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shop press cylinder replacement

carmantl

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Joined
Dec 19, 2015
Messages
237
Our faithful 25 year old 40 ton shop press has a bad cylinder with no replacement parts available. It operated in an inverse position powered by an electric hydraulic pump. We can fab brackets to use another brand cylinder but the least expensive one I can find is over $600. Does anyone know of a way to use a conventional 40 ton hydraulic jack to replace the cylinder? We've been told that conventional jacks will not work inverted?
 
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nadogail

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Joined
Jan 23, 2009
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31,910
Location
Coronado, CA
Our faithful 25 year old 40 ton shop press has a bad cylinder with no replacement parts available. It operated in an inverse position powered by an electric hydraulic pump. We can fab brackets to use another brand cylinder but the least expensive one I can find is over $600. Does anyone know of a way to use a conventional 40 ton hydraulic jack to replace the cylinder? We've been told that conventional jacks will not work inverted?
Visit Harbor Freight and see how they use a conventional jack to press up against the press frame to make the platen go down.
 

F-22

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Joined
Jan 23, 2022
Messages
1,830
I'm sure there's markings on the seals. I doubt it's actually worn out. Usually there's absolutely no reason to make one-off custom seals, so they must be standard.

The piston rod is easy to make if you have access to a lathe. A hard chromed and precision centerless ground shaft can be bought by the meter (very cheap) in all standard dimensions... Typically just cut to length and drill and tap a threaded hole on both ends, or maybe mill out an "eye" on one end.
 
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carmantl

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Dec 19, 2015
Messages
237
Thanks for the replies but the issue is the male cylinder ram is pitted. The best hydraulic cylinder shop in town couldn't fix it.
 

whateg01

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Joined
Mar 13, 2006
Messages
11,211
Location
doo dah, kansas, usa
Thanks for the replies but the issue is the male cylinder ram is pitted. The best hydraulic cylinder shop in town couldn't fix it.
Can't tell where you are located, but your best hydraulic shop probably can fix it but they don't want to. Not enough profit in a simple job. Even if the rod is pitted, it should still build pressure because the u-cup or whatever it uses is what seals.
 

crane operator

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Joined
Jul 1, 2016
Messages
307
Location
sw missouri
You still have the hydraulic pump, so all you need is the cylinder. Lets have a diameter (rod and barrel) and length of the cylinder, and I'm sure we can come up with something for less than $600. How about a picture of the press also.

Be nice to know the distance between the rails at the top- so you don't end up with too fat of a cylinder barrel to fit in between.

Any kind of a enerpac or knock off one way cylinder should work. It would be easier than retrofitting a bottle jack and much nicer to use.


 

bigfunwmu

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Joined
Oct 26, 2013
Messages
406
Location
S. MN
Many hydraulic shops don't do small cylinders anymore, so many cheap "import" cylinders around that telling somebody you can fix a cylinder for $500 when they can buy a replacement for $300 just makes them mad. So many shops more "diplomatic" option is to say they can't fix it when they really mean they can't fix it at a price that won't piss you off. Lots of options out there for generic-ish cylinders, like the other said post your specs... Rod, bore, stroke length and pressure rating. Don't want a 2500 PSI farm cylinder on a 10,000 PSI jack rated power unit, don't want a micro 10,000 PSI jack cylinder on a 3000 PSI gear pump power pack either.
 
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