Hydraulic cylinder seal kits are used to seal the gap between different parts of the hydraulic cylinder. The function of hydraulic cylinder seal kits is to prevent oil leakage, to assure the working pressure of the hydraulic system, to maintain its power.
Boom Cylinder seal kit is, as the name suggests, fitted into the boom cylinder.
There are regularly three cylinders for the excavator, boom cylinder, arm cylinder, bucket cylinder.
Arm cylinder is the top one, and it's usually be called as top cylinder;
The bucket cylinder is the one that connects and controls the bucket.
Boom cylinder is the one (or the two) near the cabin. Usually, there is one piece boom cylinder for the small excavator under 10-tun; the bigger excavator's two pieces boom cylinders. But there is an exception too when the driver will remove one piece for a special purpose, say at some particular working place, it is convenient to work by one cylinder. Soft remind: all refit job should be operated by an experienced technician.

Part Number: 2438U697R100
Group: Ram Dozer Cylinder Seal Kit
Fit for model: Kobelco SK04-2, K904L, K904, K905LC, SK04L-2, K905