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How to Change the Hydraulic Oil in Various Zinko Jacks

Fluid – primarily hydraulic oil – is the main lifeline of every reliable hydraulic jack, be it bottle jacks, toe jacks, service jacks or anything in between. The hydraulic oil is what transfers the mechanical force from the pump to push a larger piston to do the heavy lifting. Without hydraulic oil, the jack or cylinder wouldn't be able to perform its usual tasks of lifting heavy loads, that’s why it is incredibly important to check the cleanliness and level of the hydraulic oil in your hydraulic jack to keep it working correctly.

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If you want to DIY (do it yourself) here are some quick steps on how to change the oil of your hydraulic jacks:

To begin with, you are going to need a few tools to get this job done . What you will need is a screwdriver, pair of pliers, a small funnel and possibly a small hydraulic pump.

Obtain the correct hydraulic fluid DO NOT USE: brake fluid, motor oil or automatic transmission fluid, those oils were not designed to be used in high pressure hydraulic systems and may damage or corrode the seals as well as the inside of your jack’s oil reservoir due to chemical composition and the additives that can swell the seals and make them leak. We can provide you with replacement oil or you can use an equivalent ISO 150 or AW-32 hydraulic oil.

Once you have your tools ready and new oil it is time to drain and refill the jack:

  1. First thing you need to do is lower or collapse the jack’s ram by opening the release valve, which is a small screw-like bolt located near the jack’s main pump.
  2. Locate the jack’s oil plug and remove it (not to be confused with the other screw with a rubber cover that says DO NOT ADJUST). For floor jacks, most plugs are placed right under the main pump but can be on the main reservoir, when in doubt consult a parts breakdown or call us for help. On bottle jacks the oil plug is almost always located on the side of the cylinder.
  3. Drain the jacks oil completely and operate the pump with the release valve open to clear out those passages.
  4. Refill the jack using a funnel or oil pump, slowly fill the jack with the correct hydraulic oil. Make sure the reservoir is full. For most jacks fill until oil starts to drip from the fill plug. Service jacks often require the cylinder to be lifted to the vertical position and filled until oil starts to drip from the fill plug. Do not overfill the jack with too much oil as pressure will build in the reservoir and cause problems.
  5. When the correct amount of oil has been replaced pump the jack a few times with the release valve still open to get hydraulic oil to circulate through the hydraulic system and push the air out now re-install the jack’s oil plug.
  6.  The jack is ready to be operated, tighten the release valve then give it a few pumps to ensure that the jack is working properly.

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Under constant or heavy duty use it is highly-suggested to check your hydraulic oil frequently for fluid level and condition. Standard oil changes are required every 6 months to 1 year however in harsh conditions and heavy duty use oil contamination can occur quickly and frequently lowering the replacement to every week to one month.

You might also like to check this video out for more visual references.

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