I got an old hydraulic jack. It is 10" high, 4.5" diameter, with a 2"
piston. It is obvious that it has sat for a long time. It had some mud on
the outside. Jack oil runs out the fill plug, and when I remove the turn
screw, jack oil comes out the bottom. The pump pumps out the piston, but
only a short way, then the pump becomes easy, leading me to believe it is
low on oil. BTW, how much oil do I put in there? Up to the fill hole?

Should I just put some jack oil in there, or is there a process to flush,
which may take out any water in there? Would some Marvel Mystery Oil harm
the seals? Would there be another fluid to flush it with? Or should I just
fill it with oil and call it good?

This appears to be an older one, not Chinese. Are these rebuildable? Out
scrounging for cribbing for a new container, and found a volume tank for a
compressor, too. Think I'll make a portable air tank out of that.

I love to go scrounging. Took my 86 yr. FIL, and he's just a big kid when
it comes to puttering and scrounging.

Steve

SteveB wrote:

I got an old hydraulic jack. It is 10" high, 4.5" diameter, with a 2"
piston. It is obvious that it has sat for a long time. It had some mud on
the outside. Jack oil runs out the fill plug, and when I remove the turn
screw, jack oil comes out the bottom. The pump pumps out the piston, but
only a short way, then the pump becomes easy, leading me to believe it is
low on oil. BTW, how much oil do I put in there? Up to the fill hole?

Should I just put some jack oil in there, or is there a process to flush,
which may take out any water in there? Would some Marvel Mystery Oil harm
the seals? Would there be another fluid to flush it with? Or should I just
fill it with oil and call it good?

This appears to be an older one, not Chinese. Are these rebuildable? Out
scrounging for cribbing for a new container, and found a volume tank for a
compressor, too. Think I'll make a portable air tank out of that.

I love to go scrounging. Took my 86 yr. FIL, and he's just a big kid when
it comes to puttering and scrounging.

Steve

Low on oil most likely. Take it apart, clean in suitable solvent, then
reassemble and fill with fresh jack oil. Any hydraulic shop should be
able to find suitable seals if needed.

"SteveB" wrote in message I got an old hydraulic jack.
It is 10" high, 4.5" diameter, with a 2"
piston. It is obvious that it has sat for a long time.
It had some mud on
the outside. Jack oil runs out the fill plug, and when I
remove the turn
screw, jack oil comes out the bottom. The pump pumps out
the piston, but
only a short way, then the pump becomes easy, leading me
to believe it is
low on oil. BTW, how much oil do I put in there? Up to
the fill hole?

Should I just put some jack oil in there, or is there a
process to flush,
which may take out any water in there? Would some Marvel
Mystery Oil harm
the seals? Would there be another fluid to flush it with?
Or should I just
fill it with oil and call it good?

This appears to be an older one, not Chinese. Are these
rebuildable? Out
scrounging for cribbing for a new container, and found a
volume tank for a
compressor, too. Think I'll make a portable air tank out
of that.

I love to go scrounging. Took my 86 yr. FIL, and he's
just a big kid when
it comes to puttering and scrounging.

Steve



Here's something to try before you do anything else. Pump it
to the point
where it stops then try pulling up on the ram as you pump
and see if it
begins to work again. There may be one area in the cylinder
where the
piston bypasses oil. That area may be corroded or else the
jack has been
overloaded and the cylinder is bulged at that point.
phil

On Wed, 9 Sep 2009 11:37:17 -0600, "SteveB"
wrote:

I got an old hydraulic jack. It is 10" high, 4.5" diameter, with a 2"
piston. It is obvious that it has sat for a long time. It had some mud on
the outside. Jack oil runs out the fill plug, and when I remove the turn
screw, jack oil comes out the bottom. The pump pumps out the piston, but
only a short way, then the pump becomes easy, leading me to believe it is
low on oil. BTW, how much oil do I put in there? Up to the fill hole?

Usually up to the bottom of the fill hole when the jack is standing
vertically and the ram is fully retracted.

And you shouldn't be removing the lowering valve all the way, and it
shouldn't leak from there - might need to change that seal too.

Should I just put some jack oil in there, or is there a process to flush,
which may take out any water in there? Would some Marvel Mystery Oil harm
the seals? Would there be another fluid to flush it with? Or should I just
fill it with oil and call it good?

Try regular jack oil first, and it might take a cycle or three to
purge any air from the ram. No solvents unless you totally
disassemble and flush it - the volatiles stay behind and can attack
seals, or otherwise affect long term reliability.

This appears to be an older one, not Chinese. Are these rebuildable?

Sometimes - Tear it down and make sure the bones are solid (if the
chrome plating on the ram is messed up repairs will cost more than the
jack is worth) and you can get all the seals and gaskets you need
first. No sense wasting effort if it's hopeless at the outset.

-- Bruce --