Took my big block 68 barracuda for a quick shakedown run around the block. Its a big block 4 speed car now. Car was fine.

Brought it back and parked it.

Next morning came out and the driver front was sitting on the ground. Started to inspect what was causing this, the t-bar, about 4" back front the lower control arm busted. Snapped.

No visable damge to the bar, just broke. Weird, lucky I wasn't driving when it let go.


Now I have to replace them. I belive these were orginal 1968 /-6 bars. Now I am looking for a recocmendartion on what bars to put in there. This is a street car, but I plan on tracking it as much as I can.

Yes, on a rare occasion they can just snap. My Dad was at a family reunion 50 years ago and a relative was showing off his new Plymouth. As if on cue, one of the torsion bars snapped as they were looking over the car. Rare, but it can happen.

I've seen several that were broken in wrecked cars at the junkyard. They have always been the small slant six bars.
Originals in a race car with a big block ??? I'm amazed that they didn't break sooner.

Yep, they'll snap like that once a crack goes most of the way thru. The crack usually starts with a small scratch or chip and then spreads across the bar over a period of time.

/6 A body bars shouldn't be too hard to find. I think I have a set sitting on the shelf out in the shop.

Never seen a Mopar torsion bar break myself. But I replaced more than a few in Chevy trucks that snapped.
Doug

Every mechanic that did his apprenticeship between 1957 and about 1962 had at least one of those in his toolbox for a pry bar. They broke close to the end at a fairly shallow angle so they were ready made for the job.

Kevin

on my 71 plymouth sat. drove to the track full night of racing drove home and same thing came the next day and it was snapped

had one break in the pits after racing . swapped wheels , packed the boot just about ready to leave just siiting there . BANG .

Tex

I've never experienced a torsion bar break on my cars but Dad had 2. One on his 57 Hemi Desoto and one on his 66 383 Satellite. Both situations over night. Found when heading out to go to work the next morning.

when they first came out in '57 they'd break. i remember my dad pulling out of the driveway and heard a loud crack; bar broke. i don't know when that type of issue was solved but haven't experienced a break. i wonder if todays breakage may be related to offshore materials and manufacturing?

I worked on Mopar police cars for years starting in the 70's. It was in the colder climate of Ct. at the time. They used a lot of salt on the roads during the winter. The salt etched the torsion bars, especially the bent bars of the F body cars of the 80's. Quite a few times walking out to the patrol lot in the cold mornings you would see cars leaning to the side with broken T bars. This was due to the salt getting into the rubber support bushings, etching the bar and causing it to snap. Bill

Back in the late 90's a customer came into the shop during the winter and said he had a frozen shock. He parked his F150 on uneven ground the night before with the RF on a hill. Now the RF was on the bump stop. We drove the truck into the shop and found a broken torsion bar. The next morning the entire front end was on the ground. Over night the LF bar snapped too.

Dads 58 Plymouth station wagon had one break going over a slight rise then down into a depression in the road going about 25 mph. Dealer in town fixed it. That was around 60-61

FF makes them for the OP needing a new set.

http://www.firmfeel.com/default.html

.

I think your original, still unanswered, question was, "do TB's just break?".
I have zero experience with that outcome, but what I have read here for nearly 20 years, the answer is yes, they just break anecdotally when parked, most of the time.
Why, I have no idea, but am very curious. The explanations above do not address, IMO, why its most often when parked.
It might be the ones that broke at speed, put the driver in the cemetery, and we never heard the real reason why they crashed?

Chevy dealer I worked at sold a new Blaser and a torsion bar broke on the freeway so the dealer bought it back and installed a new one. It was resold as "new" and it broke again a second time months later under the 2nd new owner. The dealer bought it back again from the 2nd guy when they realized there was something wrong with it. It sat on the lot for a little bit and then a GM regional rep showed up, looked at it, and then scheduled it to be hauled away someplace. Not sure what happened after that. Could have been put together with an alignment issue and something was in a bind that was making the bar break? Who knows...

Classic torsional fatigue fracture with the spiral break at a 45 degree angle. Happens to people a lot too, especially in their leg bones.

Jcc, I don't pretend to be an engineer. I do know I can be long winded at times so I neglected to mention more of the issues which leaves some things unanswered still. Some of the broken bars I saw had rust or corroded spots in an area of the edge of the crack, suggesting to me that is where the crack initiated.Cracks in steel and fiberglass generally don't stop travelling unless drilled at ends and welded or stitched. This obviously won't work on spring steel. After we drive the vehicle and the engine is warm, we shut it down and all the materials cool and contract,accelerating the cracking process when parked over night. I think this is along the same scenario as why we are told not to rev up cold aluminum rod motors (besides bearing clearance issue). Most of these older Tbars being talked about, I'm sure have at least spotted rust areas over time. I guess what I'm inclinded to believe is that this breakage doesn't just happen all at once. In Connecticut with winter salt, this was the issue with Mopar police cars. I then moved to Florida to work on police cars, not one broken torsion bar in 28yrs. Has to be something to it.In Ct. our fleet parts dept. had to keep torsion bars in stock. That doesn't seem right. Bill

Yes, I agree that the failure process occurs overtime, exempting a hard crash, be it corrosion, fatigue, notch sensitivity, etc and/or some combination.
What catches my attention, is the final chapter of that failure process according to years of reports here, often occurs suddenly, and at rest, which I find hard to explain.
The cool down heat gradient idea is interesting.