hydraulic jack issues

Doesn't the jack have an instruction manual?

Hydraulic jacks usually work by pumping a lever to move the fluid/buil up pressure and lift/move the vehicle. To lower the vehicle the pressure needs to be released, this is usually done by slackening a small knob or screw which allows the liquid to flow back into the reservoir.

'If all else fails read the instructions.'

(PS When jacking a car always use chocks and another means of support....don't get underneath if the operator doesn't know how to use the equipment!)

EIGHT ton?!?! Check to make sure hydraulic oil is topped off.

I suspect the medium knob is a bleed-off of some sort. Maybe best to keep it closed.

No offense intended but if he can't figure that jack out he better stay out from underneath the vehicle.

make, model?

Find somebody who knows how to work the hydraulic jack show you how to use it. If you cannot find someone, follow these steps:

1. Put the jack on a flat surface with no weight on it.

2. Turn the knob clockwise to shut off the fluid line.

3. Work the handle up and down to make the cylinder go up.

4. When the cylinder does not go up any further, stop working the handle.

5. Turn the knob counterclockwise to open the fluid line.

6. Press down on the cylinder with your hand to force it down.

7. Repeat steps 2 through 6 several times.

8. Put a weight such as a large can filled with rocks on the jack.

9. Follow steps 2 through 5 several times. The weight will force the cylinder down.

10. When you open the fluid line with a weight on the jack, turn the knob only a very small amount at first to keep the cylinder from coming down too fast.

11. Never put any part of your body under the weight when the weight is supported only with the jack.

Anyone with the inclination and the ability to remove an automobile engine to work on it should already know how to use a hydraulic jack, even if he has never seen one. I suspect the inquiry is not real.

In these days of safety first, there is possibly an interlock, a bit like a 'dead-man's handle' which require operating to get the thing down?? Maybe the unexplained knob is somethnig to do with this?

PS does the thing weigh 8 tons, or is that it's lifting capacity?!?