Let’s Just Do It

So, we’ve got a problem with our braking systems, do we? Well, the problem that was highlighted in ‘Bad Brakes?’ in highwaySTAR’s August issue has been with us for some time now, and I’m glad to see it once again receiving the attention it so richly deserves. The potential for problems resulting in failures in braking systems configured for spring-brake priority is still with us, despite some honest effort from a group I was associated with in British Columbia in the mid-1990s. I hope this go-round produces more lasting results.

I was working in the air and electrical department of a certain specialized trailer manufacturer when the FMVSS-121 [U.S. Federal Motor Vehicle Safety Standard, mirrored in Canada] issue arose in 1992. Soon after modifying our builds to suit the then-new standards, I realized the potential for catastrophe, and set about designing a low-air warning system to alert drivers to a service-line failure. The problem was, Transport Canada refused to consider the system because it constituted a “modification” of the existing brake system. I was told by Transport Canada that installing such a system would violate federal law.

All I wanted to do was to install a pressure-sensitive switch in the service reservoir of the trailer that would activate a standard HD13E flasher unit – wired into the trailer electrical system – when a low-air-pressure condition was detected. This would cause the turn-signal flashers to blink alternatively left and right to warn the driver.
In the article, you reported the Ontario Trucking Association had made several recommendations for fixing the problem. As I read it, OTA has proposed a complicated fix that would add considerable cost to the system and penalize technicians, while ignoring the real issue – the flawed standard.

Addressing the design flaw, I would immediately retrofit RE6 (or equivalent) relay emergency valves into every trailer out there, but there are other relatively simple fixes as well. As for the issue of being able move a disabled trailer off the road, there are several ways to re-plumb existing systems, including the installation of a hostler valve to release the spring brakes in an emergency. To my way of thinking, allowing a fix that permits the movement of a trailer with no brakes is an open invitation for someone to ask, “Can you get it back to the yard, or at least to the next truckstop?” That is completely unacceptable.

One other aspect of the OTA’s recommendation troubles me: the suggestion that drivers might close the trailer supply valve (pull the red button out) to cause the spring brakes to apply in the event of a service-system failure. Closing the trailer supply valve on a non-ABS-equipped tractor fitted with a bobtail relay (proportioning) valve will result in a jackknife almost every time if any brake application is used. When the supply line is closed, and the proportioning valve is limiting application of the tractor drive-wheel brakes, a driver would have to make an application of at least 40 psi to get air to the drive-wheel brakes, which will lock up the steer-axle wheels every time.
The correct procedure is to pull both the red and yellow knobs together, and use the brake pedal to apply the steering brakes. Once the unit stops, push in the red knob and fill the trailer maxi system, then push the yellow knob back in! This allows the driver to retain steering, saves air for further braking, and stops the bobtail relay valve from limiting the drive-axle brakes.

So, do we have a problem here? Yes. Can we live with it temporarily with some tinkering and vigilance? Yes. Do we need the draconian solutions proposed by OTA? No. Do we need to do a better job of training technicians and drivers? Yes.
While I am usually a strong believer in harmonization, and would like to see more co-operation between jurisdictions, this situation is a perfect example of how a lack of understanding of the functionality of the system, driven by the perceived need to harmonize standards, has resulted in a condition that continues to jeopardize lives on our highways.

Ian Vaughan is a certified heavy-duty mechanic who holds a B.C. Dept of Railways Air Brake Certificate. He has worked on truck and trailer brake systems for over 30 years and has over a million miles under his belt as a heavy-haul driver. He is a certified B.C. vehicle inspector and holds an unrestricted B.C. commercial driver’s licence. He is still active in the fleet safety field, and is presently the webmaster of the popular trucker website, Trucknet.ca.

--The opinions expressed in this column are those of the author. They do not necessarily reflect the views of highwaySTAR’s editors, staff, or advertisers. While we strive to serve the interests of the reader, we can’t guarantee the accuracy of the material presented herein. Submissions to “In Your Own Words” may be edited for length, punctuation, and libelous assertions and allegations.

ian@trucknet.ca

Currently Online @ highwaySTAR

Click. Click. Click. Old World Trucking Soot 'N Stuff Let?s Just Do It