42043 Mercedes Arocs Truck Crane Turntable Sticking I have recently found that the turntable of the crane has been sticking when turning! Having taken apart the crane and investigated the issue, it seems to be the interplay between the turntable's teeth and those of the small black cog: they are not meshing smoothly! The cog moves nicely when turning the turntable, but is stuttering and jamming the other way round (the more useful way)!

Any help would be appreciated! 

P.S. any tips on lubricating the yellow pistons?
This is a known problem with that gear combination. It's a flaw with Lego's design of the bevel gears. See this discussion on the EuroBricks forum.  

Bevel gears are typically designed to fit with only one other size of bevel gear. Specifically, the cone-shaped pitch of each gear needs to intersect with each other at a single point to ensure smooth operation.

All Lego bevel gears are intentionally designed with a 45-degree pitch so that any gear can mesh with any other. This means that only bevel gears of the same size can actually mesh perfectly, although in most gear combinations, the loose tolerance means the incorrect pitch isn't really noticeable.  

However, in extreme cases like the 12-tooth-bevel to 60-tooth-turntable in the Arocs, the gear pitches are so mismatched it creates an extremely "noisy" or "sticky" effect.