Lube-a-matic II die disassembly

[LaneP]

I have an RCBS Lube-a-matic II I've been using on and off for many years and recently noticed I'm getting more lube blow-by than normal. I'm in the process of trying to get new o-rings for my .358 die (email to RCBS, web research), as the original outside o-ring is looking its age.

I would think there is also an o-ring on the inside piston, but can't find any info on this so far, including on the RCBS site. Have you ever removed the inside piston from one of these dies (and which end it comes out)?

Thanks in advance for your help.