CONMET'S Roger Maye presented some outrageous examples of wheels on the loose, with videos periodically prompting some chuckles. But the issue really is no laughing matter.
“If you can't stop, steer, or keep the wheels on a vehicle, what could possibly be more serious?” he asked. “If you explode a transmission, the liability that happens after that is not critical. But if you can't keep the wheels on a vehicle, that's serious. Most of the things I've seen can be prevented.”
Maye, presenting “Wheels Flying Down the Highway; Pray Your Technician Didn't Install Them!”, was one of three in the Service Distributor Workshop. The others: “Brake Systems of the Future, Here Today, Are You Ready?”, by Meritor WABCO's Mark Melletat, and “Changes in Steer Axle and Suspension Technology,” by Hendrickson's John Knutson.
“This is what your technician deals with every day,” Maye said. “Since the caveman invented the wheel, this continues to evolve. How does a technician know what to do? I've seen things that make me believe some technicians know the answer better than others.
“But knowing the answer is not nearly as important as knowing where to find the answers. The important thing is knowing how to identify the system and then obtaining the proper service information. If you're working on these new systems, there's not a lot of magic if you've got the basics. But you're not going to intuitively know how to work on these new systems. So you have to learn how to make that service information your best friend.”
He said that at the Technology & Maintenance Council's (TMC) 2009 SuperTech competition, the average score was 948 out of 1500. On wheel ends, out of a possible 100, the average score was 47.24.
“As simple as wheel ends are, guys don't know all the answers,” Maye said. “What is the worst thing that can happen if you do not know the answer? Ask yourself this and then plan accordingly.
“I found out long ago that tools are a relatively significant part of it. Granted, you have to have tools and the skills to go with it. You have to have specialized tools, specialized training, and service information.”
How do technicians learn?
- By asking the old, experienced guy in the shop
“Technicians ask the senior guys, ‘What are the tricks?’ Handed-down experience … you can't put price on it. But the old, experienced guy may not be equipped. As rapidly as our industry is changing, it takes a new skill set to be successful in the modern shop. New technology requires new skills. Young guys know how to use computers. Old guys are still holding them at arm's length, in some cases. You're not going to survive without knowing computers.”
- By making mistakes
“Doctors get to bury their mistakes. Engineers get to live with theirs. The same thing goes for mechanics. You've got to live with mistakes, so let's help them out so they don't make them.”
- By reading service information
“Brian Lewis, the 2007 and 2008 TMC SuperTech grand champion, says it best: ‘If you want to be a good technician, the first thing you have to do is read the book.’ I've never seen a technician want to do a bad job. I've seen some that weren't equipped to do a good job. They just didn't know how.”
He said that at the TMC skills challenge, they run 18 technicians through a battery of tests.
“You learn a lot by watching technicians do the same thing,” he said. “Some come equipped to do it much more efficiently and accurately. The technician who won last year made an 88. He doesn't even do wheel ends, but he knows how to read instructions.
“We as manufacturers have the responsibility to make service literature as user-friendly as possible. Some of our service literature in our industry is not user-friendly. Engineers that write it take it from the beginning, but don't see it like the guy doing it for first time.”
He said the industry is full of new technology and fast- paced change. Spindle nut systems are part of that: castellated, multiple piece or double-jam nut system, Axilok, ProTorq, and unitized.
Lubrication comes as CD 50, 75/90 petroleum and synthetic, 85/140, semi-fluid grease, Grade 2 (hard grease), petroleum-based, and Grade 2 Synthetic. He said they have unique characteristics, and have to be identified and not mixed. An approved lubricants list is specific to each seal manufacturer, and there are proper fill volumes and hub caps.
Next Page: Brake Systems of the Future: Here Today, Are You Ready?
There are specialized tools, such as a torque wrench (“you can't do this business without one”) and a dial indicator. He said having a dial indicator is one thing, and knowing how to use it is another.
“These guys don't inherently know how to use precision measuring tools,” Maye said. “Find yourself an industrial gauging house, bring them into your shop, get your torque wrench and dial indicator from them, have them do a class for you to measure 1 in 5000th, and use tools. Read the instructions on a torque wrench. You're doing a precision job, using a precision measuring tool. You've got to have a calibration system. You've got to know that gauge is right. We have probably 5000 gauges in our shop. We control hubs down to 1/10 of a 1000.”
He listed these key steps:
- Hire the right people
“If Brian Lewis worked in your shop, do you think you could make money? Do you think they would improve the overall level of performance in the shop? You probably can't hire them, so why not train your own?”
- Provide the necessary tools
Test equipment, special sockets, dial indicator, torque wrench, calibration.
- Provide training opportunities
State maintenance council, dealer fleet nights, TMC, component manufacturer, Internet-based.
- Provide training opportunities
“Buy lunch for the shop one day a month and bring in your suppliers for training on their product. Chances are, the supplier will provide the training and pay for lunch.”
- Join your state maintenance council
“Send your technicians to the meetings. Take advantage of training offered at the monthly meetings. Meet the component suppliers for the industry.”
- Join TMC
“Attend the annual meetings (February and September). Receive the technical publications. Participate in developing recommended practices for the industry. Develop relationships with OEM and aftermarket suppliers.”
Brake Systems of the Future: Here Today, Are You Ready?
Mark Melletat, Meritor WABCO's Director of trailer systems, said today's advanced brake control systems require a building-block approach. The FMVSS 121 air system plus ABS provides a solid foundation.
He said electronics were mandated back in 1997 as required to meet the 121 regulation, and that implementation helped proliferate the use of these electronics in the market.
There are two stability-control systems available on market today for power units: Roll Stability Control (RSC) and Electronic Stability Control (ESC).
“All systems share the fact that they monitor,” he said. “They are receiving input through different sensors, compute those inputs, monitor different thresholds and then react with different trigger points within the system. There's automatic intervention regardless of driver input. In many cases, drivers don't realize there's a potentially dangerous situation.”
RSC is tractor/straight truck-based and addresses the roll phenomenon. ESC is tractor/straight truck-based and addresses roll and directional instabilities (oversteer, understeer).
With RSC, functionality is integrated in the power unit and the accelerometer is mounted directly to the ECU printed circuit board. When roll thresholds are exceeded, the SAE J1939 datalink is used to de-throttle the engine and apply the engine brake/retarder. Solenoid valves actuate the drive and trailer axle brakes.
With ESC, the module contains a gyro, lateral accelerometer, and software. There is a steer angle sensor for driver directional demand and one-pressure sensor for driver braking demand. When the roll and/or directional stability thresholds are exceeded, the SAE J1939 datalink is used to de-throttle the engine and apply the engine brake/retarder. Solenoid valves are capable of actuating the steer, drive, and trailer axle brakes.
“They have become more complex, and that needs to be recognized as you look at servicing these vehicles in your operation,” Melletat said.
OnGuard collision safety systems are forward radar-based, and designed to provide benefit or improvements as they relate to driver inattentiveness or different issues that could occur on roads today.
Next Page: Changes in Steer Axle and Suspension Technology
“Of the accidents caused by a delay in recognition, 90% could be prevented if the driver is able to recognize the situation approximately one second earlier,” he said, “so it's a pretty powerful statistic. We want the brakes applied sooner and at more appropriate times.
“The system maintains 3.1-second following distance and provides sequential activation of engine: torque reduction, retarder control, and foundation braking,” he said. “Maximum brake deceleration is 0.25g. What does that mean? It's about a 30% brake application, so it's pretty aggressive.”
Collision Mitigation is an “always on” emergency activation. It calculates to determine an impending collision and intervene. There is 0.35g brake deceleration (1/2 full brake apply). It functions at speeds of over 15 mph and automatically disengages if the driver takes appropriate action.
System installation includes a radar sensor mounted to the front bumper of vehicle, and sensor alignment is required to ensure proper field of view. There are four wire harnesses for power, ground, and datalink connections. The dash display provides visual and audio information, alerts and driver controls, with communication via SAE J1939.
Next Generation OnGuard is a system to include a lower-cost distance sensor with optional video camera and ultrasonic sensors. There is integration of distance and video sensors for redundant information gathering of forward objects, more exact object dimensioning, and sensor fusion that expands performance and functionalities.
Changes in Steer Axle and Suspension Technology
John Knutson, Hendrickson's technical support manager, gave service and maintenance tips for STEERTEK axles:
Hendrickson does not authorize bending of STEERTEK axles.
STEERTEK'S axle camber is not adjustable. Do not change the axle camber angle or bend the axle beam. Bending may result in structural damage to the axle and the warranty will be voided.
Hendrickson has not approved of any tooling intended to bend STEERTEK axles. Hendrickson's SEU-0227 technical bulletin warns against the use of any tooling to modify STEERTEK axles to change camber or for any other purpose.
He said if a STEERTEK-equipped vehicle is involved in an accident, fully inspect the axle beam, kingpins, knuckle assemblies, and any other parts of the axle assembly for signs of damage. Replace the complete axle assembly if: any component appears damaged; or the accident resulted in signs of an excessive side load, such as a bent wheel, hub, or spindle.