adding fluid to hydraulic floor jack

Old 12-09-12, 12:47 PM
sgull's Avatar
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adding fluid to hydraulic floor jack

I've been using a particular 2-ton hydraulic floor jack for years and have never bothered checking the hydraulic fluid until now because it seems like it's not jacking as well as it used to. I was looking online for some instructions on the procedure to check/add fluid to the jack, and came across the description of where the filler plug is and to "begin adding hydraulic fluid into the reservoir until the fluid level is approximately 3/16" from just covering the inner-cylinder as viewed from the oil filler plug hole". Well, when I look into the oil filler plug hole, I can see top of the inner cylinder mentioned, but that's all I can see. I can't see around the side edges of the cylinder to see the level of the fluid inside. So if I decide to add fluid, how do really know when the fluid level is approximately 3/16" from "just covering" the inner cylinder? The instructions mention it's very important not to underfill or overfill. Any comments/advice appreciated, thanks.
Old 12-09-12, 12:50 PM
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Normally if it's low on oil it will not reach full height. If it's jacking slower, more likely worn seals in the pump. If you think it's low, what I would do is add a couple of ounces and then try jacking to see if it goes to full height.
Old 12-09-12, 12:52 PM
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Don't know if it's correct or not but the few times I had to top off my 2.25 ton floor jack I filled it until the cylinder was covered. My jack did blow a seal last time I tried to use it..... but it is about 30 yrs old
Old 12-09-12, 01:56 PM
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Mine seems like it reaches full height okay, but seems like when jacking up at two thirds or so of full height it jacks slower than it used to. I went ahead and added maybe an ounce and a half of fluid but still could not really definitely see or be able to tell for sure how far down the fluid level is from the top of the inner cylinder. The instructions I came across warn "If too little or too much fluid is added, the jack will experience a wide-range of performance issues." I haven't particularly noticed any leakage or seepage of fluid out of the jack, although over time I suppose slight seepage could have been occurring but slight enough to remain un-noticed. Since adding a little fluid as I mentioned, so far it seems to be working better, but haven't used it enough yet to be sure. Generally the jack seems to work fine but just getting and knowing for sure if the fluid level correct or close enough to being correct I guess would help me sleep at night.
Old 12-10-12, 05:47 AM
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Could you have any air or water in your fluid?
Did you check the color of the fluid before filling?
3/4 to full hight is when you put the most stress on the fluid.
I drained my floor jack this summer (removed fill plug, sat jack upside down). My fluid had a bit of a milky color to it which would be from leaving it in the cold (dirt floor) garage we have at this house.

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