ROD SEAL

550 360 90 SEAL, ROD is basically the main barrier keeping hydraulic fluid contained within the cylinder as the rod extends and retracts. It’s crucial for maintaining pressure and preventing external leaks, which, let's be honest, nobody wants. More than that, it also helps keep contaminants like dust and water from getting *into* the cylinder and messing up the internal components. It's a simple part, but it does a lot of heavy lifting in terms of system integrity.

When this seal starts to go, usually what you’ll notice first is a weeping or outright leak around the rod itself. It might just be a little sheen of oil at first, but it won't be long before you've got a steady drip or even a stream. Beyond the obvious mess, a failing ROD SEAL can lead to a noticeable pressure drop in that cylinder, making the function sluggish or causing it to drift under load. You might also see the cylinder just not holding position like it used to, or it takes more effort to move it.

When you're replacing one of these, make sure you properly clean the rod and the gland housing. Any nicks or burrs on the rod will just tear up the new seal in no time, and then you're back to square one. Don't forget to check the wiper seal, too; it often gets overlooked, but it's the first line of defense against external crud. A little bit of clean hydraulic oil on the new seal before installation helps it slide in without damage and seats it properly.