Canon 600mm F4 lens lock knob falls out

[Sborg]

I recently bought a the subject lens second-hand and I'm missing the retaining washer.  As a result, the lock knob (the little piece of metal that butts up against the lens to hold the hood in place) frequently falls out as I'm putting the hood on or off.  Has anyone else had this problem?  I've ordered the washer but would like hear if any other users have had the problem and have any tips for inserting the washer into the lock knob.  Thanks.

[Anton2]

Hi, I have the same problem and read about the solution that is mentioned above. But I don't completely understand the text, because English is not my native language. Can you explain the e clip slips on? Maybe you can send a photo of it?

[Sborg]

The e-clips are shaped like horseshoes.  If you hold it with a pair of tweezers, you can force the open end onto the shaft of the screw, as Canonoli stated.  You'll need 2x5 mm clips.  Attached is a picture of the assembly.  The arrow points to the e-clip after I pushed it onto the shaft.  Am also attaching a picture of the e-clips.  You can buy them from Amazon.

[Anton2]

Thank you for the extra information and photo's. 

[Peter]

Thanks!

I have ordered too for my EF800 and EF300.