Author Topic: Hood Torsion Bar 450 Degree Rotation  (Read 2661 times)

Mpgeslak

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Hood Torsion Bar 450 Degree Rotation
« on: March 12, 2020, 18:28:02 »
I have read a number of posts on this topic but haven’t been able to find a definitive answer.

I have purchased a new hood torsion bar from a reputable supplierr.   When installed the proper way with the small end facing the front, the long side that supports the hood is pointing straight up in the direction of the underside of the hood.  That means to put it under tension I can either rotate it 90 degrees which will not be enough tension, or I can rotate it 450 degrees which seems like too much tension.   The old bar point 180 degrees the other way and thus needed 270 degrees of rotation which seems right.

I have seen earlier posts on this situation, and it seems there are two answers:  either I have a torsion bar that doesn’t work or I need to rotate 450 degrees.  From reading the posts it seems rotating 450 degrees is possible, but is that the  conventional wisdom of this group, or did I buy a part that will not work?

Any advice appreciated.
1967 250SL

WRe

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #1 on: March 12, 2020, 21:24:04 »

WRe

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #2 on: March 12, 2020, 21:25:02 »
... more pictures

Mpgeslak

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #3 on: March 12, 2020, 22:49:06 »
Thanks for the photos.

The issue is that when installed correctly with the small part facing to the front, mine points straight up.

I have attached a photo.  I have re-installed the original one which has a bend, and I have put the new one on top.  You can see from the photo that if I install it with the small part facing forward I can either rotate it 90 degrees (which seems to little), or 450 degrees which seems too much. 

Not sure if I should try to rotate it 450 degrees?  Bit nervous doing that
1967 250SL

WRe

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #4 on: March 13, 2020, 07:52:30 »
Hi,
the force of these torsion bars is not very high and 450° is too much. You should think of the tip that goes into the hood because it can damage the surface if the force is too high.
...WRe

Mpgeslak

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #5 on: March 15, 2020, 16:01:19 »
An update for those interested.   

Figuring that rotating the bar 450 degrees is not a good idea, I got the blow torch out and bent the small end 180 degrees and then re-configured the small end to the right shape for its new position.   The approach worked with no issues and the hood is back on the car and working correctly.

The only obvious potential issue is weakening the bar at the joint where I bent it 180 degrees, but from my testing it seems fine.
1967 250SL

114015

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #6 on: March 17, 2020, 00:48:28 »

Hello Geslak,

We made exactly the same experience like you when I restored my car.
I bought three of these silly hood torsion bars - very very reasonable (back then) from Mercedes,
all the same like yours -
and we were unable to put them in correctly with a correct tension on the bar.   ??? :P :-X

Finally,
we gave up and re-used the old-one - fine.   >:(



Please note:
this doesn't happen too often in real life...
but when Mercedes ordered a reproduction (new production) of a particular part,
sometimes the(ir) supplier just produced 'mess'.
If so and it nevertheless passed the final 'quality control' at DB - bad luck for us as customers then.  :'(
Even worse: the stock is too large and needs to be sold off first (to naive buyers like you and me...). That's why such parts are not expensive....


Achim
Achim
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Mpgeslak

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Re: Hood Torsion Bar 450 Degree Rotation
« Reply #7 on: March 18, 2020, 22:22:07 »
Thanks Achim, good to know I am not alone.  I hope I never have to replace it again!!
1967 250SL