Torsion bars - how long do they usually last?

Having recently experienced a (front left) broken torsion bar made me curious to hear: How long do torsion bars usually last (both front & rear)?

To be on the safe side I had both replaced at the front end, but what about the rears? They have probably been on the car since new in 1984. Do I need to worry?

Imagine a torsion bar collapsing as you're doing 125 mph! That's why I'm curious. I was lucky that my front left torsion bar collapsed while the car was parked in the garage.

[AirCooledExcellence]

Hi All,

I just came across this post by Mikkel, and was wondering about this myself.

How many of you out there have had trouble (or know someone who has) with torsion bars snapping at speed? Just the thought of it scares the s**t out of me, especially when the kids are on board.

Cheers,

Tim.
____________
1983 SC Targa

[john_colasante]

It's very, very rare. If a torsion bar breaks most likely there was some defect or corrosion that caused it to fail.

[GeorgeK]

We had one break in the rear of a 55K miles 1983 930. it was the original bar, and the surface showed no damage (except the break). Luckily at low speed on a mountain pass.
Some racers would polish them on a lathe, as well as the driveshafts, then re-powder coat them, on the basis that every irregularity is the start of a crack. of course if the bar has surface damage, then it can break anytime.

GeorgeK

[89911]

Rare, but after changing mine, I can see how it can happen easily. From sagging original A-arm bushings, the bars were hitting the front steering rack support and chipping the paint. If exposed to salty conditions, this could acclerate the problem. Here is a picture of my bars only after 2 years! True, the larger bar here 22mm will hit sooner then the orginals. Checking them at least every 3-5 years should be done IMHO.

89911

I've just read an e-mail sent to me by a friend (86 Carrera) who complains that his front end creaks like an old horse carriage. Then I come here and see your post. Could the creaking sound be caused by the torsion bars touching something they aren't supposed to, as you've just described? Pure coincidence but I can't help but wonder? Maybe he needs it fixed quickly

[89911]

When this was happening, I can honestly say that I did not hear anything at all. It is very easy to index your settings on a front torsion bar, remove and inspect and then reinstall to check. One step further is to remove the A-Arm bushings, which, after doing it a few times is really not that hard, if the torsion bar is hitting. Chances are his front end is creaking from Poly bushings. Since I changed mine, I have no squeaking at speed, but it does groan when just getting started.

What's the cost of replacing them?

[CamB]

Pelican sells new ones (std or uprated).

It is definitely a DIY job - any idiot (like me for instance) can do it. You should also think about replacing the front A-arm bushings at the same time.

[jess p]

Once had a torsion bar break in my 914. I believe they
usually break when you are going around a turn. If
one ever breaks it won't be long before the other one
breaks.

Ok so torsion bar and bearings are the only thing I need to replace to keep my car safe at 100+ speeds?

[911nut]

That crack looks like it started in the spline area. Scary.
PB

[jphillips-998]

The front torsion bars may be an easy diy, the rears however are a different story. I had new fronts and rears installed, car lowered, sway bars installed and realigned and balanced. It cost $3,500 including parts.

Brings me to point two...things that break at speed. Just got back from Road America in WI. Fast track. Coming out of the carousel at something close to 100. Right sway bar drop link goes bang! and I go spinning. There are concrete walls on each side. Nothing like a 100 mph spin surrounded by cement. I managed to stay off the walls but am pretty frustrated with the sway bars from AJ USA. This is the second break.

What bars do you track guys run?

I am going to ask under it's own topic as well, so you may this post again. Just lettin' you know.

[Tim L]

I had a rear T-bar let go with a bang as I was leaving the pits after my morning tech inspection. This was two days after an open track day with HVR PCA and 250 mi on the track. The car was an 84 911 with 118,000 mi. So I packed up and went home, I'm just glad it went in pit lane and not on the track. The T-bar looked just like the picture posted by GeorgeK.
This gave me a good excuse to upgraded all the T-bars.

Tim

[Gunter]

Will the Tire actually hit the underside of the fender or is there a limit to how far the A-arm or spring plate can travel? Will the shock absorber bottom out before the tire hits the underside of the fender? Any experience with this?

[Superman]

Torsion bar catastrophic failure at 100+ mph is not on my worry list. Or at least it is right next to getting hit by a meteor. You have to be careful in deciding what to worry about.

And no, torsion bars and wheel bearings are not the only things to worry about at triple-digit speeds. At performance speeds, everything has to be right.

[Tim L]

It depends on what tire rim combination you have. I run 255 40 R17 and I had slight rubbing.

Tim

[ChrisBennet]

I would think the front bars would be more prone to this problem. As the end cap wears a groove in the aluminum cross member, the torsion bar is no longer centered in the A-arm tube. It eventually rubs a high point in the tube and starts to rust the torsion bar - and squeak. If you are concerned about this you should check your front bars for rust. The "fix" is to add a little material to the end cap where is rubs the cross member. Search the archives.
-Chris

[widebody911]

Originally posted by jphillips-998
The front torsion bars may be an easy diy, the rears however are a different story. I had new fronts and rears installed, car lowered, sway bars installed and realigned and balanced. It cost $3,500 including parts.

Rear T-bars are not a particularly difficult project. With all due respect, I think for $3500 you got hosed.

[island911]

Originally posted by 911nut
That crack looks like it started in the spline area. Scary.
PB

Nope, it ended there. See how it's undercut. Also the other end of the crack is where the wear (read stress riser) starts.