How to replace bolt o-ring on Walther CP2?

[fhorrigan]

I have been trying to replace a leaky bolt seal on my Walther CP2, without success, and was wondering if anyone who has done this before might have some tips. I have been able to temporarily prevent the leak by periodically applying silicone oil to the seal, but that is becoming less effective.

According to the instructions I have (from a former CP2 distributor who wasn't sure he recalled all the details), the bolt probe (#227) has to be removed in order to replace the o-ring (#226), and to do that one must first remove the rear sight and operating lever (#223).

I managed to remove the rear sight and the screw that holds the operating lever (#53), but the operating lever doesn't budge. The operating lever has a round shaft with a flat side that mates with lever #38 in the probe assembly. I wonder if those parts are locked together in some way. There is no sign of corrosion. I have tried tapping gently on the operating lever shaft from the opposite side of the frame but it doesn't move, and I don't want to force it. There is a youtube video that shows the equivalent procedure for a CP1, where the operating lever seems to pull out without much effort.

Does anyone have any tips for removing the operating lever?

Alternatively, is it possible to replace the o-ring without removing the probe from the pistol?