When you're pulling this with your TDI...
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and then at 70 MPH you hear a BANG and feel a strong jerk, the result is likely a blown tire like this...
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but what you don't expect is for it to break your hitch in the process...
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Safety chains save the day.
If you look close at the crappy picture above, you'll see that at the top of each piece at the break, there's a slight darkened depression in the middle. This is an area of high cycle fatigue that has been cracked for a while and has started to corrode which is why it's darker. This is on the top side of the bend and is in tensile when pulling the trailer/compression in breaking
At the bottom of each piece if you look close and use your imagination, you'll see a ~0.050" tall strip of very smooth/fine area. This is another area of high cycle fatigue that has not been cracked for a while as it's still bright and clean. This is on the bottom side of the bend and is in tensile when breaking with the trailer/compression when pulling.
The other 95% of the 1/2" x 2" drawbar was low cycle fatigue, sudden failure as it's very rough and "torn"
I magnafluxed/glowed the rest of the cross bar for any other signs of fatigue and didn't find any.
It used to look like this...
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The new and improved one looks like this...
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It's a pair of 1.5" x 0.125" wall box tubes with a 3" x 0.625 top plate to mount the ball.
It needs a coat of paint and a 1" hole punched in for the ball, but otherwise I like how it looks.
It should be much stronger in the side to side direction (think wagging trailer) and less suceptable to fatigue with the large smooth radius on the inside of the bend. I tacked the box tubes together then made 4 cuts through the 3 sides leaving the inside corner un-cut. I then bent the tubes to fit the curve of the back bumper then welded the now wider gaps full so it's like a formed piece of 1.5" x 3" box tube with a 1/4" thick reinforcing web in the middle.
I'll try and get some pictures of it on the car once I get it painted and mounted up.