Harbor Freight 20T press won't press

[Obi-Wan]

I have a Harbor Freight 20-ton hydraulic press that I bought used. It seems that the press arbor should have about 5.5" of travel, total, right?

My press seems to exert plenty of force for the first 2", but after it hits a certain point, it just suddenly stops pushing. After that, I can pump all night, and it won't exert any additional force or cause any movement. If there's no resistance, then it'll travel the entire 5.5". It's full of fluid.

Any idea what might be wrong with it? More importantly, any idea how to fix it? 2" of travel is an almost useless amount for a press.

 

[Grokew]

Please mind that I have almost no knowledge. Does it have sufficient hydraulic fluid/oil in it? Is it free from air bubbles?

 

[darkzero]

Sounds like it needs to be bled and/or needs oil. I have no experience with these but it's just a bottle jack.

If there's no obvious sign of oil leaks, try bleeding first. The way I bleed my bottle jack is open the release valve, then pump it like 5-10 times. Wait a bit for any air bubbles to settle if there were any, close the valve, then try to pump to fully extend. If it still doesn't then check if it needs oil.

 

[finn]

Low on hydraulic fluid. If there’s no fluid to pump, the ram won’t move any farther.

Refill and bleed the air.

 

[Obi-Wan]

As I said in my initial post, it's not low on fluid. I've checked that several times, and it's full. I'll try bleeding it, though.

 

[sz0k30]

HF 20 ton hydraulic jacks are pretty inexpensive, buy another one.

 

[Jswain]

Seals likely split. Rebuild or replace bottle jack. Probably easier to replace

 

[alfadan]

I wouldn't be surprised if the cylinder has a bunch of chips and **** in it and its screwing up the pump. I think its fairly common on these older HF bottle jacks.
Mine has been acting up lately where it just randomly doesn't build pressure.

 

[steel 35]

Good time to switch to the air operated Jack!
I like mine a lot.

 

[redmondjp]

+1 on the above, buy a new bottle jack, and check fluid level on it as sometimes their new stuff doesn't come with enough oil inside of it.

 

[Obi-Wan]

Well, I bled the jack today. I then topped off the fluid again to replace the space formerly taken by air bubbles, but I don't think I added much at all. When I tested the press, I was able to crush a 2x4 at the full extension of the arbor. It never would have done that before, so I think it's in better shape now. Thanks for your recommendations.

 

[Vwpower]

I have the hf 20 ton and I have to push and hold the jack handle all the way to the right side when pumping to get it to pump.