Misunderstanding of how much wriggle room is truly permitted by tolerances can lead to errors on a vehicle being measured, according to both I-CAR and Car-O-Liner experts.
Jason Bartanen, I-CAR Industry Technical Relations Director, called tolerance one of his least favourite subjects and ‘a crutch’. Car-O-Liner Training Academy Manager, Mike Hoeneise called it a tricky topic. “You have to open your mind a little bit,” he said. “Collision repairers confronted with a typical tolerance of 3 mm mistakenly think, ‘if I’m within 3 mils, I’m good’. However, if one measurement is +3 and another is -3, there’s actually 6 mm difference between the two points and you’ve exceeded the tolerance by 3 mm,” according to Hoeneise. “Instead, everything on the vehicle needs to be within 3 mm”.
Bartanen said that collision repairers needed to look at the entire picture, not a single measurement, and Hoeneise said he talks about the vehicle being centred, levelled and square. “If something isn’t centred and sits at +3, perhaps it needs to be pulled 6 mm to -3 so it is both centred and within tolerance,” he said.
Hoeneise added that sometimes tolerance considerations are component-specific.
He gave the example of two front frame rail flanges at different distances, with some sway. Attempting to key the vehicle to a centre measurement on an undamaged bumper bar might not produce the desired result and the frame rail itself might still be out of tolerance and lead to difficulty installing some other part like a headlight. Better to have the bumper bar off-centre +2 or +3 to keep the frame rails centred.
Another measurement issue might arise with advanced driver assistance systems. Some vehicles have specifications for the technology attached to it, but often, it’s nowhere to be found the OEM repair procedures. “What does a conscientious shop need to do during the pulling process to ensure the crucial ADAS technology sits where it’s supposed to be?”
Hoeneise suggests: “Check the components around it. If all those parts are where they’re supposed to be, it’s likely the ADAS system will be in the correct place. Asked by Bartanen how often he checked measurements, Hoeneise said, “I would check them after every pull.” He also said a shop will want to perform “three-section measuring” – front, centre and rear – on every vehicle.
A popular question to the Car-O-Liner Data Department involves measurements that seemingly don’t make sense, according to Hoeneise. “Occasionally, there is indeed an error on the data sheet or the manufacturer changed a vehicle’s dimensions. However, most of the time, Car-O-Liner traces it back to the shop having selected the incorrect data sheet or committing ‘some sort of user error’. Maybe the vehicle moved during the pull, or the measurement was done improperly,” he said. “The final consideration is of course to ensure the equipment is OEM approved.”
This article courtesy of John Huetter of Repairer Driven Education (RDE). Check out their website at; http://www.repairerdrivennews.com/ for this and many other informative and educational article on the collision repair industry.