I know that, but how does it shake? As you can see in my video of the lego brunswick a2, I have tried my best of getting it to work. Maybe there is a better way of making it work?
As shown at 0:07, what makes the ball "squeak" in the lift rods? Is it slippage at top of ball lift? Is it the shiny ball surface? I notice that sound doesn't happen all the time but just with certain A/ A2's and maybe certain balls.