Hi All, I have a problem with an old hydraulic jack I found by the side of the road. Just a few weeks ago I borrowed a friends jack just like this, and I almost went out and bought a new one! One man's trash is another man's treasure... Anyways, its a very common Taiwan 2 ton floor jack that is about 20 years old. It pumps just fine until it gets near its maximum extension and then it starts to peter out. You can feel a change in the pumping resistance, in that it only has a slight resistance, right near the bottom of the stroke. I can get it to work correctly if I open up the filler plug on the hydraulic ram. When I open the plug I can hear air escape. I suspect that this extra air pressure in the reservoir is causing some sort of "air lock" in the pump... I have tried to bleed the air out several times by pumping/releasing it, but it will only work correctly with the filler plug loose. I also drained and filled the fluid, to the top of the filler plug, when the ram was fully retracted. I also took apart and examined for obvious problems: the pumping piston, over-pressure valve, and the release valve, still no joy. What gives, this should be simple, but I haven't figured it out yet! Any help is appreciated. Thanks, Tim
| 
