When should you change the oil of a hydraulic jack?

Each engine hoist will eventually need the oil to be changed of the hydraulic jack, how often depends on the usage frequency of the hoist. How to know when oil of the jack needs to be changed?

First of all, if you notice that the ram starts to slowly lower under a load. This may be instantly after you have lifted a load or after some period of time, so if you want to leave the engine hanging on a hoist (which is not recommended, use an engine stand for this job), make sure that the hoist is in a perfect working condition, so you don’t find the engine lying on the floor at the next day. Also, your jack may need an oil replacement if the ram cannot be fully extended. Both of these situation can be caused either when oil in the cylinder is dirty or contaminated, or there simply isn’t enough oil in the cylinder due to an oil leak or other factors. Remember, if purchasing a used engine hoist, make sure that it has a proper oil level, or the hoist might not perform well.

What type of oil should be used?

This is important, you should only use a hydraulic jack oil, which is specifically made for usage in jacks of engine hoists and other tools. Make sure to purchase high quality, good grade hydraulic oil. Don’t use transmission fluid, motor oil, brake fluid or other type of oils that are not made specially for hydraulic jacks and also don’t mix different types of oils. If you don’t know, which type of hydraulic jack oil is suitable for your engine hoist, take a look at the manual of the hoist that usually indicates recommended products for a specific hoist.

How to change oil of a hydraulic jack?

Here are the basic steps of changing oil of a hydraulic jack:

  1. Open the release valve to lower the ram to the lowest position;
  2. Unscrew the hydraulic jack and carefully remove it form the hoist;
  3. Get an empty bucket, where to drain oil and some cloth to clean the hoist;
  4. Remove the oil plug, which is usually located in the middle of the cylinder;
  5. Lay the jack on the side and drain all oil out of the jack into the bucket, wipe spilled oil off the tool;
  6. Fill new oil inside the jack trough the oil opening till it starts to leak out of the drain hole. Make sure dirt doesn’t get into the hole in the filling process;
  7. Close the drain hole with an oil plug and close the release valve;
  8. Reinstall the jack back to the hoist;
  9. Bleed air out of the jack;
  10. Raise and lower the tool few times to see if everything works properly.

Here is a video showing the process of oil change on a hydraulic jack (oil change on bottle jack starts at 1:40).

Billy Miller
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