Torsion Bar Tube Failure

I was driving along and my rear suspension just collapsed. The torsion bar tube just failed completely in the middle. I was not aware of this even being possible. Has anyone seen or heard of this before? I need a center section of a tube if anyone has one or knows where to get one i.e. from a parts car somewhere :(

Attachment 601708

Usually corrosion damages the tube ends but the hard bushes (Poweflex that you seem to have) may increase the load in the tube as well. New part is available at least from Dansk. Will require major work on the chassie.

JP Group No.: 1682001800
OE No. 591053-0

Attachment 601709

I am dealing with the same thing. Mine is more of a general corrosion issue though. Restoration Design also sells a replacement. I hadn’t seen the dansk version and I like that it has the brackets already welded on.

Edit: the dansk one might be a LWB while the restoration design one is a SWB version.

https://www.restoration-design.com/store/product/PP280T

I’ve seen this 2 times - one was many years ago with a 68S targa that was driving on dirt roads before it bought it. The seller said he hit a bit of a jump and heard a strange noise when he landed. We were able to merge the tube back together and put a big metal band aide over it, not what most would do today but the whole car was $20k back then.

I also have a 67 targa with a broken tube now, I haven’t gotten into it yet but it is broken in the same place as yours. Underside of my car looks the same - previously rusty with some type of undercoat smeared all over it to hide the true condition.

Most likely water got into the tube and rusted it a bit. The decision now is replace the entire tube or the middle section of it. My metal guy, who almost only works on Porsches said you can replace just the center section if the rest of the car isn’t too rusty, to weld the whole diameter of the tube he recommends cutting a window in the rear seat floor to weld the top portion of the tube. Post pictures of the repair, it’s a rare repair to do.


Of course if you are running huge rims/tires, aftermarket torsion bars, racing bushings or other higher stress parts then you will get more strain on a chassis.

Quote:

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Originally Posted by VintageExcellen

to weld the whole diameter of the tube he recommends cutting a window in the rear seat floor to weld the top portion of the tube.

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this is also what the factory repair manual suggests...there are even nasty pictures of such a surgery shown in it.

and btw this disease isn`t that seldom as one may think..many owners simply don`t know it yet .hairline cracks are also quite freqently seen around the welding that joins the tube with the splined insert that accepts the torsion bar..
next time you crawl under your car have a very close look...and possibly what you`ll get to see will ruin your day

Quote:

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Originally Posted by VintageExcellen

I’ve seen this 2 times - one was many years ago with a 68S targa that was driving on dirt roads before it bought it. The seller said he hit a bit of a jump and heard a strange noise when he landed. We were able to merge the tube back together and put a big metal band aide over it, not what most would do today but the whole car was $20k back then.

I also have a 67 targa with a broken tube now, I haven’t gotten into it yet but it is broken in the same place as yours. Underside of my car looks the same - previously rusty with some type of undercoat smeared all over it to hide the true condition.

Most likely water got into the tube and rusted it a bit. The decision now is replace the entire tube or the middle section of it. My metal guy, who almost only works on Porsches said you can replace just the center section if the rest of the car isn’t too rusty, to weld the whole diameter of the tube he recommends cutting a window in the rear seat floor to weld the top portion of the tube. Post pictures of the repair, it’s a rare repair to do.


Of course if you are running huge rims/tires, aftermarket torsion bars, racing bushings or other higher stress parts then you will get more strain on a chassis.

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i dont know yet if my issue was related to internal rust or fatigue. I do drive my car quite hard but nothing like a track car would see. Oddly the tube failed when I was driving rather slow for once with the Mrs in the car as well. I wont know until I get to cutting it out. Im hoping that I just need to replace the centre section, that said it is still a big job including cutting the seat bases out. I guess I know what I'll be doing this winter... :(

This is a no rust car I wanted a turbo tube put in. Sleeves were installed on the inside and when the tube was put in place, the sleeves were knocked into place. Holes had been drilled in the existing and turbo tube and then plug welded. Then the tube was welded all around. If your existing tube is structurally sound, this is an option.

https://forums.pelicanparts.com/pors...r-project.html
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"It's as if the torsion tube is the very first part they started with when building the car. They just put it there, suspended in space. Then they built the rest of the car around it.

Everything else on the car is a sub-assembly of one sort or another. They all just bolt on. Engines, Control arms, Struts - you name it. Everything else is just hanging on the car, and for the most part can just be unbolted.

But not the torsion tube. It is truly buried inside the chassis, welded to multiple layers of metal in the box sections. Then layered thick beneath one sub-assembly after another."

I do have an original tube from a parts car. Sensitive & easy pricing !!! PM if interested.
Best.

I think I have managed to source a replacement tube section for now. What I dont get is, with all the hundreds of threads about people fitting bigger engines and fatter bars in these cars (things I have not done), I have never seen anyone mention or discuss at all the possible need to reinforce the torsion bar tube, or to inspect it for cracks or anything like that.