Trailer Cracked Frame Repair

[Don52]

My latest welding job was to repair the cracked frame of my friend’s landscape trailer. I believe that the hanger wasn’t welded in the proper position on the frame, which would have allowed the shackle to be vertical in the unloaded condition. This most likely caused the high forces in the hanger, and caused it to break. Ever since the hanger broke, the eye of the spring functioned as a slipper spring and rubbed on the frame. Unfortunately the frame wasn’t thick enough so the eye of the spring eventually dug a slot in the frame. Eventually the slot was deep enough for the eye of the spring to be trapped by the hook that it created in the side of the slot of the frame. When the trailer was loaded it caused the spring to lengthen, which put high forces on the hook of the slot. This caused the metal to be raised on the hook side of the slot and eventually caused the frame to crack.

This repair should get my friend through his busy fall leaf clean up season. In the spring I would like to replace the frozen pins and weld a pipe into the frame to serve as a hanger for the shackle. This will allow the fore and aft degree of freedom that the spring requires, without raising the trailer height too much. The heavy duty axle and truck tires already make the trailer on the high side. A torsional axle might be a better solution to minimize the trailer height, as wrench bender pointed out in a previous post.

http://www.redneck-trailer.com/2009/A/A26-A29.pdf

[Don52]

More Pictures:

[admweld]

Having a 200 dx why not stick weld this with 7018-3/32 seems like it would have been easier/faster then tigging that frame.Don,t know if those sharp corners on your reinforcing plates was a good idea also?Just my opinion,everyone does things different.

[piniongear]

More Pictures:

Nice repair!
I certainly don't expect this one to break again.
Maybe somewhere else, but not at the repair
pg

[Don52]

Having a 200 dx why not stick weld this with 7018-3/32 seems like it would have been easier/faster then tigging that frame.

The frame is only 1/16 inch thick and I have better control with TIG. Plus I didn't want to get sparks on me as I was lying on my back under the frame to weld the horizontal, vertical, and overhead weld positions. It did take me a long time to weld it -- Stick would have been faster.

Don,t know if those sharp corners on your reinforcing plates was a good idea also?

You are right I should have chamfered or used a radius on the corners to reduce the stress concentration.

I appreciate you taking the time to comment.

Don

[Don52]

Nice repair!
I certainly don't expect this one to break again.
Maybe somewhere else, but not at the repair
pg

I agree that it most likely won't fail where I welded it. For my last repair I painted the entire outside of the trailer with the Rustoleum conversion coating and then a glossy black top coat. It held up very well. In some of the pictures you can see some rust on that inside of the frame. I think that I will paint it in the spring to stop this failure mode.

Thanks for your comments,
Don

[piniongear]

I agree that it most likely won't fail where I welded it. For my last repair I painted the entire outside of the trailer with the Rustoleum conversion coating and then a glossy black top coat. It held up very well. In some of the pictures you can see some rust on that inside of the frame. I think that I will paint it in the spring to stop this failure mode.

Thanks for your comments,
Don

Yes sir, I like it!
With a thickness of only .0625, using the DX200 Tig was the thing to do in my opinion.
It sure made a nice clean repair.
pg

[Sberry]

In some of the pictures you can see some rust on that inside of the frame. I think that I will paint it in the spring to stop this failure mode .

Too good,,,,, especially since it looks like the operator just kept driving this long after an obvious problem developed.

[Don52]

Too good,,,,, especially since it looks like the operator just kept driving this long after an obvious problem developed.

You are correct. I brought the formation of the slot to my friends attention several years ago, and suggested that we fix it. We only observed the formation of the crack about three weeks before I repaired it. Once the crack formed it really took off. The frame was entirely cracked on both sides and 25% across the top. There was very little holding the frame together! Once the slot got deep enough the spring must have applied a huge force to the frame to crack it so quickly.

Don

[FusionKing]

Your friend must have a Guardian Angel