Frame Repair Question

[scottmcwms]

I just got the body off the frame this past weekend and I was doing some damage assessment last night. The only rough spots on the frame are behind the rear spring shackles. I hammered on the entire frame with a chipping hammer and couldn't find any thinning except on the rear. The rear body mounts are completely detatched from the frame. Basically that whole area has been patched and repatched by the PO. Take a look at the driver side upper shock mount. This Bronco is filled with "creative" fixes like that. I'm surprised this thing didn't fall apart on him while going down the highway.

Back to the original point. I am planning on either patching the holes or replaceing the square tube from the rear shackle back. I read the Tech Article and it was very helpful, but it didn't mention anything about tube material. What tube material should I be looking for and what size? Is this just a mild steel or can someone give me an ASTM number to look for? Wall thickness???

If someone has a great condition frame in the Houston area I might be willing to take it off your hands for you. Might save me the repairs.

Thanks for your help. (I hope these pictures come out OK. This is my first attempt.)

 

[oh2bnok]

I had the same rust issue with mine. All I did was clean it up real good and welded a patch piece of 1/4 in steel over the larger hole, rust proof paint etc.

 

[malcolmzilla]

I don't think you need to cut off the back section, unless its all rotten.

I had the same issue on my 77, most Broncos will. It's a relatively simple fix if you have a welder and grinder. Cut back to good metal and weld in a 3/16" patch, then measure carefully and use a holesaw to cut the new bodybushing hole.

I see the frame behind the shock mounts has also been patched with angle, same problem on mine, might want to cut and investigate there too!

 

[wildbill]

;D ;D ;D I would think it would be best to remove it to the cross member and fab a couple new ones as that steel looks bad. H ave a fab shop make you 4 channel's the right size and weld them in and redrill all the holes and you will be good as new use 3/16 mild steel ( A36) Good luck. Bill %)

 

[scottmcwms]

use 3/16 mild steel ( A36) Good luck.

A36. That's what I needed to know.

 

[jeffdukovac]

You might want to have the frame sandblasted, to see if any other joys popup.

Jeff

 

[scottmcwms]

I don't have any way to get it to a sandblaster. I am going to flapperwheel the whole thing and then dye-penetrant check for cracks. Most cracks are going to be hard to see even with sandblasting. Dye-penetrant checking will reveal microscopic cracks. It's a lot of work, but well worth the time.

 

[jeffdukovac]

Your right - dye is the best way.

Remember to stop drill any cracks you may find.

Jeff

 

[SaddleUp]

Here are a couple of pics of one we repaired recently. If I recall right the material is 3/16" thick and was as close to a match to the frame size as we could get. Where it is spliced into the original frame it was fish mouthed and then the frame was heated and bent in to match it where necessary (I think the original frame was slightly wider) before it was welded. The original frame at the back was rusted out from the point in the back where it started to slope down (approx. half way between the spring hangers). The rest of it was solid. When he did it he made the section level since he planned to do a body lift anyway and then figured the difference. (I think it was 1 1/2" higher at the back than stock so those mounts have 1 1/2" blocks instead of 3" ones) A plus to this is he doesn't have a 3" gap between the bumper and the body now.