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The stop gaps

DON MILLS, Ont - Current brake technology is too labor intensive and not reliable enough to meet compliance and cost expectations, Frank Haselden of TST Overland Express told delegates attending the 3...

STOPPING POWER: You want brakes to be ready when you need them.
STOPPING POWER: You want brakes to be ready when you need them.

DON MILLS, Ont – Current brake technology is too labor intensive and not reliable enough to meet compliance and cost expectations, Frank Haselden of TST Overland Express told delegates attending the 37th annual Canadian Fleet Maintenance Seminar.

“You have to watch brakes all the time. It’s not something you can work on and forget about it for a year,” Haselden said. “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.”

Haselden was part of a panel of speakers addressing how to reduce brake defects. He outlined TST Overland’s extensive brake program, for its 490-tractor, 1,245-trailer fleet, saying it starts with a heavy reliance on data collection. Based on that data, TST Overland has moved to the exclusive use of long-stroke chambers and is now making the switch to short brake cams.

Those were moves that rang true with another panelist, Harmac Transportation’s fleet manager, Kevin Berry.

“Camshaft length is very important. The shorter your camshaft and assembly the less ‘twist’ or wind-up you will have…Always spec’ the shortest camshaft available,” Berry advised. “Long-stroke brake chambers are another real good spec’ to look at when purchasing equipment. The long-stroke chamber, when you can get it to fit on your equipment is an excellent way of allowing yourself that little bit extra in brake stroke. That extra 1/2 (inch) may be just enough to save your hide at the scales some day.”

The proper slack adjuster and the right shoes and drums are also key, according to Berry, who specifies exactly which drums and shoes a 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’s brake program also includes self-audits based on ISO standards, a solid preventive maintenance package, training for mechanics, drivers and dispatchers, the spec’ing of quality components and statistical analysis. Yet the brake system is the top repair by volume in TST Overland’s fleet and accounts for 24 per cent of its road calls.

Haselden said he believes his maintenance department is doing a good job staying on top of brake problems but it remains a tough area, “and we struggle with it.”

“There is a balancing act between cost, manpower and design of the brakes,” he said.

Another area fleet maintenance managers must constantly keep a lookout for is 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 – indicating there is a problem when the brake stroke is fine, or worse, indicate everything is fine when it really isn’t.

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, you will find an overstroke condition a great deal of the time. 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 affordable way to get brakes to burnish together.” n

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