The backhoe cylinder is the part that allows the operator to open and close the bucket. To apply needed opening and closing pressure, hydraulic fluid needs to flow through the cylinder at a constant level. But, over time the O-rings and seals on the cylinder crack, break and shrink causing hydraulic oil leaks and eventually a loss of the pressure needed to open and close the bucket. To stop this leaking before it causes further damage, you need to disassemble the backhoe cylinder.
Items you will need
Wrench set, open-end
Rope or cord
Hydraulic cylinder cap-removal tool
O-ring removal tool
Seal removal tool
Place the bucket on the ground. Close the hydraulic fluid reservoir lever if the backhoe is equipped with this feature. Turn the engine off.
Remove the 2 hydraulic hose lines that go to the bucket. Unfasten the hose screw-on nuts in a counterclockwise movement using an open-end wrench. Tie the hose ends and hang them in an upward position on the boom shaft. This prevents the hydraulic fluid from spilling on the ground.
Remove the cotter pins with pliers from the locking pins on the cylinder end. Hit the end of the unfastened locking pin with a sledge hammer to move it from its position.
Pull hard on the unlocked cylinder tube and pull it out of position. Place each cylinder end in a vice. Tighten each end so that the cylinder is held firmly and does not spin when you try to unscrew the end cap on the shaft side. Move it counterclockwise to unfasten the cap on the end of the cylinder using a cap-removal tool. Remove the bolts on the end of the shaft if the cap is held in place by bolts. This will vary depending on the backhoe model and make.
Loosen the input valves you see under the cap to remove the piston. These are the valves where the hydraulic fluid flows into the piston. Pull the piston shaft straight out of the cylinder cover. Slightly release the vice and wiggle the tube back and forth as you pull out the piston.
Unfasten the bolt in the center with a ratchet and socket to remove the piston from the upper shaft. Pull the piston from this cylinder.
Visually inspect the piston to look for a scratched cylinder bore or bent piston. These may require you to hone the cylinder bore or to replace the shaft.
Remove the now viewable seals and O-rings from the cylinder with the appropriate tools. Before reassembling the cylinder, replace worn seals and O-rings.