Floor crane servicing question

[Highway_Glider]

Hi all.

I want to ask the hive mind about my engine hoist.

It's a Blackjack 2 tons unit with a foot pump.

Don't have a book for it and cannot find actual info for it. I always endup on bottle jacks....



It will still raise itself but will not under load. So not very usefull right now.



I need to bleed or replennish the fluid. I think replacing is better than just refilling but you tell me.

I think #1 is a preset checkvalve.

#2 is bleeding???

#3 easier refill than using #2????? Drainning????

What about the big square nut on the back end?



So anyway I need to know what to unscrew without getting a spring flung in my face or lost, sercice how and with what then bleed the darn thing.

The cylinder is higher than the pump so I raise the pump and turn the cylinder upside down??


Gotta run but I will check back in later.

Thanks for all input.

[chuck hahn]

I would be making an guess, but i would think that if the oil is at least to the top of #2 the jack would be sufficiently full enough to operate correctly.