Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Checking Frame Alignment
The main components of the frame are the side rails and the crossmembers. The rails carry the load. The crossmembers stabilize the rails.
The 5 types of frame misalignment are the following:
- Sag
- Buckle
- Diamond
- Sidesway
- Twist
A misaligned frame rail may move in the following directions from where the frame rail should be:
- Forward
- Up
- Down
- To the side
The easiest way to inspect the frame alignment is with gauges that are made for this purpose. Detailed instructions are normally supplied with the gauges at the time of purchase. There are no instructions for gauge use in the manual.
Whether you inspect the alignment with or without gauges, park the vehicle on a level section of floor.
Certain conditions call for preliminary inspections before inspecting the frame. Suspension or axle problems may make it appear that the vehicle frame is out of alignment. If an axle has shifted, diamond or sidesway may appear to exist when neither does exist. A weak spring may make the vehicle appear to have a twisted frame.
A visual inspection of the top and the bottom flanges of each rail may reveal the specific area where the sag or the buckle exist.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.