Should a jack or hoist hold pressure?

[Mastiff]

My Harbor Freight engine hoist will slowly drop its arm to the ground over a day or so. Is this normal? I was using it to hold up my 14bff while I painted it, and it would have been nice to keep it suspended while the paint fully dried. I set it up a few inches over jack stands and when I came out in the morning it was down.

 

[Kain]

time to rebuild the pump or get a new pump bad juju there

 

[xenomarine]

my crappy jack does that. it's not good. all i do is get the piece in question to the desired height then put jackstands under it. my grandfather's old engine hoist held a 6.2 diesel for over a week without dropping, so i know that thing's still good.

 

[owenst7]

Icemans falling-apart cherry picker held a 6.2 in my side yard for several months lol. Didn't lose any pressure at all. If its annoying enough, rebuilding the ram is cheap and easy, although you can buy new ones at HF for pretty cheap. I've been eyeing an air over hydro for my cherry picker for a while. They're only like $80.

 

[TheBeast_88K5]

Rebuild the valve areas....

I've owned a HF floor jack (the big grey one) for 3 years, now.
The first week, I rebuilt the entire Hydraulic system.
I.e., pistons, seals, valves, snap rings, refilled with quality Hydraulic fluid.

It's worked flawlessly ever since.
Cost me about $8, and an hour.

Turned my $60 jack, into a quality jack....

Food for thought.

 

[dremu]

Rebuild the valve areas....

I've owned a HF floor jack (the big grey one) for 3 years, now.
The first week, I rebuilt the entire Hydraulic system.
I.e., pistons, seals, valves, snap rings, refilled with quality Hydraulic fluid.

It's worked flawlessly ever since.
Cost me about $8, and an hour.

Turned my $60 jack, into a quality jack....

Food for thought.

Replacing O-rings and snap rings is easy enough, those can be sourced locally ... where'd you get the seals or whatever else?

-- A

 

[TheBeast_88K5]

I meant O-rings when I said Seals.
The factory O-rings are in fact rubber, and deteriorate over time.

And, as for the pistons, mine had little hydraulic ports drilled into them.
All I did, was lightly hammered in an Airbrush Nozzle for a Paasche VL.
It decreases the amount of time it takes to raise the jack.

Less input, more output.

 

[Fordum]

It can be fixed. Either with seal/O-ring replacement, or a new ram. A quick temp fix is to drain out as much fluid as you can and replace it with motor oil.
20W-50 works good.

In a powered hydraulic system, the antifoam agents and the thinness in hydraulic fluid are needed. But in a simple system like that, most any non-corrosive liquid will work.
And the thicker, the slower it leaks down.

I used 90 weight once to get a jack working long enough to change a tire in the woods.
Come to think of it, I kept using that jack for a few years before I gave it away. Don't know how long they used it...........

 

[4X4HIGH]

Just for the record, hydraulic cylinders of any type are not meant to continually hold pressure for long periods of time (yes they might hold but it's not suggested to do so). You may have a faulty cylinder for sure if it dropped overnight but like I said, they aren't meant to be used as such anyways.