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Securing a loose screw on the EF 100-400ii

Started 3 months ago | Discussions
Swervin Mervin
Swervin Mervin Regular Member • Posts: 309
Securing a loose screw on the EF 100-400ii

I've got an annoying loose screw on the mount on my 100-400 that works it's way loose every few weeks. I tighten it up and it always comes loose again.

I've read up and people have suggested Loctite Blue

Just wondering if anyone can confirm if this is the right stuff?

https://www.amazon.co.uk/dp/B07BP9JPC9?th=1

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BirdShooter7 Veteran Member • Posts: 9,134
Re: Securing a loose screw on the EF 100-400ii
2

I’ve used the blue loctite to solve this problem with success and was still able to remove the screws later.  I definitely don’t recommend using the red loctite as it’s very difficult to remove the screws if you ever need a repair.  I made that mistake once and had some very uncomfortable time with the heat gun to get the screws out.

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Wade Oram Junior Member • Posts: 32
Re: Securing a loose screw on the EF 100-400ii
1

More likely to be this one: Loctite Blue 242

Andy01 Veteran Member • Posts: 5,191
Re: Securing a loose screw on the EF 100-400ii
1

Loctite 243 (Blue) is the one you want (which I believe is what the OP linked above).

242 is the "older" version of 243, and is very slightly weaker, and less oil resistant, meaning that the threads have been be cleaned thoroughly for it to work properly. This may, of course, not be a problem on a camera lens, so I am sure that 242 would work as well - if it is still available.

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Arthur Stanley Jefferson Contributing Member • Posts: 809
Re: Securing a loose screw on the EF 100-400ii
3

Clean the screw, blue thread lock, and use a JIS driver tool of the right size. They are slightly different from Philips

https://www.ifixit.com/products/jis-driver-set

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Steve Balcombe Forum Pro • Posts: 15,582
Re: Securing a loose screw on the EF 100-400ii
1

Swervin Mervin wrote:

I've got an annoying loose screw on the mount on my 100-400 that works it's way loose every few weeks. I tighten it up and it always comes loose again.

There's something about the 100-400L II - I've had exactly the same problem with the same lens.

I've read up and people have suggested Loctite Blue

Yes, Loctite 243 as mentioned by another poster. Works perfectly.

Just wondering if anyone can confirm if this is the right stuff?

https://www.amazon.co.uk/dp/B07BP9JPC9?th=1

I don't recognise that packaging, but search for Loctite 243.

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