Lens Hood EF 400 2.8 - Detail photo wanted

I am the happy owner of a EF 400mm 2.8 II, unfortunately the lens hood (ET-161BII) has been repaired and does not work perfectly.
I have just purchased an original locker mechanism, and it would therefore be helpfull if somebody can provide detail pictures of the original locker mechanism.
It would be extremely helpful to get pictures from outside and inside - assembled and dissembled.

The attached pictures shows my own modified version.

Regards
Per

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Here are some photos of the locker mechanism from my ET161B-II. The lens hood has been modified from its original configuration. The original threads stripped out of the mechanism. IMHO Canon did not use the proper screw size for the mechanism.

I repaired it by very carefully removing what was left of the remaining threads with a pin vise & drill. Then, I redrilled all of the way through with a tap drill and cut new oversized threads with a tap. The original screw holes in the hood also had to be drilled oversize for the new larger screws.

Use plenty of Aluminum Cutting Oil to keep the drills & tap from seizing & breaking and go slowly. It is important to make sure that everything is square so the screws are not side loaded when they are tightened. The screws, drills, & tap necessary to make this modification are available at Ace Hardware.

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Here's a side view. Good luck with your repair.

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Hi ScatterCrSport
Thank you for the nice pictures -very helpful

Anyone who can provide 100% original shots?

Regards
Per

Nice work Scatter,.
these locking mechanism were/are a pretty poor weak point, especially on lenses of this era.
On the 200mm f/1.8 I used to own, it all still worked,. but just barely, and even in a functioning set up,. one could see how dreadful the design was and how likely it was to fail. Your solution seems to be a step in the right direction over the original Canon.

I know this is an old thread but just in case someone else does a search... Just picked up a used 300 2.8 from Adorama and the hood lock mechanism was broken. I took it apart and seems the small E-ring clip had failed and wedged itself in the slot. I am trying to get in touch with the Adorama sales guy to see if they want to swap it out but I am sending it to CPS for a clean & check. If CPS does a free fix all will be right with the world.

ChunkyDA wrote in post #17823128
I know this is an old thread but just in case someone else does a search... Just picked up a used 300 2.8 from Adorama and the hood lock mechanism was broken. I took it apart and seems the small E-ring clip had failed and wedged itself in the slot. I am trying to get in touch with the Adorama sales guy to see if they want to swap it out but I am sending it to CPS for a clean & check. If CPS does a free fix all will be right with the world.

If you have no luck, please email me directly: Helen@adorama.com

ChunkyDA wrote in post #17823128
I know this is an old thread but just in case someone else does a search... Just picked up a used 300 2.8 from Adorama and the hood lock mechanism was broken. I took it apart and seems the small E-ring clip had failed and wedged itself in the slot. I am trying to get in touch with the Adorama sales guy to see if they want to swap it out but I am sending it to CPS for a clean & check. If CPS does a free fix all will be right with the world.

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I have seen this exact problem on my own 300 F2.8 and a couple of 500 F4 lenses. I just bought a few different size circlips on E Bay and used the one that was the best fit - much cheaper than sending it back to Canon! I don't know what circlips Canon use but they do appear to be an alloy of butter - they are the worst that I have ever seen!
Unfortunately I cannot remember which size fit best! Just try a few different ones they cost next to nothing.