How to Repack the Cylinder Shaft on a Backhoe Bucket

Written by kevin mclain
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The bucket on a backhoe is designed to scoop and dump dirt and other materials. The bucket is opened and closed by a single hydraulic cylinder. Hydraulic fluid moves in and out of the hydraulic cylinder tube to cause the pressure needed to open and close the bucket. Over time, the seals and O-rings on the hydraulic cylinder can become damaged and cause hydraulic oil to bypass the cylinder and leak out of the cylinder tube. Once the cylinder tube begins to leak, repack the cylinder shaft with new seals and new O-rings to stop the hydraulic leak.

Skill level:
Moderately Challenging

Things you need

  • Safety glasses
  • Protective gloves
  • Wrench set, open-end
  • Bungee cords
  • Pliers
  • Sledge hammer
  • Table vice
  • Hydraulic cylinder cap-removal tool
  • Seal removal tool
  • O-ring removal tool
  • Hydraulic cylinder packing kit
  • Hydraulic fluid

Show MoreHide


  1. 1

    Lower the backhoe bucket to the ground. Turn the engine off and close the hydraulic fluid reservoir valve, if it has one.

  2. 2

    Remove the two hydraulic lines from the bucket cylinder tube with an open-end wrench. Turn the screw-on nuts of each hydraulic line counterclockwise to loosen and remove. Hang the lines up on the boom shaft with bungee cords to prevent anymore hydraulic fluid from leaking onto the ground.

  3. 3

    Locate the locking pins on each end of the hydraulic cylinder tube. The locking pins secure each end of the tube to the bucket and the boom. Remove any cottar pins from the locking pins with the pliers. Tap the ends of each locking pin with a hand-held sledge hammer until the locking pins are out of each tube end.

  4. 4

    Grab the hydraulic cylinder tube and pull it out of the cylinder brackets with your hands. Place the hydraulic cylinder into a table vice. Tighten the vice around the end of the tube closest to the tube cap. Tighten the vice around the tube just tight enough to prevent the tube from spinning.

  5. 5

    Unscrew and remove the end cap on the end of the cylinder tube with the cap-removal tool. Turn the cap counterclockwise to loosen and remove. Pull the cap off the end of the tube and place it on the table. Loosen the two hydraulic input valves that the hydraulic lines connect to with an open-end wrench. This will release any hydraulic fluid pressure out of the tube and make it easier to remove the cylinder from the tube.

  6. 6

    Grab the cylinder from the end of the cylinder piston and pull it straight out of the tube. Turn the cylinder back and forth as you are pulling it out of the tube. Place the cylinder on the table. Loosen and remove the piston from the cylinder by removing the bolt in the centre of the piston with a ratchet and a socket. Separate the piston from the cylinder.

  7. 7

    Remove the seals and the O-rings from the cylinder individually, starting at one end of the cylinder. After each seal and O-ring is removed, replace them with a new seal and O-ring before moving on to the next seal and O-ring. Once all of the seals and O-rings have been replaced, pour fresh hydraulic fluid over the new seals, O-rings and the cylinder. Rub the hydraulic fluid into the seals and O-rings and over the cylinder with your hand.

  8. 8

    Reattach the piston to the cylinder with the single bolt. Tighten the bolt with the ratchet and socket. Slide the cylinder back into the tube until the piston meets the entrance of the tube. Gently push the piston into the tube to prevent any damage to the new seals and O-rings. Screw the end cap back over the end of the cylinder tube. Tighten the cap with the cap-removal tool. Tighten the hydraulic input valves with the open-end wrench.

  9. 9

    Remove the hydraulic cylinder tube from the vice and reinstall it onto the bucket and the boom with the locking pins and cottar pins. Screw the hydraulic lines back onto the hydraulic tube and tighten the lines with the open-end wrench.

  10. 10

    Open the hydraulic fluid lever to release the fluid from the reservoir to the cylinder. Start the backhoe and move the bucket up and down. Inspect the hydraulic tube for any leaks while the bucket is being moved. Lower the bucket back to the ground and turn off the engine.

Tips and warnings

  • The seal seats are designed to specifically fit the seals only. The O-ring seats are specifically designed to fit the O-rings only. This prevents the seals and the O-rings from being installed into the wrong seat.
  • Each hydraulic cylinder requires its own hydraulic cylinder packing kit. Make sure that you have the proper cylinder information when purchasing the new packing kit.
  • The hydraulic cylinder packing kit comes with all of the O-rings and seals needed for repacking the cylinder.
  • The hydraulic cylinder packing kit and the hydraulic tube cap-removal tool can be purchased from most heavy equipment parts stores or hydraulic parts stores.
  • Do not over-tighten the vice around the cylinder tube. This can result in damage to the tube.
  • Wear safety glasses when removing the hydraulic lines from the cylinder tube.
  • Wear protective gloves if the cylinder tube is hot.

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