How many of you use the terminology "pull and square body" on your estimates? What does this really mean? The term was first used when unitized vehicles were introduced and we were still hand-writing estimates. Let me ask you another question. How many field adjusters reduce your quoted costs for "pull and square" when they see your estimate? Quite a few, I'd bet. Probably because it is a nebulous term and not very descriptive of exactly what is to be done . It therefore lends itself to be adjusted -- and not in your favor.

 

To begin understanding measuring and the terms associated with it, let's look at how a unitized vehicle is constructed. Vehicle manufacturers begin with placing the floor section on some sort of fixture at four control points. These four control points are mounted at a height above the holding fixture. The distance from the fixture to control points is known as datum height. The flat surface of the fixture is known as a datum plane. You need to understand that datum plane and datum height are arbitrary.

Think of all the different frame machines on the market and the different types of pinch weld clamps. Now place a '98 Ford Mustang on each of these different frame machines and you get 20 or 30 different datum heights (in this scenario the datum height is measured from the bed on the frame machine to control points).

Don't despair, each of the measuring systems will show you how to establish a datum plane and height and the datum plane will be constant with your particular frame machine and measuring systems. We can now find a height measurement for every point on a vehicle.

The second part of any measurement on a unitized vehicle is the width. Think of a car as an Oreo® Cookie but without the filling. Yea, I know it's not fun thinking of an Oreo without the filling, but what I want you to do is to rotate the cookie on its side and so each half is facing you. Now place a piece of paper between the 2 halves. You can measure the distance from the outside of one half cookie to the piece of paper as well as the other half and that distance will be equal. As with the datum plane, vehicle manufacturers establish center plane and that splits the vehicle in half. From this center plane, we will give this dimension a zero rating on the measuring scale. We can now measure from zero all points to the right and left of the center plane.

Here are two more words to commit to memory: symmetrical and asymmetrical. Symmetrical means that any point on the left side of the plane will have the same length, width and height as the same point on the right side of the center plane. Asymmetrical means that the point on the left of the plane will be different than the same point on the right side of the plane. Most of the asymmetrical points are usually found in the width dimensions.

To understand which points are symmetrical and which are asymmetrical, a good frame measuring dimensional book is essential. The latest electronic measuring systems incorporate this information in a computer database and conveniently display it on the system's video screen, but for non-electronic systems, a subscription to a dimensional book service is essential. Just imagine the problems which would arise if you did not have a dimensional guide and you assumed that all of the measurements to either side of the center line were symmetrical. You could pull that car all day and never get it right.

The next important term in unitized vehicle repair is mash. It is defined as a shortening of the length of the vehicle. When analyzing a mash condition, pay particular attention to crush zones and kinks that might occur in the collision. These items should be noted on the estimate and most often replaced as per I-CAR recommendations.

Sway condition is the movement of the structure to the right or left of the center line/center plane. When looking at a sway condition, play particular attention to sealant, which has a tendency to open up. I find this very helpful when trying to determine how far back the damage has traveled through the inner structure.

Sag, a term which refers to my stomach as I get older, also refers to the movement of structure up or down.

Diamond refers to a condition of one rail being farther back than the other. This particular condition is very common on ladder or full frame vehicles such as trucks. The final type of damage is twist, which is usually associated with the height of the center section of the vehicle.

Now that you understand these tems, lets start using them in the description of the damage when writing our estimates. For example, you should write "pull and correct sag condition" or "pull and correct sway condition" (2 separate line entries) instead of "pull and square body." These terms are more descriptive of the type of damage and of the scope of work to be done to correct it. With the damage correctly described, we are ready to measure.