Need advice on servicing floor jack

[AVR2]

I've had my trusty 3-ton floor jack for about 10 years and never changed the oil. I bought it when I lived in Dubai; it wasn't a name brand, and I've long since lost the oil change instructions that came with it.

It's the kind of jack where, when you turn the handle, you turn two sprockets against each other to open or close the valve. The photos show the lower sprocket removed.

I'm guessing that the oil drain/fill plug is the large Allen-headed thing to the left of the valve control? I'm assuming that simply because it's accessible without needing to remove the lower sprocket. I don't actually have a large enough Allen socket, but I do have a 24mm deep socket, so I took the valve control out instead. I'm not sure what I'm looking at, but there's clearly plenty of oil still in the jack, and I had to replace the copper washer inside the bore.

Changing the oil should just be a case of taking out that Allen plug and then draining/refilling?

 

[bcschief]

There should be a rubber fill plug on the outer body of the cylinder usually on the top side.

 

[paulsomlo]

Changing the oil should just be a case of taking out that Allen plug and then draining/refilling?

Probably not - the Allen plug is probably access to either the overload or the working valve. As bcschief said, look for a rubber plug on the top side of the cylinder. Jack manufacturers in general, didn't make it easy to change oil - you'll need to pull that rubber plug and turn the jack upside down; that's why so few people change the oil in their jacks.