Express. Haselden said that his fleet decided to make the investment after realizing that despite extensive training many drivers still couldn’t tell if their brakes were out of adjustment.

“The tolerances are so small that, to be honest, I couldn’t tell you myself by just looking at a brake if it was out of adjustment,” Haselden said.

Haselden also issues a challenge to manufacturers to enhance brake safety and performance by improving on current brake technology, which he finds too labor intensive and not reliable enough to meet carriers’ compliance and cost expectations for today and tomorrow.

“You have to watch brakes all the time. It’s not something you can work on and forget about it for a year,” Haselden says. “The current braking system has been around for years and has served us well but I think with the level of compliance we are at now and we expect in the future, brakes have to go in a different direction.”

2. WATCH FOR SHODDY INSTALLATION: Spec’ing the components mentioned above is a costly project. Make sure it’s not undone by shoddy installation practices. For example, it’s not unheard of for factories to install the wrong slacks on a truck.

“Along with the wrong angles that turns into a large foundation balance problem,” Berry says. “When you have an imbalance in foundation components you will definitely have a stroke problem, maybe not right away, but down the road, definitely.”

Installing visual brake stroke indicators is a relatively simple process but if it’s not done properly it can lead to false readings – they will indicate to the driver that there is a problem when in fact the brake stroke is fine, or worse, indicate everything is fine when it’s really not.

Brake burnishing – the length of time it takes brake shoes and drums to properly wear together – poses another problem. Berry explains that if you perform a brake stroke inspection test on a new vehicle, or one already in your fleet that has had new components installed, a great deal of the time you will find an overstroke condition. The results will amplify with vehicles that have long camshafts, regular stroke chambers and low-end foundation components.

“One of the first things a driver thinks when he sees new brakes on a trailer is that it’s good to go. She’s got new brakes, hammer down, and let’s go. First scale, guess what? Yep, she’s good to go, right to truck jail,” Berry says.

He relates a story of a trailer that had just had a brake job only to spend 15 days in the Ontario Ministry of Transportation’s impoundment yard because 50 per cent of its brakes were out of adjustment.

“To ensure accurate stroking the wheel end in question must be jacked up and adjusted to the closest possible tolerance and still allow the wheel to turn freely,” he explains. If an overstroke condition still occurs, rolling brake applications are about the only manageable and affordable way to get brakes to burnish together.

“How many applications does it take to burnish the brakes? Well, that depends on many different factors. How fast you are going, what the gross weight of the vehicle is and how many axles it has,” Berry added.

3. EMPLOY A RIGOROUS INSPECTION PROGRAM: Everyone involved with the vehicle – from the driver to a subcontractor doing some of the maintenance on your trucks to the dispatch department – must understand the importance of a defect-free brake system in getting good results during government inspections.

Despite the advent of brake stroke indicators and automatic slack adjusters, Hans Jons, of the Ontario Ministry of Transportation, says the driver must remain an important part of that equation.

“We can’t ignore the driver’s responsibility to inspect the vehicle and not drive it unless it meets the minimum safety standard,” Jons says. “The fact this responsibility has not been fully embraced by some – I venture to say most – drivers, does not make it an optional requirement. The driver should be a direct link between the vehicle and the maintenance department.”

And don’t forget to educate the dispatch and operations people on how brakes work and the regulations they come under. Unless they’re on the same page they can quickly undo the best brake maintenance program.

“What we found was that while we were training everybody on brakes we would have a dispatcher or someone in operations who was in a hurry to deliver or pick up a load and they would be talking the driver into leaving,” Haselden recalls. “So it’s important to take the time to train dispatch and operations people.”

4. MAKE PM THE BACKBONE OF YOUR PLAN: Develop guidelines for your braking system components. When should the brake shoes be replaced, at what wear rate should the drums be replaced, what should be the allowable movement in the cam bushings before they need replacing? – these are the types of questions your maintenance shop should have ready and consistent answers to. Once you set your guidelines and communicate them to the shop technicians, audit the system on a regular basis to ensure compliance. The last step in this process is documentation.

“Documentation is one of the most important, if not the most important, steps that must be done after all the inspections are completed, ” Berry says. “Do your due diligence. Record the brake stroke measurements, record your foundation components findings during your inspection. Most importantly, be sure to document your procedure for doing so and what will be done when the brakes are not in compliance.”

5. ONE LAST CHECK: No matter how good your preventive maintenance practices are, things can and will go wrong in between PM intervals. Driver pre- and post-trip inspections offer that final safety check, provided the driver has been trained on what to look for.

“Drivers need to properly understand how to inspect their braking system. They need to know how to detect a defect and what to do about it,” Berry says. Harmac expects its drivers to complete pre-trip and post-trip as well as enroute inspections after so many hours of operation or miles traveled. It has a dedicated bay set up in its maintenance facility to assist drivers in com
pleting their post-trip inspections as well as correcting any defects found during the pre-trip inspection. The drive-through bay is operational seven days a week, 24 hours a day – an expensive endeavor to set and maintain, no doubt, but Berry says the investment is well worth the return in safe and compliant vehicles.