frame question

bronco-kid · Mar 20, 2013

Im on my second frame ,I have re welded all the factory welds.got the lift on diffs on when I put my body on the frame I have to put a 2 in body block at the rear bumper to get the body to line up. im thinking my frame has warped due to the heat from the welding. im wondering if anyone has the measurements from the body mount point to a flat surface(concrete floor??).I have measured the frame specs and they all are very close .I cannot find the body mount point measurements anywhere!!!!!

Bajabrewer · Mar 20, 2013

What lift do you have & where did you get it? Are the rear leafs stock height? Maybe you need 2" blocks between rear axle & leaf springs - that would equal the tall coils you have in the front.

bronco-kid · Mar 20, 2013

its a 3 in suspension lift from wild horse. when I put the frame on the body the body high centers. like the body support behind the seats (stock support) is to high.

JIMS74 · Mar 20, 2013

I measured from the top of the stock body mount locations to the garage floor, should be able to figure the difference. front 33 1/8" floorpan 30 3/4" behind seat 35 1/4" rear 35 3/4" hope this helps, good luck.

bronco-kid · Mar 20, 2013

exactly what I was askin for thanks a million jim!!!!!!!!!!!!!

bronco-kid · Mar 20, 2013

yep I got some serious frame issues!!!!! front 31 1/4 floor pan 28 1/8 behind the seats 31 1/2 rear 29 now I know what the problem is !!!!!! thank you

Steve83 · Mar 21, 2013

The frame can't warp overall from welding; just very small localized warps in the surface. But the frame doesn't have much strength on its own - it becomes rigid when bolted to the body. So if you bolt the body down with the frame twisted, you'll create a twist. Make sure the front suspension is neutralized (read all the threads about Bronco Lean) and that you're parked on a FLAT, level surface before tightening the body bolts or taking any measurements.

This diagram is accurate & scaled, so just use the pixels to get measurements that aren't displayed.

This video shows how flimsy a truck frame is, and although the eB frame is boxed, it's not significantly more-rigid:

707Bronk · Mar 21, 2013

If the measurements for both the left and right of the frame are nearly equal (left side of frame rail is parallel to the right side frame rail) then I would think that the problem isn't too terribly bad. However if you have some twisting going on then you may run into uncharted territory down the road.

AZ73 · Mar 21, 2013

There was a post here a couple of months ago where a guy posted pictures of his fuel lines on a body-off resto. People noticed strange plates on the frame just above the rear axle. When asked about them he said he had re-welded all the factory frame welds and had warped his frame. He had to cut it and weld plates in to put it back together. Hope that's not the case for you!

mnido · Mar 21, 2013

AZ73 said:
There was a post here a couple of months ago where a guy posted pictures of his fuel lines on a body-off resto. People noticed strange plates on the frame just above the rear axle. When asked about them he said he had re-welded all the factory frame welds and had warped his frame. He had to cut it and weld plates in to put it back together. Hope that's not the case for you!

That was me. Prior to welding the frame, body fit perfect. After welding, the center mounts fits perfect to the body, but and both ends there was 2'' of clearence. Given that, with a 1'' lift it would have required some tall blocks to make it right. I instead bolt up the center mounts, cut a slice in the frame from the bottom up, put a floor jack across the front and lifted frame into place with body. There was only a 3/8'' gap, so I welded the gap, then box plated the frame. Now it is great. I have some pictures if needed. The heat from welding the seams caused this to happen..

Bajabrewer · Mar 21, 2013

Glad you got the help you needed. I never would have thought welding would affect the frame that much. I learn new things on here all the time. Sounds like slicing, bending, welding, and plating is your answer.

bronco-kid · Mar 21, 2013

thanks for all the info guys!! got an appointment with the frame shop next sat.i keep you posted on what happens.

707Bronk · Mar 22, 2013

Bajabrewer said:
Glad you got the help you needed. I never would have thought welding would affect the frame that much. I learn new things on here all the time. Sounds like slicing, bending, welding, and plating is your answer.

Its good practice to assume whatever you are welding will distort. You should plan your welds based on how it will distort. The more heat you add, the more distortion you will have.

Fixing (bracing and clamping) is a huge consideration. Stitch welding is another stategy.

Or, you can plan your welds allowing for initial distortion. I have seen trailer frames get welded where the welds on top of the frame gets distort it like a V, but when you turn it over and weld the other half of the frame the distortion gets pulled back in perfect shape.

Do enough welding and you'll realize that making a simple jig beforehand can save you lots of time (money) in the end.

timmj68 · May 19, 2013

Steve83 said:
The frame can't warp overall from welding; just very small localized warps in the surface. But the frame doesn't have much strength on its own - it becomes rigid when bolted to the body. So if you bolt the body down with the frame twisted, you'll create a twist. Make sure the front suspension is neutralized (read all the threads about Bronco Lean) and that you're parked on a FLAT, level surface before tightening the body bolts or taking any measurements.

I noticed my Bronco was sagging in the rear driver's side after I finished installing a Wild Horses 1" body lift. If I'm understanding this correctly, I could have created a twist in the frame by tightening down the bolts before I had everything in place and level on the ground. Can I undo this problem by loosening the bolts and re-tightening them?

Thoughts?

Steve83 · May 19, 2013

If the bolts are twisting it, loosening them will let you UNtwist it.

But what exactly do you mean by "sagging"? Have you measured the frame in some objective way? Just looking at it in your driveway isn't conclusive - it could just be an optical illusion, or an uneven surface. Even a low tire.

timmj68 · May 20, 2013

Steve83, I measured the back of my Bronco from the ground to the top of the bedrail and the driver's side is 3/4" lower than the passenger side. The lean is more pronounced in the rear and almost unnoticeable from the front. I bought it last September and didn't notice the lean until after I finished my body lift. I thought that it was the old suspension components as they were original - as far as I could tell. After I put on the 2 1/2" suspension lift I still had the lean. After reading through this thread I thought that I may have put the twist in the frame during the body lift.

My thought is to loosen the body mounts and then slightly raise the drivers side rear to release any bind in the frame and then re-torque the bolts.

Thoughts?

timmj68 · May 20, 2013

- Follow up to Steve83

I also measured from the axles to the ground on both sides to make sure it wasn't a tire with low pressure. I don't believe the problem is with the body mounts since I also measured from the bedrails to the ground while I had the frame up on jack stands during the suspension lift and both sides were th same and the Bronco was level. I thought the lift had corrected the issue at that point...

Steve83 · May 25, 2013

So what happened? What were the axle measurements? Remember these trucks were built before robotic assembly lines & welding, so 3/4" isn't really that much variation, especially after ~40 years on the road & off.

conorm · May 29, 2013

I'm very interested to hear the results. I have a very similar problem and am trying to decide how to fix it.

Thanks!

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