The Stovebolt Site Forums The Shop Area Paint and Body Shop How do I determine if my frame is bent?

Guys,

I have a 53 3100 1/2-ton pickup that I'm wondering if the frame is bent. When I view the truck from the rear, it looks like it lists to the left. Measurements I've taken confirm this. My height from the ground to several points on the truck such as the running boards, bumper, fender wells show me I have a 1-inch to a 1 1/2-inch difference in height. I've also noticed this when putting the truck on jack stands. I will have to lift the truck an inch higher to clear the jack stand on the passenger side.

Where are possible ways to verify my frame might be bent? Or should I look elsewhere?

Measurements to the body from the ground don't necessarily mean the frame is bent. Springs, bushings, body mounts, etc could be worn instead. The body could be slouching on the frame if attachment points are rusted or pads and bushings are missing.

You'll have to take measurements from certain points on the frame to other points on the frame rather than just from the ground or from body panels. Hard to do with the body installed.

How does the truck drive? Does it veer to one side? Are the tires worn in strange ways (both front and rear tires)? Feathering in the treads, etc.

Have someone follow behind you while driving. Does it look like it goes down the street crab-walking?

Have you taken it to a shop for a 4 wheel alignment?

I would suspect the spring rather than the frame. If you jack up each side until the rear tire is just clearing the ground how do the height of the frame compare side to side?

Spring(s) sure would the lesser of two evils.

Try the test recommended by WICruiser.

It is a simple, quick check for any body shop with the proper equipment. Back in the dark ages, we used a series of fixtures that were hung from designated checking points on the frame and eyeballed the relationship between them. Now various types of laser measuring machines can check one out to within 1 millimeter (40 thousandths of an inch). Shade tree quesstimates don't make good nonsense. Pay a professional to do it right.
Jerry

All good suggestions. I'll look into these and see what I can find.

My guess is, since the “list is to the left”, it likely is worn out leaf springs. Most likely the left rear, but in replacing that one it would be best to do both left and right. In so doing the shackle hardware and bushings may and likely will, need replacement as well.

The only way I can think of to check for bent frame would be on a huge surface plate and using a 3 point set up to set it on. Would need accurate factory dimensions for the frame.

I suppose leveling it good, and a laser level could be done. Or a transit.

If you want to check for twist, you could use a magnetic angle gauge Example on the rear crossmember and front crossmember as it sits and compare the readings you get on each. To check for racking (one rail forward of the other) you need to use diagonal measurements from corner to corner. Hard to do unless the cab and bed are off.

But what the guys said about spring sag is likely what you're looking at.

Well, it's been a while since I posed the question. Today I got the answer. I finally pulled the rear springs out and took them down to the spring service shop and had them re-arched. After a battle trying to get the outer sleeve out of the rear shackle, the reworked springs went back in without too much trouble.
After getting everything back in and the tires put back on, once I set it back on the ground everything straightened back up. The back end not only sat square again, but it also raised the back end about 2 inches. So, it was definitely old tired and worn-out springs causing the problem! Now time to move on to the front end.

Thanks for following up with a final result of what you found and congrats on it being an easy fix (springs VS bent frame)!

You got any to go along with the info???

Would be interested to see before and after shots if you have them.

That's good

Dan, this is the best I have. Not the best for seeing the difference. In the newer photos, you can see the rear end sits higher and square. Plus, it has more of a forward rake to it.

Doug,

Thanks for the before and after pics!

The stance is very much back to how it should be.

That's great to know Dan!!