How to Rebuild a Hydraulic Jack for a Chain Hoist

How to Rebuild a Hydraulic Jack for a Chain Hoist thumbnail
A hydraulic jack can be used for hoisting cars.

A hydraulic jack uses force generated by pressure in lifting heavy loads. It is equipped with two connected cylinders, a large one and a smaller one. By applying force on one cylinder, equal pressure is derived on both cylinders, but because one of the cylinders has a larger surface area, more force is produced. This basic principle is used in lifting heavy loads. A hydraulic jack in the chain hoist enhances its lifting capacity. When a hydraulic jack breaks down, it can be rebuilt instead of replaced since some of the manufacturers offer rebuilding kits.

Things You'll Need

  • Screw driver
  • Pencil magnet
  • Pipe wrench
  • Paper towels
  • Dental pick
  • Jack oil
  • Rebuilding kit
  • Brass cleaner
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    • 1

      Buy the rebuilding kit from manufacturers that make hydraulic jacks. Alternatively, you can order the kit online by sending the model number and the name of the manufacturer to suppliers that are selling the equipment.

    • 2

      Open the jack frame by loosening the jack nuts on each side of the frame. Remove the nuts holding the bottle jack body to the frame. Place the jack bottle and the frame on a work surface. Secure the jack bottle in a vise, remove the ram nuts with a wrench and drain the oil by holding the bottle upside down. Unfasten the oil tank from the jack bottle by pressing against the sides. Release the valve by unscrewing the joints and remove the plunger mechanism using a wrench. Use a pencil magnet to remove the ball or pin for regulating the jack oil flow. Write down the order in which they were removed for reference during assembly.

    • 3

      Clean the passageways of the bottle jack by pressing a paper towel into the cylinder and rotating it using a screw driver. Do this carefully without scratching the sides of the cylinder. Clean any dirt on the jack unit body by pouring clean oil into the passageways and openings. Clean the groove where the tank outer shell is attached using brass cleaner to remove the tough residue.

    • 4

      Replace the seals of the plunger that are broken or old and coat the new ones with jack oil. Clean any dirt or grit from the plunger and install the new seals with the round end first. Install the locking nut and steel washer. Tighten the locking nut after pushing the plunger down until it is in the same position as it was before dissembling the jack. Secure the plunger into the bottle jack base using a wrench.

    • 5

      Remove the old "O" ring from the valve using a dental pick, and install new ones from the kit. Install a conical metal seal with the pointed end going in first and put the valve back in the hole. Use a screw driver to remove the ram seals on the bottom end, and replace them. Coat the interior of the jack cylinder with jack oil and insert the ram. Clean the tank shell and ram nut with a paper towel and jack oil, replace any broken seals and attach the tank shell to the ram nut. Secure the jack bolt to the jack's frame. Use the dismantling procedure you wrote down in Step 2 to put it back together in the right order. Put the handle yoke in place. Use a metallic funnel to refill the jack with jack oil. Test the jack by using it to lift something heavy.

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  • Photo Credit Jupiterimages/ Images

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