Torsion Bar

[penciltester]

Thanks everybody for chiming in. The bar broke off center near the rear hinge. Some have mentioned roof box separation being a probable cause for added stress on the bar. Has anyone reattached their roof box themselves? Or is this a road trip to DMC Midwest kinda thing?

Thanks again everyone.

[opethmike]

Reattachment is perfectly do-able DIY. If you want to replace the roof box, that's an entirely different matter.

[Andrew]

Reattachment is perfectly do-able DIY. If you want to replace the roof box, that's an entirely different matter.

+1 4194's torsion bar failure was the result of roof box separation. The reattachment was not too difficult of a job, but did entail removal of the t-panel and interior headliner. I decided to err on the side of additional precaution and strength; thus, I ended up using a total of 8 5/16 lag bolts combined with fender washers which I placed in a 4 bolt square pattern approximately 2 inches from each torsion bar. Obviously stay far away from the torsion bar passage when drilling any holes. After securely tightening the nuts, I carefully used a die grinder to trim excess from the bolts. BTW I used a towel to shield the rear window from any flying debris while using the die grinder. Upon the reinstallation of the headliner and the t-panel, the repair is 100% undetectable.

I posted the pictures on Today under the topic "4194's Torsion Bar"

Best of luck!

Andrew
4194
5052

[opethmike]

+1 4194's torsion bar failure was the result of roof box separation. The reattachment was not too difficult of a job, but did entail removal of the t-panel and interior headliner. I decided to err on the side of additional precaution and strength; thus, I ended up using a total of 8 5/16 lag bolts combined with fender washers which I placed in a 4 bolt square pattern approximately 2 inches from each torsion bar. Obviously stay far away from the torsion bar passage when drilling any holes. After securely tightening the nuts, I carefully used a die grinder to trim excess from the bolts. BTW I used a towel to shield the rear window from any flying debris while using the die grinder. Upon the reinstallation of the headliner and the t-panel, the repair is 100% undetectable.

I posted the pictures on Today under the topic "4194's Torsion Bar"

Best of luck!

Andrew
4194
5052

That is the EXACT same repair I did on my car. It's a rock solid fix, that I think every DMC owner should consider.

[PJ Grady Inc.]

It turns out the stresses along a circular bar of constant diameter are equal from one end to the other, assuming the torsion loads are only at the ends, as in this application.

Yes, a nick or scratch that's deep enough can create the stress concentration that can eventually lead to a failure at or near the point of the defect.

If you're speaking hypothetically about this, based on a text or your education, I can agree based on my personal experience. Over the years I've seen, heard, or otherwise replaced a couple dozen bars that have broken suddenly. They usually come in to our shop broken but I've had a couple break while sitting in our shop and one break on a road test 25 to 30 years ago. If are you in the car when it happens I can tell you it sounds like a large caliber rifle firing inch's from your head and is alarming to say the least! Fortunately this is extremely rare as it only happened to me once in 35 years while road testing over a thousand Delorean's and many personal/business road trips in my own cars. It's not likely to ever happen to you!

In a side note when an original coolant tank blows apart at its seams under pressure, which has also happened once while road testing, it sounds about like a 22 cal. round going off behind you. It's comparative piece of cake on the alarm scale!

Delorean's, like their creator, tend to make large theatrical noises even in failure mode! Most of the T bar failures are caused by rubbing on the rear hinges but I've seen failures towards the middle and front hinge areas as well. Sometimes it starts as a tiny hairline fissure that shows signs of previous rust once the breakage occur's. Usually but not always it starts where the surface was rubbed, scratched, or otherwise breached which compromises the bar's integrity under load. On all failures I can recall there is always some preexisting rusted crack of varying depth that precipitates the outright failure of the bar. I have never heard of a failure when the door was open. I have some broken bars laying around and if I get the time and can take a clean pic I may try to post one or two of the more interesting "breaks".
Rob

[Rich_NYS]

Cinching a plastic zip tie around the bar where is nears the rear hinge is the best preventative fix for the bar rubbing the hinge. It works well and looks better than an old piece of rubber scrap.

Pat, would you post a pic please? It sounds really simple, but I'd like to see it before I do it so I know I totally have it right.

Thanks!

[Patrick C]

Pat, would you post a pic please? It sounds really simple, but I'd like to see it before I do it so I know I totally have it right.

Thanks!

My car is in storage, but basically open the door, get the zip tie, gently pull the torsion bar away towards you and away from the hinge (it will move), wrap the zip tie around the bar and cinch it, and release the bar. The snug zip tie will now be a protective "layer" around the bar, so to speak, and will prevent the metal bar from ever touching the metal hinge.

[Rich_NYS]

My car is in storage, but basically open the door, get the zip tie, gently pull the torsion bar away towards you and away from the hinge (it will move), wrap the zip tie around the bar and cinch it, and release the bar. The snug zip tie will now be a protective "layer" around the bar, so to speak, and will prevent the metal bar from ever touching the metal hinge.

Thanks Pat, I have a lot of different width zip ties...maybe even one that's close to 3/4". Did you use the widest one you could find?

[PJ Grady Inc.]

My car is in storage, but basically open the door, get the zip tie, gently pull the torsion bar away towards you and away from the hinge (it will move), wrap the zip tie around the bar and cinch it, and release the bar. The snug zip tie will now be a protective "layer" around the bar, so to speak, and will prevent the metal bar from ever touching the metal hinge.

My favorite method of insulating the bar against the rear hinge is to do it with the bar removed and installing a 3/4" piece of 3M heat-shrink tubing or the equivalent. Looks very subtle and rather neat in appearance but requires removal and therefore a bit of expertise to execute but it's de rigour if the bar happens to be out for roof servicing.
Rob

[Ryan S.]

Roof box repair photos.
http://www.deloreanreborn.com/index.php?itemid=96
A couple of years ago, Clint fixed mine.