There's value in properly measuring and documenting all structural repairs, beyond just doing a good job.
Many of our industry personnel lack the training and understanding of how collision forces travel through vehicles. This article will help you understand the dimensionality of vehicles and how that relates to the proper repair of today's vehicles. I want it first understood that I am not out to bash any segment of the collision repair industry.
Repairers and insurers are having a difficult time finding and training future appraisers, estimators and technicians. For example, the foremost requirement by some insurance companies for entry-level appraisers is a college degree. I wonder how these individuals can estimate and dictate repair procedures when their only experience with a vehicle is as a mode of transportation. One insurer gives new hires a three-day training seminar and then puts that trainee in the field with a "seasoned" adjuster (someone who has worked for the company for six months).And many repair shops are so desperate for techs that a walking/breathing individual with tools is hired on the spot with a bonus and without checking his or her work background, knowledge or ability.
My reason for prefacing some problems with the collision industry is simple. I recently witnessed experiences that highlighted the problems of not understanding how collision forces affect proper collision repairs of vehicles that have suffered structural misalignment.
The first step in understanding collision theory is to better understand vehicle terminology.
Understanding terminology
DATUM PLANE: The datum plane is an imaginary flat surface underneath a vehicle that is parallel to a vehicle's underbody. Manufacturers use this plane during vehicle construction. A vehicle's height is measured from this plane, although there is no set height between the datum plane and the vehicle. For Example, Car-O-Liner will establish a datum height for its benches. If you use their measuring system on a competitor's frame machine, the computer will measure the new datum height and make the necessary adjustments to match their data stored on the computer's hard drive.CENTER-LINE PLANE: The next measurement is the vehicle's width. If you were to divide a unitized vehicle in half, you would create a zero reference in the center of the vehicle. This reference point is known as a center-line plane, which is an imaginary plane that divides a car in half and establishes a zero-reference point in order to measure reference point widths.
SYMMETRICAL AND ASYMMETRICAL POINTS: Symmetrical points are the same reference points that are equidistant from the center-line plane, whereas asymmetrical points are different widths from the center-line plane. These two terms will be very important later in this article.
ZERO PLANE: The last measurement I want to define is length. To understand how to derive a length of a reference point, we will set up what is known as a zero plane. We divided unitized vehicles into three parts: front section, the passenger section and the rear section. The front section meets the passenger section in an area known as the torque box area (usually directly under the "A" pillar).
The rear torque box area is where the passenger compartment attaches to the rear section of the vehicle. We want to set up our zero point at the farthest area from the damage. If a vehicle were damaged in the rear we would want to use the front torque box area as our zero plane or zero point. If a vehicle has sustained damage to the front, we then would set our zero point in the rear torque box area.MASH, SWAY AND SAG: Now that we have an understanding of length, width and height, the next step is understanding the types of damage that occur in a collision. When a reference point is shorter (length) than specification, we refer to it as a mash condition. A sway condition is when a reference point has a change in its width. When a point has changed either up or down in height, we refer to this as a sag condition.
TWIST, DIAMOND AND CENTER-LINE BOW: There are three other misalignment conditions that we also need to understand. A twist condition is when a part is no longer parallel to the datum plane (for example, the bottom of a frame rail is parallel to datum plane). A diamond condition exists when one frame rail is farther back or forward compared with the other rail. This condition occurs mostly with full-frame vehicles. The last condition, center-line bow, is a condition in which the center section is out of tolerance to the vehicle's center plane. It is normally due to a hard impact to the side of the vehicle.Without a through knowledge of the above terms, it really makes it hard to communicate as well as estimate a damaged vehicle properly. And without a proper estimate, a less than accurate repair could result. It is too important to dismiss the knowledge of the terms.
One last item and associated terms that need attention deals with wheel alignment. Camber is the tilt of the wheel inward or outward from the true vertical. Camber is viewed from the front of the vehicle. Caster is the tilt of the wheel forward or rearward from true vertical. Caster is viewed from the side of the vehicle. Toe is a measurement of how much the front and/or rear wheels are turned in or out from a straight-ahead position. Toe is viewed from the front of the vehicle.
Steering axis inclination is the number of degrees that a line drawn through the upper and lower ball joints (or strut and lower ball joint) and viewed from the front is tilted to the left or the right. This, in combination with caster, is responsible for the directional stability and self-centering of the steering. When dealing with unitized vehicles, the strut is attached to the apron and any misalignment of structure will cause an alignment problem. Let's say for example that the upper strut tower pivot point has moved inward 4 mm (about the width of four dimes stacked together) due to a collision. What effect will this have on the vehicle's alignment? Well, the vehicle strut will have more negative camber (half of one degree or more) and the inside of the tire will wear prematurely. Now let's look at how this lack of knowledge created a number of problems.A case study: Honda Element
A couple months ago I was at Autobody Hawaii preparing an article on frame machines with my buddy, the late March Taylor. One day prior to my arrival in Kona, a field adjuster from an insurance company was complaining to March's estimator that there was too much frame time. He said that setup and measuring should not take more than 1.5 hours and the tech pulled on the rails for less than two hours. He said he "wanted to be fair" so he allowed for three hours.
Before moving on, let's look at this repair. The Honda Element sustained side-frontal impact and both rails had mash, sag and sway conditions. The rails were not nicked, but they needed to be repaired extensively after pulling. Note the upper body measurement apparatus in place. And notice all of the holding and measuring fixtures that were needed for this proper repair.
So the obvious question is: How can anyone with any brains think that the car can be placed on the frame bench, secured down and all the tools necessary for measuring be done in 1.5 hours? Anyone with any collision knowledge would know that this whole operation would take a minimum of four hours. Okay, let's move on.I took more photos after the frame rail had been pulled. You will note that the upper strut tower had shifted inward about 4 mm. Also, the upper bolt on the driver's side was also misaligned by 4 mm. If March had not measured this, there would have been a problem with the vehicle's alignment. He pulled on the side of the upper structure to correct upper sway misalignment.
The picture of the upper strut bolt on the driver's side of the vehicle shows that it is at its correct width. The passenger's side bolt also moved over and it also was at its correct width. More and more of today's vehicles have reinforcements between the "A" pillars to add strength to passenger compartments when a side impact or rollover occurs.
These reinforcements along with a vehicle's sub frame create an intertwining of all the front-end structure parts. Thus, when one part moves, the rest of the structure moves and this is why it is so critical to measure not just the underneath structure, but the upper structure as well.
The two front rails moved again after correcting the upper strut tower bolts. With the upper structure clamped down to prevent side sway movement, both lower rails were pulled simultaneously to the correct locations. After assembly of the front structure, the vehicle was placed on the alignment rack. A four-wheel alignment was performed. It should also be noted that the same carrier did not pay for a four-wheel alignment. Their policy states that if the suspension is not removed, then only a two-wheel alignment should be done. Again, this type of blanket statement is a pile of manure. Before I go on, check out the neck pictures.What I have a problem with are blanket procedures set in place with no regard to the individual repairs by insurance bean counters who have no idea how to repair vehicles. The rear suspension needs to be aligned first. The in-spec rear measurements are then used to align the front suspension. Note that on the front alignment, there is a camber difference of .5 degrees between the two sides, but on this vehicle that much difference is with specifications.
I asked March to loosen up the sub-frame bolts to see what would happen, but he said that was a waste of time. (I told him he was a lousy mechanic and he responded with a few of his Hawaiian phrases, which I know were insults, but I have no idea what he was saying.) He did loosen up the bolts and taped on the supreme and when he re-measured the camber, the difference was .2 degrees. Think about this ladies and gentlemen, the vehicle went straight to the alignment rack from the frame rack and the vehicle was dead on. Finished within factory specifications the first time. What more can I say?A case study: Nissan Sentra
Our next scenario covers symmetrical and asymmetrical points. For this we used a 2005 Nissan Sentra that had sustained damage to the right front area of the vehicle. The rail had 15 mm mash, 28 mm sway and 16 mm sag. Both rails had moderate damage, but were repairable. The right front apron panel was damaged beyond repair. After pulling the structure back to specifications, first the upper strut mounts were measured and a second pull was necessary to correct the sway condition.
Both the driver's side and passenger's side strut mounts were at factory specifications. Next the front rails were measured. Again, note all the clamps that were necessary.
The passenger side rail was 145 mm from the center-line. The driver's side rail was 165 mm from the center-line. So the question is, which rail is out of specification? The answer is neither. These rails are asymmetrical. Look at the diagram taken from a Mitchell Data Book.
If the technician repairing this vehicle did not have a measuring system and the frame book, would he have known the rails were asymmetrical? Would he have pulled the rails so they were equal? Did the insurance appraiser have any knowledge of what was needed to achieve a proper repair? These are interesting questions, aren't they?A case study: BMW X5
During the same week that I was in Kona, a BMW X5 was loaded onto one of the other Super Rotax at the facility. The vehicle suffered a passenger-side, full-frontal impact. The adjuster wrote a sheet with two hours of pulling to the upper passenger side rail (kinked — needing replacement). His estimate had no setup time and measuring of the vehicle. When I observed the vehicle, it was quite obvious there was structural damage.
When we inspected the front and rear passenger side doors we noticed that the front passenger side belt molding was higher than the rear door molding. Also the door gap was not even from top to bottom. Both these indicators should lead any repairer to suspect that some sort of structural movement too place.
The measuring system was set up and a number of front-end reference points were measured to determine the extent of movement and damage that occurred from the impact.
Next the driver's side fender attachment bolt was measured and no structural movement was observed. The passenger's side front lower was measured and you will notice in the photo below that the rail has moved (a sag, mash and sway condition existed).After the structure was pulled to correct all front-end misalignment, the damaged sheet metal was removed. The new upper rails were held in place by fixturing jigs and all were measured prior to welding.
After the vehicle was assembled, the vehicle was aligned and as with the Honda Element, all the specs were in the green. I might add that the rear alignment was in specification and did not need any adjustment, but the rear did need to be checked prior to the front being adjusted.
A case study: Nissan Altima
As I mentioned in the opening paragraph, I wanted to look at both sides of the repair process and the next example took place at a dealer body shop. I was at this body shop and I noticed a tech installing a passenger's side apron and core support on a late-model Nissan Altima. What I saw blew me away – the tech was installing the apron assembly and core support on the floor. Yes, on the floor. No frame machine and no measuring system.
Maybe the vehicle was at its proper dimensions, but one would never know without any documentation. I find fault with the shop manager for allowing this type of repair to proceed. This car should have been on a frame machine with a measuring system (shop has both) and not done on the floor.
Speaking of documentation, I was recently in Marina Auto Body and my friend Tom Williamson related a story that fits into this article. Tom is a model for most shop owners on how to run a collision repair center properly.
A customer had brought in her 12-year-old Honda Accord with peeling paint on the roof, hood and deck lid. The vehicle sustained front-end damage to the passenger's side of the vehicle. The front bumper (used), right fender, lower control arm, upper tie bar, right headlamp (used) were replaced and repairs were done to the right frame rail (after pull), lower tie bar and front apron panel. The repairs were completed in January of this year and Tom received a visit from a California Bureau of Automotive Repair (BAR) inspector in August. The customer made a complaint about the paint not matching, the door hitting the fender and the vehicle pulling to the right.
Tom's shop has a written set of procedures for all types of repairs and every car has to follow them. In this case, the vehicle owner signed a paint problem waiver. The estimator told her the paint would not match due to the poor condition of the paint on the car. Next, for any car that is pulled there is a before and after repair slip printed out by the Car-O-Tronic and it goes into a file. Also, any car that has suspension damage gets a four-wheel alignment and those before and after slips also go into the customer's file.
Needless to say, the BAR inspector was taken aback. I guess he was not prepared for all of the documentation. About the same time that the BAR inspector was in the office the shop received a call from the insurance company DRP inspector. Again the tone was, "What had the shop screwed up now?" The insurance rep told the shop the customer was out in front of the shop, so the car was brought into the shop and placed on a hoist. Yes the fender and door were hitting. What was quite obvious to the shop owner and BAR representative was that the car had sustained new damage to the lower control arm and fender (probably from a parking lot concrete barrier — there was evidence of concrete transfer on the part). When the customer was confronted with this evidence, she said another body shop (it has many BAR citations) told her she could call her insurance company, make a complaint against Marina Auto Body and her carrier would take care of the repairs. And of course the other body shop advised her to say she did not want to go back to Marina Auto Body and would perform the new repairs at the other shop. The final outcome was that the owner of the car was on her own.
There are a few key lessons from this story: First, look at the time lost by Tom and his staff justifying their work. It's like paying a lawyer against unfounded charges just to prove you are innocent. And we all know that frequently body shops are considered guilty until proven innocent. Second, this shows the value of properly measuring and documenting all your structural repairs. If Marina had failed to do things the right way it could have been costly for the shop — in reputation and with potential business in the future.
