John Deere manufactures personal lawn appliances as well as commercial-quality outdoor and farm equipment. Many John Deere machines use moving parts that are controlled by actuators, or hydraulic cylinders. Rebuilding these cylinders entails completely disassembling the cylinder and resealing every component with new seals. Exact rebuild instructions will vary according to each particular cylinder. Each cylinder also has its own unique seal kit with every seal that needs to be replaced during cylinder overhaul.

Open Wire Lock Cylinder

Open the cylinder ports and drain all the hydraulic oil. Extend the rod.

Clean and dry the cylinder and clamp it into a bench vise at its base.

Lift the lock ring out of its slot with a screwdriver, then rotate the rod end guide with a spanner wrench until it faces the same direction as the end of the lock ring. Pull the lock ring out of its slot. Skip this step if the cylinder secures with a snap ring.

Open Snap Ring Cylnder

Open the cylinder ports and drain all the hydraulic oil. Extend the rod.

Clean and dry the cylinder and clamp it into a bench vise at its base.

Remove the external snap ring with snap ring pliers, and drive the rod guide into the cylinder past the snap ring groove with a wooden dowel. Clean any debris from the snap ring groove, and install the filler ring from the cylinder seal kit into the groove.

Disassemble Rod End

Pull the rod end from the cylinder barrel and secure it in a soft-jawed vise.

Unscrew the piston nut, and remove the piston and rod guide.

Remove all the seals and rings from the piston and the rod guide. Remove and discard the filler ring from the snap ring groove. Inspect the piston, rod guide, piston rod and inside of the cylinder for nicks and scratches. Smooth any rough areas with an emery cloth, and replace any parts with deep gouges.

Clean the inside of the barrel and dry it with compressed air.

Reassemble

Install new seals onto the piston. Different cylinders may have different seal configurations, so install the new seals in the same configuration as the old seals were installed. The cap seal will probably be the last seal to install on any John Deere cylinder piston. If the cap seal is stiff and difficult to install, soak the cap seal in hot water for five minutes to make it more flexible. Then install it the seal quickly.

Tighten a hose clamp around the piston to shrink the cap seal if it is loose or if it will turn on the piston. Protect the seal by placing a shim between the screw portion of the clamp and the cap seal. Waiting eight hours after installing the cap seal onto the piston will also allow the piston to shrink.

Install new seals and rings on the rod guide.

Place the rod end back into a soft-jawed vice and install the external snap ring, rod guide, piston and nut. Lock wire-type cylinders do not use an external snap ring. Tighten the piston nut to its specified torque.

Tighten a hose clamp around the rod guide's internal snap ring, and then loosen it a little. Insert the rod into the cylinder until the internal snap ring is secure. Pull the rod outward to ensure that the snap-ring is engaged.

Install the external snap ring with snap ring pliers, or install the wire lock ring by inserting it into the lock ring hole and turning the rod guide until the lock ring is seated.