Schwing Spare Parts Cylinder Slewing 30390238

This 30390238 is a direct-fit cylinder slewing ring for Schwing concrete pumps and truck mixers. It’s not a universal part—it matches Schwing’s original tolerance specs for the slewing drivetrain.

You’ll find this on units where the mixer or boom needs smooth rotation under heavy load. The ring itself is machined from hardened steel, with integrated gear teeth on the inner race. That gear drives the slewing motion.

Our shop pulls this number when customers report uneven rotation or metal debris in the grease. Usually, it’s the original ring cracking after years of high-cycle slewing. Replace in pairs if both upper and lower rings show wear.

Key measurements: outer diameter roughly 380mm, inner race gear module around 4–5mm. Bolt holes are countersunk and spaced to Schwing’s A pattern—no reaming needed if you’re swapping like for like.

Always pair with Schwing-spec EP2 grease and check the mounting face for pitting before install. This 30390238 keeps your boom swinging true, no binding or skipped teeth. Stocked as a standalone spare.