Certain conditions call for some preliminary checks before actually checking the frame. Suspension or axle problems may be mistaken for frame misalignment. For example, a shifted axle may appear to be frame diamond or side sway. A weak spring may appear to be a twisted frame.

A visual inspection on the top and the bottom of the flanges of each rail may reveal an area on which sag or buckle exists. In the case of sag, wrinkles will appear on the top of the upper flange. Such wrinkles are definite evidence of sag. Wrinkles on the bottom or the lower flange are definite evidence of frame buckle.

The various types of frame misalignment may be divided into the following groups:

A misaligned frame may have moved forward from, upward or downward from, or to the side of its original position. Inspect the vehicle when such conditions are present. The most efficient way to check frame alignment is to use gauges. Detailed instructions are normally supplied with the gauges at the time of purchase. It is, however, possible to check the frame alignment without gauges.

Whether alignment is checked with or without gauges, the vehicle must be parked on a level, well-lit section of the floor.

1. Measure the distance from the frame rail to the floor at several different points along the rail.
2. Transfer these distances, in order, to a sheet of graph paper.
3. Connect the points, representing each distance, on the graph paper.
4. If the rail is straight, the points should all lie on a straight line.