Author Topic: Has anyone seen a crack in the hood mounting before???  (Read 7565 times)

BarryD

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Has anyone seen a crack in the hood mounting before???
« on: November 25, 2013, 00:04:28 »
Yesterday when Jon, Sal and I attempted to re-install the hood on my 250 SL, we noticed a crack on the driver's side hood mounting area. Don't look at the attached photos if you're eating because they may make you physically sick! I do know that the hood was messed with by a body shop in the 1970's after a fender-bender of some sort, but it appears that they messed with the passenger side of the hood.  Has anyone seen this before? Mr. Bernardi (my car's Godfather) and I are trying to figure out how to get started on this one. Any ideas would be greatly appreciated. - Thanks, Barry

BarryD

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #1 on: November 25, 2013, 00:11:33 »
Oops, the attachments didn't seem to make it!

W113SL

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #2 on: November 25, 2013, 00:49:42 »
There is a very strong possibility that the captivated screws that mate with the ten mm bolts got stuck in their slots and someone attempted the free them up by opening the area up.  Normally this is done by cutting a hole and then plugging it. 

The other possibility is the hood hinge was not lubricated and someone ham fisted individual forced it to move thereby cracking the affected area. 

I have seen all kinds of problems in this area cased by nuts becoming stuck in their slots and hood hinges that were  not regularly lubricated.

Say Hi to Jon for me,

Pete Lesler
W113SL

Rolf-Dieter ✝︎

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #3 on: November 25, 2013, 01:01:01 »
Barry,

I recommend you have this "Metal Stitched" I don't know where you can have it done, however, if you "Google" it you may come across a place that will do it for you. In any case I would not leave it as is the crack will propagate over time then it will no longer be easy to fix. Meanwhile it goes without saying close your hood gently. A picture of "Metal Stitched Repair" is attached. In my early years of engineering we had several castings metal stitched that developed cracks during hydro testing.

Good Luck.
DD 2011 SL 63 AMG and my 69 Pagoda 280 SL

Garry

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #4 on: November 25, 2013, 02:26:20 »
This is not an uncommon problem with the hood being a soft Aluminium however there used to be a repair kit available, not sure if it is still around but suggest try all the regular suppliers.  Any decent welder can repair the crack without going to the stitch method.

Have a read of the following.  Also do a search on hood repairs as there has been some past chatter on repairing and producing your own inner metal bracket.

http://www.sl113.org/forums/index.php?topic=9769.0

Garry
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Melbourne/ Kyneton, Brisbane. Australia
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ja17

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #5 on: November 25, 2013, 05:00:31 »
I fix these all the time. The steel nut cages and the steel nuts are in a hostile environment and are prone to corrode because of the dis-similar metals (aluminum hood and steel nuts and cages).  Once the nuts start spinning, the fun begins. if you ever  have the hood off, run a metric tap in all the holes to clean up the threads of the captive nuts. Also use plenty of anti-seize on the bolts during re-assembly.

I am sure there are many less sophisticated fixes.  I cut the flat nut cage area off the hood frame, rebuild or re-make the nut cages, restore the nuts, aluminum butt-weld the repaired section back in place. The welds are ground smooth. When done right, the repair is undetectable, with no fillers or exposed welds. Takes me about two hours per side on badly damaged ones. No paint damage on the exterior of the hood when done properly.

The quick and easy fix, is to just hole saw a hole in the  hood frame and hold a new nut in place.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
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BarryD

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #6 on: November 25, 2013, 05:13:14 »
Joe, Southern California is very nice this time of year. It's warm, the beaches are un-crowded, and I bet Jon and I could bum a welder somewhere... 
Seriously, thanks to all of you guys for the great information I've received so far.

ja17

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #7 on: November 25, 2013, 05:49:34 »
Hmmm, 17 degrees F. here tonight! I'll be on the next flight out  ;D
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

Rolf-Dieter ✝︎

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #8 on: November 25, 2013, 14:23:52 »
I'm jealous of you fellows on the west coast … look at what I woke up on Sunday morning … spend almost 8 hours cleaning my neighbours and my driveway … some say we had 3 feet of the white stuff … I think it was near 2.5 feet based on the acummulation on my garden table out on the deck :)

Back to the topic … yes there are many ways to fix the crack … main thing is to stop the crack from propagating furtherer (I would drill a small hole at the very end of the crack right now to make sure it will not get any bigger). Joe is of course right to weld it is the way to go, just make sure the welder is qualified for this tricky exercise.
« Last Edit: November 25, 2013, 14:28:28 by Rolf-Dieter »
DD 2011 SL 63 AMG and my 69 Pagoda 280 SL

BaronYoungman

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #9 on: November 25, 2013, 23:01:23 »
DO NOT DRIVE IT!   I had a small crack on mine when I bought it .... It was being towed to my house on a flatbed truck when pow!  let loose cracked through on the one side came off hinges on other flew across road bounced twice ....UUGH!  I think if you look on my original posts from 5 years ago you can see pix of my bent hood.
Bob
Better safe than sorry... I got the repair kit (which I understand is no longer available) and had tig welded on a reinforcement piece besides... I will not be loosing that hood again
Bob "Baron" Youngman
1971 280 SL silver  1 car 0 boxes
1983 500sec Wheeler Dealer AMG Widebody
1985 500sec Paris Autoshow AMG coupe
1994 320sl wifes car
1988 560sec  Japan "Yakuza Car"

Clayton

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #10 on: November 26, 2013, 16:25:55 »
Bob....so dramatic.....and entertaining. Thanks for the warning. I have one of the secure nuts that has gone missing. So, my hood is only secured by 3 bolts. Now, I am scared straight. Barry found a guy in the San Diego area that gives hope towards a cure. I am jumping on that wagon. Thanks for all the input. The hood issue just made the top spot.

zoegrlh

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #11 on: November 26, 2013, 18:24:48 »
My hood had the securing nuts foul up so the fix was to drill a hole about 1" in dia. just above the securing nut holes.  You will need to use the special hole cuting tool for this.  That way it makes a nice hole.  Once you get the old nuts out, you can fit with new nuts.  At the same time you can weld the crack.  Once all is in place, you plug the hole with a rubber plug in the proper size.  Hood looks like it was manufactured that way.
Bob
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Rolf-Dieter ✝︎

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #12 on: November 26, 2013, 19:59:02 »
Bob, The German Forum has a nice write up on this only it is in German … if needed I can translate it.

It can be found here ---> http://www.pagodentreff.de/artikel/kaefigmutterersetzen.html

Once on the site open the PDF File "Ersetzen der Käfigmutter in der Fronthaube"

Translation; Replace the hidden nut in the front hood
DD 2011 SL 63 AMG and my 69 Pagoda 280 SL

BarryD

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Re: Has anyone seen a crack in the hood mounting before???
« Reply #13 on: December 28, 2013, 01:46:41 »
Here is some follow-up on my hood woes:

First, it turns out that I cracked the hood. See my complete confession at http://www.sl113.org/forums/index.php?topic=19796.0.

Second, my hood was weakened because a body shop had cut a hole near the hinge. I assume this was done to repair or replace the captive nuts.

Third, Dave Gallon hooked me up with Hjeltness Restorations in Escondido, CA. They had the expertise to fix the crack, fix the hole, and not damage the paint. Check out the photo.

Thanks to everyone for the help with this one. Hopefully my new post prevents this from happening to anyone else's car!