Just a passing thought.

You're not banging on that SK while it's on a firm surface are you?

I think the key is to let it move. I hold the pedal in one hand and whack the uprights with the other, letting the pedal recoil away from the impact. I feel the acceleration forces are what pops the covers off.

Interesting, I was bracing it agains my work bench. I'll try it while holding it in my hand next.

Hasn't failed me yet.

Hold the upright you are striking open palm, with the cap facing up.

Of course, if not using a rubber hammer. wrap the post in some cushioning material a few layers thick. Strike about 3/4 of the way up to the cap.

May take a few raps of increasing force. But, be aware that the assembly you are hitting IS a casting, and can break. So quick sharp raps, not sledgehammer blows are key.

P.S. May also help to trace around the cap with something like an exacto knife to remove any grunge that may be preventing it from popping off.

This is the way I did it too. Good point.

/Magnus