hank:
I think it was TK? who gave us the wise comment in that light’s thread about putting pressure on the lens while turning the bezel, to keep the spacer from lifting and rotating with the reflector as it’s turning.
I opened that light to get the O-ring back where it belonged, not just for the fun of taking it apart.
That might have been me. I discovered that trick on my third attempt to re-seat the O-ring on my BLF A6. I wrote it up for the A6 troubleshooting thread.
Press down on the lens when unscrewing the bezel
KeepingItLight:
If I understand you correctly, you want to unscrew the bezel and remove the lens and reflector.
Be very careful when you do this. There is a white plastic centering ring placed over the emitter. Sometimes when you turn the bezel, this ring, along with the lens and reflector, turn at the same time. This can cause the sharp edge of the centering ring to cut into the dome of the emitter, slicing it, and sometimes dedoming it.
You should press down on the lens with something like the eraser of a pencil when you screw or unscrew the bezel. This holds the lens, reflector, and centering ring in place so that they do not turn when you rotate the bezel.
Another tip is to let the flashlight cool before unscrewing the bezel. When the emitter is hot, its dome gets softer, and it easier to accidentally dedome it.
How to re-seat the O-ring in the head
KeepingItLight:
I was able to get the O-ring correctly seated by carefully putting it in place (which is precarious, but doable). I had to stretch the O-ring a bit to pop it into the small groove where it fits.
Next, I placed the centering ring over the emitter, and stacked the lens and reflector (with O-ring) on top. I lightly balanced the lens on top of the O-ring.
Lastly, I slipped a pencil (eraser first) through the bezel, and gently pressed the eraser down on the lens. By pressing down on the lens, the lens, reflector, and centering ring are held in place so they do not rotate when you screw on the bezel.
Thus, the O-ring was held in place while I slipped the bezel over the lens and screwed it back onto the head.
Hope this helps.