# Hydraulic Bottle Jack Issue



## YYCHM (May 13, 2021)

I have this 4 ton bottle jack that I keep in our travel trailer for changing tires.  I've used it maybe two times in the last 15-20 years.  Recently I needed to use it and discovered it's not functioning at all.  Thinking it needed a oil top up I added some jack oil but still nothing.  You can pump it all you want and it won't prime and jack.  Is there a trick to these things to get them going?  Seems pretty simple.  Close valve to jack, open valve to release.


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## DPittman (May 13, 2021)

Could be air, could be bad seals, etc. While I hate to be one to encourage throw away, you can buy those things so cheap on sale that it may not be worth your effort to repair?


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## YYCHM (May 13, 2021)

DPittman said:


> Could be air, could be bad seals, etc. While I hate to be one to encourage throw away, you can buy those things so cheap on sale that it may not be worth your effort to repair?



Ya, but is a new one just going to do the same thing in 10 years with no use?  It's not as if one uses this kind of thing on a regular basis and when you need it you need it.

No trick to jump start it eh?


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## DPittman (May 13, 2021)

YYCHM said:


> Ya, but is a new one just going to do the same thing in 10 years with no use?  It's not as if one uses this like kind of thing on a regular basis and when you need it you need it.
> 
> No trick to jump start it eh?


Is there an air bleed screw on it somewhere?  
Maybe try pulling the shaft up and see if that sucks in oil and displaces air?


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## kevin.decelles (May 13, 2021)

I have a couple that are prone to leaking, but Princess auto has deals so often they are almost disposable.  Garage sale/auctions -- also lots coming/going.  I'll give you a dollar for it.    Usable metal in there.


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## YYCHM (May 13, 2021)

DPittman said:


> Is there an air bleed screw on it somewhere?
> Maybe try pulling the shaft up and see if that sucks in oil and displaces air?



Nope, no bleed screw just the little T screw you use to close/release and a rubber plug that I assume is where you add oil.  Can't pull the ram/shaft up but it does unscrew?  What's the unscrewing about?

 The odd thing is that there is no evidence in the trailer that anything leaked out?


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## YYCHM (May 13, 2021)

kevin.decelles said:


> I have a couple that are prone to leaking, but Princess auto has deals so often they are almost disposable.  Garage sale/auctions -- also lots coming/going.  I'll give you a dollar for it.    Usable metal in there.



Ya BUT if you can't trust them to be usable when you need them  That's a dilemma now.


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## Chicken lights (May 13, 2021)

YYCHM said:


> Nope, no bleed screw just the little T screw you use to close/release and a rubber plug that I assume is where you add oil.  Can't pull the ram/shaft up but it does unscrew?  What's the unscrewing about?
> 
> The odd thing is that there is no evidence in the trailer that anything leaked out?


You unscrew it if you need more height 

Alternatively put a block of wood underneath it


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## YYCHM (May 13, 2021)

Looks like this trailer is 5400 lbs fully loaded with propane and water and can carry 1700 lbs of cargo, so about 3.5 T.

Would a 2 T scissor jack suffice for tire changes?


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## Chicken lights (May 13, 2021)

YYCHM said:


> Looks like this trailer is 5400 lbs fully loaded with propane and water and can carry 1700 lbs of cargo, so about 3.5 T.
> 
> Would a 2 T scissor jack suffice for tire changes?


All you need is a couple blocks of wood and a shovel. Drive the crappy tire onto a 4x4. Place a couple blocks under the axle then pull the trailer forward, so the axle sits on the blocks and now the tires in midair

If the inflated tire is too high to go on, dig a hole 

Farmboy style


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## DPittman (May 13, 2021)

YYCHM said:


> Looks like this trailer is 5400 lbs fully loaded with propane and water and can carry 1700 lbs of cargo, so about 3.5 T.
> 
> Would a 2 T scissor jack suffice for tire changes?


Scissor jacks are a bit of a pain but they are cheap and reliable.  I wouldn't think you'd ever be lifting half the entire weight of your trailer with a tire change so a 2t jack should work.


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## YYCHM (May 13, 2021)

Got the ram extended....






And collapsed and extended it a dozen times.  No change, won't pump up or hold.  Grrrrrrr.


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## Dabbler (May 13, 2021)

The seals are gone.  they can be rebuilt, but not worth the trouble for 30 bucks.


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## Tom Kitta (May 13, 2021)

I have lots of jacks including some that have some rust on the shaft. Usually seals do not just go away 100%. I would not be surprised if you did not have enough oil in them of type 32. Add oil till it flows out. Try again. The mechanism is so simple I also fail to see how it could... fail.

On the other hand the only reason to play around with one is for fun - they can be had for like 15 on auctions or less - maybe 10. New on sale are like 30 or maybe even less. 

Also it is princess auto brand - just go to PA and get a new one for free - they have 100% satisfaction guarantee with no expiry. You get the lowest price it sold for in the last 6 months. Or if discontinued the lowest price it had at its product end.


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## Dabbler (May 13, 2021)

I just wait until the one I want goes on sale at PA and buy it.  I ususally spend 9 or 19 dollars.


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## 6.5 Fan (May 13, 2021)

PA is good about replacing tools, pressure systems 1 year only. I had a Bur-cam pressure system 1.5 years old and they said go to Bur-cam for parts, no warranty past 1 year.


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## combustable herbage (May 13, 2021)

Sell it to Kevin and cut your losses


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## YYCHM (May 13, 2021)

Ok, I got it going again....  It's pumping up and holding

I think initially it needed oil and to have the air bled out of it.  Then in my frustration, I over filled it and the air had no place to go.  When It was starting to pump up I attempted to break the seal on the oil fill plug to see if air would escape and it shot out across the room along with a hefty stream of jack oil spraying me and the adjacent wall LOL. Good thing I wear glasses.  I'm going to pump it up and see if it holds overnight.  If it does, then I'll relegate it back to trailer duty and make it a pre-trip check item like I do with the trailer tires air pressure, propane, water etc etc.

Oh ya.... and I'll keep some jack oil in the trailer.


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## terry_g (May 13, 2021)

Do the pins on the pump linkage come out? if so pull the pump plunger and barrel and see if the 
seals have deteriorated. There should be a V-seal on the end of the pump plunger and probably 
a seal in the top of the plunger bore. There is also a check valve between the pump and the cylinder.
Most likely a ball and spring it may be stuck open.


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## John Conroy (May 14, 2021)

Make sure to store it standing up so air will not enter the pump chamber


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## YYCHM (May 14, 2021)

Just to close off this thread, the jack held pressure overnight so back into the trailer she goes along with a bottle of jack oil.

What I learned......

1. Don't over fill
2. To bleed air:  

Close valve and extend ram fully by hand, then open valve and collapse ram fully 10-30 times.  Once pumping repeat only pumping up rather than extending by hand.

3.  Check that jack is functional when checking other pre-trip items.






The one time I've needed to use that jack so far


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## Dabbler (May 14, 2021)

That one of those new high-tech air cooled tires?


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## John Conroy (May 14, 2021)

For my RV trailer I just use the same scissor jack that came with my truck. Only had to use it once since we bought the trailer in 2004.


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## historicalarms (May 14, 2021)

I don't think air-lock was your problem Craig, probably not low oil neither as you state no evidence of oil spill in the trailer...oil spill evidence just doesn't disappear...ever.
     Those bottle jacks are a 'single acting" hyd ram only,  there may have been a bit of air trapped in the bottom of the ram but it wouldn't interfere with operation at all, actually if all the valves in the jack were working correctly it should, although very slowly, still extend the ram. Air in a double acting hyd cylinder will cause "chattering" in it's operation until the air bleed itself from the ram thru a # of extensions/retractions.
      I believe the check/ball valve in your jack just became gummed up over time & wouldn't close when it was supposed too. There are 3 valves in a bottle jack, the treaded 'relief valve" we operate from the outside, a ball check valve that works itself and the "free flow" valve that is opened when you operate the hand lever to full out position.
        The free flow valve opening is simply an opening to allow oil to flow from its reservoir into the contained hyd pressure system. when you start the downward stroke of the handle it closes this valve and holds the stroke pressure within the system. There is an internal ball check valve between the handle stroke piston & the ram bottom that allows oil from the piston stroke to move one way only providing the treaded needle valve is closed, if this valve is open the oil simply returns to the oil reservoir without building pressure to extend the ram. 
     You will notice that when lifting something with a bottle jack that if the weight is much lighter than the jacks operating limit, the stroke is very easy but if your lifting very close to the limit, the stroke becomes very much harder, this is because with more weight pressure on the jack ram requires much more stroke pressure to open that check valve. 
     That is how the inexpensive "light duty" bottle jacks work but I have a 40 toner sitting in my shop that we used to lift D7 sized cats with to do the grouser bar welding i mentioned in another thread. That jack doesnt have a piston stroke to operate it, it has a rotary valve similar to a "Rotax engine" that will lift that 40 tons almost effortlessly...very slowly tho, maybe 10-15 thou lift on the ram to each stroke....that damn jack itself weighs probably 80 lbs.


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