Do early sway bars/torsion bars have expiration date?

[Burint]

Hi,
I am in the process of buying the 1967 SWB. RHD.
The suspension still be in an original set up.
Beside those replacable rubber bushings and shocks,
would you replace the torsion bars and the sway bars?
Does the metal loose the stiffness in 40 years?
Thank you
Burint
Bangkok,Thailand

[ttweed]

Originally posted by Burint
Beside those replacable rubber bushings and shocks,
would you replace the torsion bars and the sway bars?
Does the metal loose the stiffness in 40 years?

How many miles on the car? It's not really age alone but duty cycles that can fatigue the metal. Any corrosion can reduce the life of the bars as well. When you replace the bushings, inspect the bars carefully for rust and/or cracking. If they are in good condition, they probably can be reused, but keep in mind that this is an excellent opportunity for an upgrade to the suspension as well, depending on your goals for the car.

TT

[john70t]

Unless they were coated with grease from the factory, they probably have some rust starting on them. Also, even when not driving, the weight of the car is resting on them.

People have reported the torsion-bars breaking suddenly. I would replace the torsion bars with the same diameter.

[Walt Fricke]

Steel doesn't lose stiffness. A torsion bar may twist a bit with age and use (so the car could sit a bit lower), but its spring rate will remain constant. And steel, if stressed below its elastic limit, can go on and on almost indefinately.

Until it snaps, that is. However, there is no easy way to tell if that will happen to the bars in this car. Plenty of torsion bar cars are out there being driven with a whole lot of duty cycles on the bars. But you can deal with that by inspection if you decide to replace the bushings. And even if there is some rust you might be able to clean that up and repaint and reinstall with a protective coating of grease.

Or just replace it if this worries you. They are not all that expensive (especially compared with other things that may need attention on a 40 year old car).

Walt Fricke

[Burint]

Hello ,
This car was registered here in 1967 and could be one of the first 5 Porsches imported here according to the police record.
The car hasn't been driven once in the past 17 years.
Thanks for your advise on the torsion.
Burint

[Tim K]

Rear torsion bar snapped. Taken from an 83 SC. The bar had no signs of corrosion or wear (ie. from worn bushing). Part of it was sectioned and analyzed for a metallurgy project at school. The notch was made to help orient of the pieces.





Nothing was found to help determine the cause of failure.

Tim K