69 Rear Torsion Tube Replacement

FrankT · 10-14-2009, 03:55 PM

Has anyone had any experience (good or bad) with a rear torsion tube replacement?

I have quotes from Stodard and GK Restorations, both very reputable shops, for $3-$5k using the correct frame bench to do the repair.

I was initially considering a DIY repair, but I'm afraid I might screw it up as the alignment is critical and the tolerances are very tight.

I've also found other shops that will do it for $1k (without a frame bench) but I might get what I pay for.

Should I bite the bullet and spend the $5k?

John Schaefer · 10-14-2009, 03:58 PM

Frank,

Are you looking to replace the torsion tube itself, or the metal in the dog legs around the torsion tube and wrapping under the car to the rockers?

FrankT · 10-14-2009, 04:00 PM

Yes, the whole tube from end to end where the spring plate bushings insert. I have an OEM tube which I purchased 12 years ago.

John Schaefer · 10-14-2009, 04:07 PM

I was going to recommend a couple of guys that have done metal work for me rebuilding the area around the torsion tube. I have not replaced the actual torsion tube itself and would not want to recommend you to one of these guys and have them use you as their guinea pig. Sorry.

69911e · 10-14-2009, 04:38 PM

I had my tube and surrounding metal replaced without a frame bench. All worked out fine.

FrankT · 10-17-2009, 04:08 PM

69911e - did you have this done by a shop with experience with this repair? Do you know if they fab'd their own jig?

abisel · 10-17-2009, 06:52 PM

If you try to replace the tube yourself, be prepared for a lot of work.

You would need to fab up some kind of jig to hold the transmission mounts and the spring plate mounts in the proper orientation to the rest of the body.

You would need to grind through three weld beads on each end of the tube. One is outboard and obvious. A second is inboard and obvious. But the third is inside the quarter panel. The only way to get to this third weld would be to grind through the tube walls from inside the tube.

You would most likely have to cut a slit or two on the inboard side of one of the longitudinals just to get the replacement tube in place.

Also, you would most likely have to cut a couple access holes in the rear seat pan so that you can get a good weld all way round the tube in the inboard side of the longitudinal.

The shop manuals have a section on this type of repair.

If you have the tools and feel you can do the job, go for it. Otherwise, spend the extra money and have Porsche do it for you. Not something you would want to trust to someone without a jig. This area is critical to body/suspension alignment.

304065 · 10-18-2009, 05:04 AM

Frank, call Damon Josz at Series900, 603 863 0090. He is in New Hampshire, has Celette benches, is one of a handful of qualified guys who can do major surgery like this, and a damned nice guy besides. Tell him Cramer sent you.

69911e · 10-19-2009, 04:54 AM

No jig was used. I needed 6"-12' of the metal around the tube also replaced so this allowed the curves on the pieces to dictate things would line up. I took the responsibility of verifying allignment based on the old tube.
If you want to be certain of a perfect job I would use a frame bench.

Peter Zimmermann · 10-19-2009, 08:32 AM

Quote:

Originally Posted by FrankT

Has anyone had any experience (good or bad) with a rear torsion tube replacement?

I have quotes from Stodard and GK Restorations, both very reputable shops, for $3-$5k using the correct frame bench to do the repair.

I was initially considering a DIY repair, but I'm afraid I might screw it up as the alignment is critical and the tolerances are very tight.

I've also found other shops that will do it for $1k (without a frame bench) but I might get what I pay for.

Should I bite the bullet and spend the $5k?

I had this job done by Brace's Auto Body in Culver City, CA. The job was done on a frame bench - MANDATORY! - and to help with costs I removed the engine, transmission, rear suspension and brakes (including all lines), the clutch cable, heater boxes, etc. Be sure that whoever you interview is aware that they will have to remove the rear seat bottom sections, cut open the floor above both ends of the tube, in order to properly weld the tube ends all the way around. Measure three times, cut once. Measure three more times, weld once.

My car: '69 912 converted to 2.2L "E".

tomolmsted · tomolmsted's Garage

I am almost done replacing mine. The salvage yard found a good one and cut 6 inch+ sheet metal around the tube mounting. I then cut out the old one. For alignment, I took measurments from other points on the body. It was a tedious - fitting, measuring, cutting, grinding, etc. before I started welding. It's not perfect, but I think it is close. It takes a lot of time. Engine and trans need to be out, plus back seat. If you are ever in Gainesville, I can show you what I did.