SEAL KIT

857 716 69 SEAL KIT is what keeps the hydraulic fluid where it needs to be, whether that’s in a cylinder, a valve, or some other critical component on the rig. Essentially, these seals form the barrier that holds pressure in and keeps contaminants out. Without them doing their job, you'd have oil bypassing or just plain leaking, which means lost power and a messy rig floor. It's pretty fundamental to how anything hydraulic actually works.

When these seals start to go, you’ll usually notice it. The most common thing is a slow leak, obviously, but sometimes it’s more subtle. For instance, if this kit is for a feed cylinder, you might see the drill string start to drift a bit when you're not actively feeding, or maybe the boom just sags a little more than it should overnight. That's internal leakage, and it means the seals aren't holding pressure like they used to, leading to sluggish response or even outright failure to hold position under load. You might also hear a bit of a hiss if it's an air seal, or just generally feel like the system isn't as snappy.

When you're swapping these out, the biggest thing is cleanliness – seriously, don't skimp on that. Make sure the bore or rod surface is absolutely clean and free of any nicks or scoring; a new seal won't last five minutes if the surface it's running on is damaged. Always use a bit of clean hydraulic oil or assembly lube on the new seals before installation to help them seat properly and prevent tearing. And don't forget to check the backup rings if there are any; sometimes they look fine but are actually hardened and brittle, which will cause premature failure of your new seals.