Rear Sway Bar Snapped! Anyone Else Had This?

[gavinc69]

Just went out for a quick spin and found as I reveresed out of my mates drive I heard a clicking from the rear!

On inspection I found the drivers side of the rear sway bar has just sheard through!

I purchased the seay bar kit about 3 maybe 4 years ago, its The Racers Group and there thickest version the 25mm too!

I had to install WEVO rear sway bar mounts because the factory ones ripped but i never thought the 25mm solid sway bar would ever break......

Has anyone else encoutered this?

Think I may go for an Elephant rear sway bar now.


I cabled tied the droplink etc up so I could get home...

[hcoles]

I haven't read of this happening. Your bar asm. is aftermarket, the material and heat treat process could be different than a factory part.

[wildcat077]

Gavin,

Yikes ... good thing you weren't enjoying some spirited driving at the time !
I would say you can't go wrong with Elephant parts as Mr Moreland has a solid reputation
for carrying quality parts and is very active on this forum !

Could have been worse

Cheers!
Phil

[DRACO A5OG]

wow

[gavinc69]

Hi Phil hows it going? Its the weekend so time for a nice pint of the black stuff

Its going to be an expensive month for me....new front pads, bearings and monoballs, after the monoballs went on I found the Weltmiester strut brace didnt work with monoballs, so just ordered Elephant triangulated strut brace........and now need a new rear sway bar LAMO

Think I may just get all my suspension bits from Elephant, at least I know it all works together.

I've just emailed The Racers Group, so I'll see what they say..

[wildcat077]

Hey Gavin,

It's raining here for the next 3-4 days so i'm going to go over my car thoroughly this weekend,i have a two day DE next week so i don't want any surprises.

It's up on stands now so i'm going to go play garage for a few hours
I have a lot of ER stuff on my car and the quality and support from Chuck is next to none !
As far as the Weltmeister strut brace goes,one of my brackets cracked so i welded it up for now because i needed a track alignment and couldn't wait for a replacement but i was looking at Steve Wong's strut brace and it's a nice piece of work.Should one of my brackets crack again i'm strongly considering it ...

As far as the black stuff goes,i will hunt down JJ and claim my Guiness from him ... lol

Good luck with your car,it seems like it's going to get a lot of goodies !

Cheers!
Phil

[911pcars]

Metal fatigue or a flaw in the grain structure.

How long is a sway bar (torsion bar) guarantee? Maybe the Racers Group will provide some out-of-warranty support, but you know about products designed for racing environments. They're a professional org. and race team, not likely to produce shoddy goods.

FWIW:
- 25mm is pretty hefty for all but a late 911 or a track car? What's the rear torsion bar size?
- The great Jim Clark died when the rear sway bar broke on his Formula car. Breakage happens.

Sherwood

[Flieger]

Why is there all that rust around the shiny break? It looks like the bar had a groove to about 1/2 the outside diameter in it????

A hollow bar would be even less reliable.

Very interesting.

[j911brick]

I have seen broken weltmeister bars. As sherwood suggests; what torsion bar are you running? You really should keep things cleaner. Racing parts are not designed for daily driving and a little rust will cause a part to break prematurely.

[RWebb]

rust fissure is just like a stress riser

[gavinc69]

When is ordered the sway bar from TRG I spoke to Austin there and went through the tires/suspension specs and told him the car is just a spirited sunday driver and maybe the odd track day. He said with the cars spec's etc the largest 25mm is fine.

Torsion bars - standard as far as I know.
Shocks - Bilstien Sport
Wheels - 18x10 (rear)
Tires - 265x35x18 (rear)
WEVO engine & trans mounts

Even with cleaning I dont think i'd be able to clean just where its snapped, its up against the drop link and the blue block that bolts to the ARB mount. Unless I disassemble it all and clean it!
Maybe powder coating it would have helped prevent rust.
Still seems strange that what seems to be a high end part designed for the riggers of racing should rust and snap, if thats what caused the problem.

So what is recommended for a mainly street car that wont fall apart?

[jurhip]

I disagree with the comments that racing parts would be more susceptible to this type of failure due to rust/dirt. Metal bars are metal bars, regardless if they are designed for racing (technically metal bars are not just metal bars due to differences in metallurgy and heat treatment, but a "racing" bar is not treated different when it comes to rust prevention). Racing components that are not designed for street longevity tend to be things like bushings/monoballs or very lightweight parts.

My guess, given the picture of the failure, is a manufacturing defect or poor material. Its difficult for me to see, but the failure looks to be more of a brittle type failure - this shouldn't happen with quality material. I'd show it to the manufacturer and see what they say - hopefully they replace it. A proper sway bar should be designed to accommodate the full range of suspension travel the given 911 without reaching into a fatigue zone in torsion or bending (this shouldn't be too difficult for any higher grade steel). This range should be accommodated regardless of torsion bar size. A Smaller than normal torsion bar balance will cause your sway bar to twist more often, but again, the stress levels seen should be low enough with proper materials and design that fatigue failure isn't an issue.

[jurhip]

That said, a friend of mine had his sway bar crack on his BMW 550. So, s&*t happens. Inspect stressed components more often if you are driving hard.

[j911brick]

Originally Posted by gavinc69

When is ordered the sway bar from TRG I spoke to Austin there and went through the tires/suspension specs and told him the car is just a spirited sunday driver and maybe the odd track day. He said with the cars spec's etc the largest 25mm is fine.

Torsion bars - standard as far as I know.
Shocks - Bilstien Sport
Wheels - 18x10 (rear)
Tires - 265x35x18 (rear)
WEVO engine & trans mounts

Even with cleaning I dont think i'd be able to clean just where its snapped, its up against the drop link and the blue block that bolts to the ARB mount. Unless I disassemble it all and clean it!
Maybe powder coating it would have helped prevent rust.
Still seems strange that what seems to be a high end part designed for the riggers of racing should rust and snap, if thats what caused the problem.

So what is recommended for a mainly street car that wont fall apart?

Thats too much sway bar for stock torsion bars.

Race cars are usually maintained better and don't see too much wet weather.

[175K911]

I know of another TRG sway bar that broke, but Mike's was his front bar I think. Looked exactly the same at the break too. But if I'm not mistaken, TRG uses the same bar front and rear, just different hardware. That car was an '87, 23/33 torsion bars, Fox shocks front and rear. Wonder if there's been some metallurgy issues with the TRG bars?

[j911brick]

Originally Posted by jurhip

I disagree with the comments that racing parts would be more susceptible to this type of failure due to rust/dirt. Metal bars are metal bars, regardless if they are designed for racing (technically metal bars are not just metal bars due to differences in metallurgy and heat treatment, but a "racing" bar is not treated different when it comes to rust prevention). Racing components that are not designed for street longevity tend to be things like bushings/monoballs or very lightweight parts.

i don't necessarily disagree with you. I've seen sway bars and t-bars that were totally rusted and didn't fail. But these were stock applications where stress were low. I'm not saying rust caused this failure, just saying rust doesn't help and can promote a failure just like a stress riser.

[jurhip]

PO:
How is your torque arm connected to your sway bar? Given the picture, this could have been slightly loose allowing it to score the sway bar. At some time, or some point in the travel it could have seized up transferring torque through the now weakened, smaller cross section bar. This would be mre likely to fail.

[Todd Simpson]

I saw a friend at the track yesterday and he told me he broke 2 rear sway bars on his '87 Carrera with a 3.6 swap. He was running 28mm t bars in the rear and later upgraded to 31mm. (I used to bottom out on the track with my 28mm bars, btw, and so I went to 30)

I think stock T bars allow so much roll the sway bar is stressed. I'm also pretty sure he mentioned his bars were the same brand.

[dshepp806]

[QUOTE=gavinc69;6021643]Just went out for a quick spin and found as I reveresed out of my mates drive I heard a clicking from the rear!

On inspection I found the drivers side of the rear sway bar has just sheard through!

I purchased the seay bar kit about 3 maybe 4 years ago, its The Racers Group and there thickest version the 25mm too!

I had to install WEVO rear sway bar mounts because the factory ones ripped but i never thought the 25mm solid sway bar would ever break......

Has anyone else encoutered this?

Think I may go for an Elephant rear sway bar now.

Aside from the noted popping you heard, what was felt in the driving of the car (while it was broken)?

Doyle

[Mike Metzler]

I know of another TRG sway bar that broke, but Mike's was his front bar I think. Looked exactly the same at the break too. But if I'm not mistaken, TRG uses the same bar front and rear, just different hardware. That car was an '87, 23/33 torsion bars, Fox shocks front and rear. Wonder if there's been some metallurgy issues with the TRG bars?

As Ed correctly stated, I broke a 25mm TRG bar on my car. Twice. The car is an '87 with 23/33 torsion bars and Fox shocks, just as Ed stated. ~2750 lbs with me in it, and primarily used on the track. I run the bars on the stiff side in front and the soft side in back. In both cases it was the front bar that broke, but the same bar is used front and back. The first bar broke essentially the same place (see below)


The second time it was the weld holding the solid hex plug in the hollow bar:



Did I feel anything? Yes! The first time was in the carousel at Mid-Ohio and I was able to catch the rear end as the front suddenly had more than expected grip. I knew immediately that either the front bar or the linkage for the front bar had broken. The second time was more of a gradual break, as the hex plug still encountered considerable resistance to turning after the weld broke, so the bar "sort of" worked. I spent the full weekend trying to get the car to handle right, and ended up with the front bar set nearly full stiff before I took it all apart and discovered why...

The first bar survived ~10 years of heavy track use, so I felt I had no complaint. The second bar did not last its first weekend. TRG acknowledged it was defective and replaced it gratis.