Canon 600mm F4 Mark II Lens hood Lock Knob

[amistry]

During a photography trip to the Conowingo Dam in Darlington, MD, the locking unit on my Canon 600mm f4 Lens hood failed. The lock (pic below) actually fell out and into the rocks as I was trying to put on the lens hood

Ordered parts from Canon:
XD2-1100-202 - Washer, Retaining (SUS) - Qty 2
YA2-4147-0000 - Knob, Lock - Qty 1
Shipped FedEx for ~$40.

The lock knob was a tight fit. Actually had to use a hammer to lightly tap it (with a washcloth over it) into the locking unit body. Putting in the circlip was also tricky with needle nose tweezers.