Rusty Frame Issues

[73737373]

Some advice needed regarding the best way to proceed. Where the rear coil spring cups bolt to the underside of the frame, has rusted thru the frame and coil spring cup mount support. In that same area, the frame has vertical cracks on the outer sides; about 1/2 inch on driver side, about 1 1/2 inches on the pass side. There are 2 supports on each side that I've removed, also, in addition to the spring cup supports. These supports run along the inside of the frame and are riveted on.

Thoughts? thanks.

[mechanicalman]

Originally Posted by 73737373

Some advice needed regarding the best way to proceed. Where the rear coil spring cups bolt to the underside of the frame, has rusted thru the frame and coil spring cup mount support. In that same area, the frame has vertical cracks on the outer sides; about 1/2 inch on driver side, about 1 1/2 inches on the pass side. There are 2 supports on each side that I've removed, also, in addition to the spring cup supports. These supports run along the inside of the frame and are riveted on.

Thoughts? thanks.

In lieu of seeing a picture, I'd recommend buying an old longbed frame and cutting/splicing it in the same manner as a frame shortening only just leaving the desired wheelbase.

You can cut in front of the suspension cross-member and you can do a "Z" cut/weld with fishplate, box, frame stiffeners or any combo (you will have to remove the cab).

http://www.classicperform.com/Store/...ck/6372RFS.htm

Or make the cut behind the rear cross-member (cab can stay on), but if you cut behind it there is not room to do a Z cut. You can fishplate or box it or both, here is an example (I'd box over a fish plate like that). If the vehicle being repaired is a long bed, there is more area behind the suspension cross-member to work with and you could use the frame stiffeners but you would have to cut them down to about 12". You could fish-plate that then turn the stiffeners outward to make a box then put bolts through the top and bottom rails.

Remember, if you cut in front of the suspension cross-member there will be more force imparted on the repaired area, although it's really not an issue if it's done right.

There is less of an area to work with behind the cross-member but there is less force imparted on that repaired area as the suspension cross-member bears the brunt of the torque generated from the rear wheels leaving the rear of the frame to carry the bed and weight of cargo. Again, if done right, no problems.

If you tow, that extra force of the towed vehicle is imparted on both areas but still the brunt of the force is on the rear suspension crossmember.

http://www.classicperform.com/Store/...ck/6372RFS.htm

[deadbodyman]

Have you closely inspected the rest of the frame????? no sence repairing it if its rusted thru somewhere else....
Im in the process of replacing my frame its not very hard at all. My frame was bent and twisted so
I bought a complete and straight frame for a 69 short bed for 300.00 here in Ga. theres still plenty of them around. then sand blasted it and now its in the shop getting c notched and a few other mods before epoxy and paint.
what was surprising is how the prices varied (from 300.00 to 1500.00) and the 300.00 one was better . I looked at three and found a good one and saved a ton of money I never even got a chance to look in the Upullit yards where theres at least 10 69-72's locally.it pays to look around. You cant even repair a rotted frame for 300 even if you know how to weld and cut one and do it all yourself...
something to concider is swapping it out, its faster and cheaper and requires less experience. although not as much fun.you'll probably need to order all new body and rad support mounts before you get started.

[73737373]

Thanks for everyone's input. This is a long bed truck. Trying to find out what's "right" so when I do bring it to a shop, I'll have an idea. Yeah, should've posted a pic or 2....

I think the frame stiffeners would work and would allow me to reattach the spring cup mounting plate that goes on the underside of the frame, but wouldn't allow for reattachment of that other support that runs along the inside of the frame, nor would they fill in the area that is rusted away.

This is not a body off restoration project by any stretch of the imagination, so not going to start pulling off cabs and go through all of that, but do want a truck that I won't have to worry about the rear end falling out. This truck will not be used to tow.

Asking around locally here in south central OK for a shop to bring it to. Any recommendations in the Lawton/Duncan area? I do not have the skill set to weld and this is not a job I will leave to amatuers.

[Sammy]

Inspect closely your trailing arms. If your frame has rust issues I would highly suspect those arms are in need of attention. They usually are in much worse shape, much sooner than the areas you have mentioned. The way they are halved together increases the likelihood of issues.

[mechanicalman]

Originally Posted by Sammy

Inspect closely your trailing arms. If your frame has rust issues I would highly suspect those arms are in need of attention. They usually are in much worse shape, much sooner than the areas you have mentioned. The way they are halved together increases the likelihood of issues.

Good catch!