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914World.com _ 914World Garage _ Hinge post Crack

Posted by: obscurity Oct 29 2022, 05:01 PM

Just curious if anyone has seen this damage at the hinges? Is it indicative of some larger problem? Can I just weld it up or does it need reinforcement?

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Posted by: bkrantz Oct 29 2022, 07:32 PM

Can you explore for rust inside the pillar?

Posted by: dlee6204 Oct 29 2022, 08:34 PM

My first thought was someone sat on the door which pulled on this area enough to crack.

My next thought was if your car had enough flex from rust while driving it could generate a fatigue crack over time.

With that being said, I think you could weld it up. You must keep the hinge plate loose though for door adjustment.

Posted by: obscurity Oct 30 2022, 02:26 PM

QUOTE(bkrantz @ Oct 29 2022, 09:32 PM) *

Can you explore for rust inside the pillar?


Maybe with an endoscope?

Posted by: obscurity Oct 30 2022, 03:07 PM

From the back side there is definitely a little rust but it does not look bad.

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Posted by: rgalla9146 Oct 30 2022, 08:32 PM


takes a lot of action to cause that fatigue
Does the door drop when it opens, do you have to lift it to close ?

Posted by: mepstein Oct 30 2022, 08:39 PM

Grind off the paint and get the full story.

Posted by: 930cabman Oct 31 2022, 07:12 AM

QUOTE(rgalla9146 @ Oct 30 2022, 08:32 PM) *

takes a lot of action to cause that fatigue
Does the door drop when it opens, do you have to lift it to close ?


My thoughts exactly, something acted on this section to create this type of stress cracking. Finding the cause is another story, but welding will not fix the problem.

Posted by: Cairo94507 Oct 31 2022, 07:48 AM

That had to be from someone sitting on top of the door. That should weld up nicely. beerchug.gif

Posted by: vitamin914 Oct 31 2022, 08:37 AM

QUOTE(Cairo94507 @ Oct 31 2022, 09:48 AM) *

That had to be from someone sitting on top of the door. That should weld up nicely. beerchug.gif


agree.gif A crack typically will grow perpendicular to the axis of major stress. Looking at the shape of the part it is hard to imagine a force acting perpendicular to that crack from any body flex etc. especially since the mount bends 90 degrees towards the front of the car.

It doesn't look like the car was ever hit into that fender area based on the rust photos.

With someone sitting on the end and/or driving around with the door wide open that is the exact fracture you would expect to see. The moment arm would pivot on the bottom hinge with the top hinge resisting all the force as the the bolt is trying to shear at the holes. That is why the crack is larger at the top bolt. Likely that the bolts were not fully torqued or loose when it happened.

If the door is original to that damage it may have stretched the hole on the hinge and made it oval. Also check to see if the top bolt shown in the first photo is still perpendicular to the surface. If it angles outwards, there is a good chance that force down on an open door did the damage.

Posted by: 76-914 Oct 31 2022, 08:41 AM

QUOTE(Cairo94507 @ Oct 31 2022, 06:48 AM) *

That had to be from someone sitting on top of the door. That should weld up nicely. beerchug.gif

agree.gif

Posted by: mgphoto Oct 31 2022, 10:16 AM

Look at the bottom hinge mounting surface, is it perfectly flat, or is there a dimple at the very bottom, if so the door was forced downward.

Posted by: Jim2 Oct 31 2022, 02:38 PM

Rusty seized hinge pins will cause this type of fatigue.

Posted by: rgalla9146 Nov 1 2022, 07:34 AM

QUOTE(Jim2 @ Oct 31 2022, 04:38 PM) *

Rusty seized hinge pins will cause this type of fatigue.


agree.gif
Excellent point.
Is the top hinge on the door tight ?

Posted by: cholland_ Nov 2 2022, 08:45 AM

Unfortunately dealing with the same issue to a worse extent. The car had been sitting indoors for close to 20 years (much of it without doors installed), so I'm not sure what fatigue it experienced to cause this. Tried simply welding the crack before it was painted, but it reoccurred about a year later.
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Purchased this to replace as much metal as possible and am toying with the idea of adding a reinforcing plate on top.
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Posted by: obscurity Nov 2 2022, 10:29 AM

It seems odd that this would occur with the backing plate between the exposed steel and the loose plate

Posted by: Cairo94507 Nov 3 2022, 09:19 AM

If you add a reinforcing plate to the new piece, add it from the rear if possible. I am surprised this failed again so quickly. How is the metal you welded? beerchug.gif

Posted by: mepstein Nov 3 2022, 09:34 AM

It doesn’t need to be reinforced, just properly repaired. If it came back after a fix, it wasn’t the right fix and there’s probably more at play. You may have to remove the front fender and get to the overlapping metal pieces.

Posted by: obscurity Nov 4 2022, 11:53 AM

I was not talking about adding reinforcement. from the first endoscope image it looks like there is a thick steel "cup" between the visible steel and the threaded loose plate

Posted by: bbrock Nov 4 2022, 01:33 PM

One thought on this is that welds are brittle compared with surrounding sheet metal. It might be better to create a patch that moves the welds away from the chronic stress areas.

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