RING

551 745 59 RING is typically a guide or wear RING, often found in a hydraulic cylinder or a rock drill piston assembly. Its main job is pretty straightforward: it keeps the piston centered in the bore. Without it, or if it’s worn, the piston would just flop around, scraping the cylinder wall. It also helps maintain a consistent clearance, which is crucial for proper pressure distribution and preventing internal leakage past the piston itself. Think of it as a bearing surface that takes the side load, letting the seals do their sealing job without getting chewed up.

When this RING starts to wear out, you’ll definitely notice some changes in how the system behaves. Usually what happens is the piston starts to wobble a bit more inside its bore. This increased play can lead to a few things: you might see a loss of power or slower response from that cylinder, because the piston isn't moving as efficiently. If it's in a rock drill, you could get inconsistent impact energy, or even a noticeable vibration or knocking sound as the piston bangs against the cylinder wall. Over time, that metal-on-metal contact will score the cylinder, and then you're looking at a much bigger repair bill than just replacing a RING.

When you're swapping one of these out, make sure you properly clean the piston groove where it sits. Any old crud or burrs in there will just chew up the new RING or prevent it from seating right. Also, take a good look at the cylinder bore for any scoring or damage; if it's already scratched up, a new RING won't fix your underlying problem for long. And don't forget a bit of clean hydraulic oil or assembly lube on the RING before you slide it in – helps prevent damage during installation and gets it off to a good start.