Checking Frame Straightness/Alignment

[Blue85]

Is there a way to check frame straightness at home?

[jku72]

There is a quick way I use, and that is to drive on to a flat surface, smooth concrete is best. With a very accurate tape measure measure identical points on each side down to the ground. You must have same size and same inflated tires. If the numbers all match side to side, there is a low likely hood of a bent frame. If your numbers don't match, your frame still might not be bent, but there is still the chance. Putting the truck then on jack stands and remeasureing can help determine if spring sag is an issue.
Usually, in my expirience anyway, bent frames are often only bent at the front and rear horns, from a collision. Cabs frequently sag, and the rubber bushings under the radiator support fall out giving the appearance of a lean, or bent frame. Dont put the jackstands at the frame horns, put them under the cab or under the engine cross member.

The official way is to get the factory frame measurement specification and do the full line of checks, but I'm way too busy to do that.

[Billla]

If the frame is bare you can get the "crash sheets" which have all the dimensions. Then all you need is a pretty darn dead level floor...which is usually the challenge.

[4x4Poet]

Its in the Service Manual. Look in Frame chapter for a fig. "Frame Horizontal Checking -Typical".

[TravisH]

If its a bare frame:
- do a corner to corner measure to determine if the frames square.
- lay a 4' level on the sections that should be straight to see any waves.
- run a stringline down the center of your crossmembers and take measurements to your frame rails to see if theres been any tweaking on the curved areas

If it passes the first step your frame is good, do the second two to pinpoint any damage if its out by more than 1/8".