Trunk torsion-spring adjustment?

[schuetz1619]

My trunk use to open and close beautifully. Then I got rear-ended and had to replace the lid, the rear panel, and the seal. Now it takes a great slam to close the lid.

 

The torsion spring appears to be gremlin, not the new (BMW not aftermarket) seal. The resistance is really strong before the lid even reaches the seal. Is this adjustable in any way? Mike Self's previous contribution on this question implied that the answer is no, but I'm hoping there might be a solution, somewhere.

 

Thanks.

[Chris_B]

You may need to adjust the lock mechanism. Move the "catch bracket" (the part on the trunk lid) down a bit to loosen up the connection.

Edited February 26, 2023 by Chris_B

[Son of Marty]

You can get some adjustment of the torsion bars by sliding the 2 e shaped plastic bar seperators closer to the trunk center will reduce the tension and toward the outside to increase it.

[schuetz1619]

I gave it a try. Perhaps the result is diagnostic.

 

There is no difference at all in the amount of resistance or in the resistance curve if the clips are in place, removed, far apart, or close together. In all scenarios, the lid stays up when opened fully, and if pulled down, it will drop, lightly, to about 5-6 inches of opening, where it reaches equilibrium. With each inch of additional downward movement, the resistance doubles, and by the time it reaches the latch, solid force is needed to close it.

 

I dom't remember anything like this before the lid replacement of with my other 2002. In both cases there was no drama at all.

 

_____________

 

Just now I looked at the trunk picture of the BAT '74 Alpina tii currently at $60,000. I think I may see the problem. This picture remined me that the bars on my other car crossed each other, creating a long (x). As my "new" trunk lid is set up, the bars don't cross. I don't understand the mechanics involved, but I wonder if this is the key.

[NYNick]

I never removed my trunk lid and replaced the OEM seal after the paint job. I have to slam the living bejesus out of the trunk still, 3 years later.

[jimk]

Adjust the trunk side of the latch catch loop,  a 1/8 inch is all it needs and it won't be seen as an alignment issue on the side trim.  Solved the slamming for me.

[Einspritz]

Needing to slam the trunk is a feature, not a bug.

 

It's German!

 

"They all do that"

[TobyB]

I think there are 2 ways to assemble the springs-

because I had exactly the same thing happen.

 

Before the trunk came off, the lid 'coasted' up a little,

and then would over- center into holding itself up nicely

when you lifted it open.  A gentle push down gave it enough momentum

to relatch pretty easily.

 

Afterwards, stand back, because that sumbitch can now

clock you in the chin when you hit the button.

 

I have yet (24 years later) to try to reassemble it to see if maybe I can make it 

less homicidal.

 

t

 

[71bmr02]

 

I had mine apart a few years back, cant recall why but i must have lucked out and reassembled it properly. i can unlock and it springs up a few inches then i lift it to the open position. closing requires a bit of a slam but it goes first time and the effort might be less if adjusted the lock mechanism but i think i set it up tight to minimize exhaust smells coming in past the trunk seal.  I'll take some pics of the torsion springs and post to this discussion in next couple of days.

[Mike Self]

On 2/25/2023 at 8:22 PM, schuetz1619 said:

Mike Self's previous contribution on this question implied that the answer is no,

I'd love to know if there is an adjustment.  My '73 came with an aftermarket luggage rack on the trunk lid (now gone, with the holes welded up) and its extra weight meant the trunk lid only popped up a few inches when the latch was released.  I fiddled with the torsion bars for quite some time but never made 'em stiffer.  With the rack gone, it now pops up to the same height as my '69.  

 

Did you try lubricating all the moving joints as well as the hinges?  

 

 

mike

[schuetz1619]

Good evening, Mike,

 

I've not taken anything apart or lubricated anything as I will first need to cut, very carefully, the paint seals created in the last repaint in order open up the hinges. It's certainly possible that the painting of the entire trunk underside as a unit has removed the ability of the bars to twist within the hinges, creating more resistance. I suspect the following is involved as well:

 

Just now I looked at the trunk picture of the BAT '74 Alpina tii currently at $60,000. I think I may see the problem. This picture reminded me that the bars on my other car crossed each other, creating a long (x). I believe that this was also true on this car prior to the trunk lid being replaced. As my "new" trunk lid is set up, the bars don't cross. I don't understand the mechanics involved, but I wonder if this is the key.

 

In a new 2002, was the entire, assembled underside of the trunk lid painted as a unit, or was the spring assembly added afterward? Any chance you know?

[John76]

My trunk has two plastic clips on the torsion bars.

Are yours installed the same way as in my pictures?

 

[jimk]

The torsion rods cross to provide the same leverage on the link coming up from the car body.  Not the end to the link in in the top hole when the lid is up (or would be the hole to the rear wnen the lid is lowered) in the bearing block on the lid.

[71bmr02]

Here’s a pic of my 71 trunk torsion bars.  Note the make a long x and the short ends rest against two flats on the trunk underside.  I suspect the location of the plastic clips is critical to keep the center of the x near the center of the car

 

[schuetz1619]

I have both clips, and it makes no diference where they are one the rods—the rssistance and resistance curve are the same, regardless of position. Perpas this is because my rods are not crossed. It appears that I need to fix this first.

Thanks for the observation.