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356C Teardrop light Screw

Posted: Sat Nov 16, 2019 5:08 pm
by Eric McKinley
I was tightening the rear teardrop light this evening and probably tightened one of the screws a little too much.

I think i threaded the screw a little, it now wont tighten.

I may have to place a slightly larger diameter screw in this one side to allow me to tighten to make a seal with the rubber gasket.

I have looked on the PET and cannot see a size for this screw.

It is called a cross recess screw, part number: 644 631 471 00.

Does anyone know the actual size of this screw.

Thanks in advance.

Re: 356C Teardrop light Screw

Posted: Sat Nov 16, 2019 6:07 pm
by Mike Wilson
I just pulled one off my car.
M5, oval head, countersunk, chrome, Phillips head
12mm overall length; 9mm threaded portion
10mm across the head

If someone has the definitive size with the German numbers, please weigh in.

Mike

Re: 356C Teardrop light Screw

Posted: Sun Nov 17, 2019 12:19 am
by Hugo Karasawa
These are pictures of the original oval head screw.
It is an M5 screw, total length 13.5mm, it is an M5 x 12mm oval hrad.
Most probably you stripped the threads on that side, you can repair it using an M5 rivnut (pictured), similar to the nut used in the light housing.
Or use some solder to repair the threads.
oval head screw 01.jpg
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oval head screw 02.jpg
oval head screw 02.jpg (136.81 KiB) Viewed 1430 times
oval head screw 03.jpg
oval head screw 03.jpg (205.44 KiB) Viewed 1430 times
oval head screw 04.jpg
oval head screw 04.jpg (136.2 KiB) Viewed 1430 times

Re: 356C Teardrop light Screw

Posted: Sun Nov 17, 2019 2:51 am
by Eric McKinley
Mike, Hugo, thank you very much for the replies and taking the time to remove the screw and measure.

I believe I stripped the threads in the light section not the actual screw itself.

Placing an oversized screw probably is not the best option, repair would be better.

You mention solder, can you elaborate a little, also are there any other ways to achieve a fix that others may have used in the past.

Re: 356C Teardrop light Screw

Posted: Sun Nov 17, 2019 11:55 am
by Mike Wilson
I believe Hugo is suggesting drilling out the threaded portion on the tail light to insert a 5mm Rivnut. Another option might be to fill in the threaded portion with solder or JB Weld and then drill and tap it back to 5mm.

Mike

Re: 356C Teardrop light Screw

Posted: Sun Nov 17, 2019 12:06 pm
by Eric McKinley
Mike, yes your right, I will look at that option, thanks Hugo.
I wasn’t aware that JB weld was hard enough to drill and tap, another definite option.

Thanks guys.

Re: 356C Teardrop light Screw

Posted: Sun Nov 17, 2019 1:01 pm
by Hugo Karasawa
Yes, that is what I meant. There is not much force in that place, it is just to hold the chrome bezel.

Re: 356C Teardrop light Screw

Posted: Sun Nov 17, 2019 1:14 pm
by Bob Kittel
In my opinion Marine-tex makes the best fillers for metal repairs. Use the Marine-tex gray and you can get it a marine dealer or Amazon. Threads, taps and machines like metal. Maybe overkill for this repair but nice to have in the tool box.

Re: 356C Teardrop light Screw

Posted: Thu Nov 28, 2019 9:42 am
by Eric McKinley
I used JB Weld, leaving it for a few days to fully harden.

I drilled and tapped it to 5mm, and inserted the screw.

I could not pull the screw back out, as before, so a workable solution.

Many Thanks for all the help and advise guys.

Re: 356C Teardrop light Screw

Posted: Thu Nov 28, 2019 12:44 pm
by Mike Wilson
Congrats on solving the issue, Eric.

Mike

Re: 356C Teardrop light Screw

Posted: Mon Dec 02, 2019 10:26 pm
by Thomas Sottile
If you can get a 5mm oval head screw about 1/2 inch long or 5/8 long you can make your own

Re: 356C Teardrop light Screw

Posted: Tue Dec 03, 2019 12:51 pm
by Thomas Sottile
good solution