The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/

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Ignoramus16322 wrote:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/


Igor, you can rebuild yours (just needs a seal or O-ring or two) or you
can simply buy another one from HF. This time, I'd get an air/over/hydraulic
one like this one:

http://www.harborfreight.com/cpi/cta...emnumber=94562

I haven't seen a US manufactured 8 ton long throw jack in many years.

Grant

On Sun, 17 Aug 2008 18:35:00 -0500, with neither quill nor qualm,
Ignoramus16322 quickly quoth:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So learn some dexterity, Ig. gd&r Alternatively, you could use the
winch to lower the load instead of the hydraulics. g

Additionally, mill a large diameter lever or round knob/cap for the
valve stem and pop it on when you want to use the valve.


So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/

I've seen some nice air-overs but they're all 8-T and long bodied,
built for the shop cranes, not the truck cranes.

--
It is pretty hard to tell what does bring happiness;
poverty and wealth have both failed.
-- Kin Hubbard

On 2008-08-18, Grant Erwin wrote:
Ignoramus16322 wrote:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/


Igor, you can rebuild yours (just needs a seal or O-ring or two) or you
can simply buy another one from HF. This time, I'd get an air/over/hydraulic
one like this one:

http://www.harborfreight.com/cpi/cta...emnumber=94562

I haven't seen a US manufactured 8 ton long throw jack in many years.


Grant, I need a much smaller 3 ton one (12 inches retracted). Your
jack is for a 2 ton shop crane, whereas my issues are with the truck
crane. I will call HF for a rebuild kit or replacement. I think that
they have one. I definitely do not need air over hydraulic.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
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On 2008-08-18, Larry Jaques novalidaddress@di wrote:
On Sun, 17 Aug 2008 18:35:00 -0500, with neither quill nor qualm,
Ignoramus16322 quickly quoth:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So learn some dexterity, Ig. gd&r Alternatively, you could use the
winch to lower the load instead of the hydraulics. g

Additionally, mill a large diameter lever or round knob/cap for the
valve stem and pop it on when you want to use the valve.

Larry, I think that you are mostly right. The problem is that when the
boom is raised high, the wire rope hangs on the bottom lengthwise slot
in the boom, beneath the roller, instead of being suspended from that
roller.

I took the boom to my mill and lengthened the slot by an inch, which
will hopefully enable the winch to work even when the boom is fully
raised.

If so, then, I will be able to use the winch at those elevations.

Also, on the hydraulic front, I added a cross "T" handle to the
hydraulic handle. I practiced a little to close the valve by holding
the body of the handle, so that I would not overtighten it, and open
it by holding on to the T.

This does not solve the leaking issue, but it solves all other issues.

i

I had a similar problem with an 8 ton shop crane. I bought it from
Northern Tool (formerly known as Northern Hydraulics. They sold me a
Kit that didn't even come close to fitting. The piston was so sloppy
when I took it apart that I brought the jack back to them. They didn't
care. They offered to sell me a new, USA made jack, which I bought.
It has worked well for 3 or 4 years now. It is double acting!. Not
happy with Northern Tool for not standing behind the original jack, but
they told me that they no longer carry the Chinese model that failed.
Maybe they have on in the size you need.

Pete Stanaitis
-----------------------

Ignoramus16322 wrote:
The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/

Ignoramus16322 wrote:

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/


Wrong set of pictures.

Is there an oring under the nut surrounding pumping piston? If so, replace.

Wes

On Aug 17, 7:35*pm, Ignoramus16322 ignoramus16...@NOSPAM.
16322.invalid wrote:
The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

http://igor.chudov.com/projects/Harb...t-Truck-Crane/

You might try disassembling it to flush out any machining debris, and
filter the oil through a paper coffee filter. I've had better luck
reassembling hydraulics with Teflon paste rather than tape.

That round lump on the side that looks like a rivet is the rubber oil
filler plug.

A knurled 2" knob makes them easy to control. I press an aluminum disk
onto a 1/2" steel rod.drilled and slotted to fit over the existing
release. 2" is probably large enough to overtighten the needle valve
if you aren't careful.

Jim Wilkins

On Mon, 18 Aug 2008 01:15:07 GMT, with neither quill nor qualm, Grant
Erwin quickly quoth:

Ignoramus16322 wrote:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/


Igor, you can rebuild yours (just needs a seal or O-ring or two) or you
can simply buy another one from HF. This time, I'd get an air/over/hydraulic
one like this one:

I was going to suggest that, but it's on the back of his pickup.



http://www.harborfreight.com/cpi/cta...emnumber=94562

I haven't seen a US manufactured 8 ton long throw jack in many years.

Compare the length of that beastie with the (5" ram travel) jack in
the 37555 crane Ig has, Grant. g
http://www.harborfreight.com/manuals...7999/37555.PDF

--
It is pretty hard to tell what does bring happiness;
poverty and wealth have both failed.
-- Kin Hubbard

On Sun, 17 Aug 2008 21:45:39 -0500, with neither quill nor qualm,
Ignoramus16322 quickly quoth:

On 2008-08-18, Larry Jaques novalidaddress@di wrote:
On Sun, 17 Aug 2008 18:35:00 -0500, with neither quill nor qualm,
Ignoramus16322 quickly quoth:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So learn some dexterity, Ig. gd&r Alternatively, you could use the
winch to lower the load instead of the hydraulics. g

Additionally, mill a large diameter lever or round knob/cap for the
valve stem and pop it on when you want to use the valve.

Larry, I think that you are mostly right. The problem is that when the
boom is raised high, the wire rope hangs on the bottom lengthwise slot
in the boom, beneath the roller, instead of being suspended from that
roller.

_Notch_ that puppy.


I took the boom to my mill and lengthened the slot by an inch, which
will hopefully enable the winch to work even when the boom is fully
raised.

Oh, you did that already. Good.


If so, then, I will be able to use the winch at those elevations.

Alternatively, use the winch to take up all slack and raise the load
as far as possible, then use the hydraulics to finish raising it to
the necessary level.

Or cut of that roller bracket and weld the damned thing on the front
where it belonged in the first place. shrug


Also, on the hydraulic front, I added a cross "T" handle to the
hydraulic handle. I practiced a little to close the valve by holding
the body of the handle, so that I would not overtighten it, and open
it by holding on to the T.

Excellent idea.


This does not solve the leaking issue, but it solves all other issues.

Control is everything! Didn't your crane come with a valve kit? Pick
one up at HFT.

--
It is pretty hard to tell what does bring happiness;
poverty and wealth have both failed.
-- Kin Hubbard

"Larry Jaques" wrote in message
...
On Sun, 17 Aug 2008 18:35:00 -0500, with neither quill nor qualm,
Ignoramus16322 quickly quoth:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So learn some dexterity, Ig. gd&r Alternatively, you could use the
winch to lower the load instead of the hydraulics. g

Additionally, mill a large diameter lever or round knob/cap for the
valve stem and pop it on when you want to use the valve.


So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/

I've seen some nice air-overs but they're all 8-T and long bodied,
built for the shop cranes, not the truck cranes.

--
It is pretty hard to tell what does bring happiness;
poverty and wealth have both failed.
-- Kin Hubbard

If you go the repair route, once you get your leak fixed, restrict the oil
passage to limit the down speed...

Ignoramus16322 wrote:
The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.

So. I would like to buy a replacement jack, preferably something of
"high quality", chrome plated cylinders, made in USA or some such. Are
there any suppliers who sell similar but better jacks?

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/

overkill it
for a resonable price you can get a 20 ton in that size,
short throw or long.
HF has them, I need one to level a house.

Ignoramus16322 wrote:
On 2008-08-18, Larry Jaques novalidaddress@di wrote:
On Sun, 17 Aug 2008 18:35:00 -0500, with neither quill nor qualm,
Ignoramus16322 quickly quoth:

The hydraulic jack on my crane has two problems:

1) it leaks around the small (pumping) cylinder
2) When I open the valve, it opens too abruptly, so the crane drops
instead of going down slowly, I totally hate this.
So learn some dexterity, Ig. gd&r Alternatively, you could use the
winch to lower the load instead of the hydraulics. g

Additionally, mill a large diameter lever or round knob/cap for the
valve stem and pop it on when you want to use the valve.

Larry, I think that you are mostly right. The problem is that when the
boom is raised high, the wire rope hangs on the bottom lengthwise slot
in the boom, beneath the roller, instead of being suspended from that
roller.

I took the boom to my mill and lengthened the slot by an inch, which
will hopefully enable the winch to work even when the boom is fully
raised.

If so, then, I will be able to use the winch at those elevations.

Also, on the hydraulic front, I added a cross "T" handle to the
hydraulic handle. I practiced a little to close the valve by holding
the body of the handle, so that I would not overtighten it, and open
it by holding on to the T.

This does not solve the leaking issue, but it solves all other issues.

i

Every bottle jack & hydraulic engine hoist I have ever seen will leak if
stored with the valve closed, you might try to park it with the valve
cracked open 1/4 turn or so & see if the leak stops.

MikeB

Wes wrote:

Ignoramus16322 wrote:

Pictures are he

http://igor.chudov.com/projects/Harb...t-Truck-Crane/


Wrong set of pictures.

Is there an oring under the nut surrounding pumping piston? If so, replace.

Wes

Oops, didn't see the jack in the corner of lift.

Wes

If you can pump it up, but it drops down quickly, you may have air in
the system that can be purged out when you add more jack oil. Chinese
hydraulic actuated tools are notorious for developing leaks. If you
remove the jack from the crane, you should be able to put it on its
side and find and remove the “air bleed” plug. If you pump the jack
part way, you can more easily add jack oil in this hole. Cycle the
ram up and down, and make sure that you have a pan or rags to catch
any overflow. Jack oil can be obtained from your local auto parts
store. Maybe they’ll have this version: http://www.amazon.com/JACK-OIL-STOP-.../dp/B0002KKIBY
(Sometimes I’ll use automatic transmission fluid as a substitute.)

Lots of people are stuck with cheap floor jacks that they feel that
they should be able to repair, but just can’t find parts. I’ve taken
apart floor jacks and re-assembled them with o-rings or homemade seals
with middling success. If you disassemble yours, make sure that you
keep track of the parts and don’t loose the ball bearing or spring for
the check valve. I’ve spent hours hunting one down after it rolled
under the workbench.

It’s interesting to see how they’re assembled anyways. I found
pictures of someone rebuilding a floor jack he
http://www.garagejournal.com/forum/s...t=18055&page=4
This one shows what looks like cup seals and leather backing. The
seals that are on pumps vary, but this gives a general idea of what
you might expect if you start disassembly. Some real old-time jacks
used leather, rope or string packing that could be compressed with a
sleeve and gland nut similar to what was found on older gate valves or
water pumps:
http://www.diybob.com/diyPackingGland.htm
http://www.monarch-mclaren.com/leather.htm

I’ve still not figured out why most Chinese jacks fail. I’m not sure
of the materials used in their seals. (Nitrile (Buna-N) should be the
best choice.) Could be poor fit up and excessive clearances cause the
seals to extrude and fail prematurely. I’ve cleaned out machine chips
that caused the balls on the check valves to leak. Could be a bad
seat where the ball fits in the check valve. In that case, the pump
doesn’t hold its position under load. Bad pump design might pull the
piston out too much causing it to wobble and prematurely stretch and
wear the seal.

Some people have tried to make a go of supplying repair parts for
imports, but it doesn’t seem profitable: http://www.hyjacks.com/H32.HTM

Good primers on jacks: http://www.hyjacks.net/animation.htm ,
http://www.hyjacks.com/H7.HTM

Background on hydraulic jacks and repairable brands: http://www.hyjacks.com/H2.HTM
, http://www.jackxchange.com/

Hydraulic seal types:
http://www.sealing.com/hydraulic-seals/
Hydraulic seal materials and failure modes (industrial):
http://www.epm.com/faq.html

If I were to re-build another jack, I might get some hydraulic seals
or rod seals from McMaster Carr or machine a new pump with a packing
gland.

Different company from the one quoted above. (These guys claim to
sell parts that will fit the imports, but I haven’t used them, can’t
vouch for them, and it might be a pricey gamble for what you are
trying to fix):
http://www.hydjack.com/krk305.html

Lots of people say to save time and money by buying only good quality
products. They’re probably right, but I still like figuring out what
goes wrong and why.

On Aug 19, 10:47 pm, "Denis G." wrote:
.....
Some people have tried to make a go of supplying repair parts for
imports, but it doesn’t seem profitable:http://www.hyjacks.com/H32.HTM

I ordered standard metric cups that fit the cylinder bore and machined
adapter bushings to fit them to the piston. The piston and cylinder
were soft and easily machined to a good finish. You can also order
piston rod and cylinder stock from Bailey, http://www.baileynet.com/

Jim Wilkins

Ignoramus16322 wrote in
:

On 2008-08-18, Larry Jaques novalidaddress@di wrote:
On Sun, 17 Aug 2008 18:35:00 -0500, with neither quill nor
qualm, Ignoramus16322
quickly quoth:


snip


Larry, I think that you are mostly right. The problem is
that when the boom is raised high, the wire rope hangs on
the bottom lengthwise slot in the boom, beneath the roller,
instead of being suspended from that roller.

I took the boom to my mill and lengthened the slot by an
inch, which will hopefully enable the winch to work even
when the boom is fully raised.

If so, then, I will be able to use the winch at those
elevations.


snip

Iggy,

I just purchased the same Harbor Freight crane for our
Biology Department's pontoon boat, and ran into the same
problem with the cable rubbing on the slot's lower end at
high arm elevations. I can't figure out their concept in the
cable switch-back on the rollers...cable over the far side on
the top roller and the near side of the bottom. ??? It looks
like whoever designed it, never actually saw it in use. Or,
more likely, someone in manufacturing misread the print and
drilled the top hole in the wrong location...over and over,
and over again.

So, as opposed to your solution, I elongated the hole under
the top roller, in the direction of end of the arm, about
another 3/4". This allowed me to ran the cable on the far
side of both rollers. Now the length of the slot under the
bottom roller makes sense, and I can get full elevation
without interfering with the cable.

I have pictures, if this isn't clear.

Ken

On 2008-08-29, Ken Moffett wrote:
Larry, I think that you are mostly right. The problem is
that when the boom is raised high, the wire rope hangs on
the bottom lengthwise slot in the boom, beneath the roller,
instead of being suspended from that roller.

I took the boom to my mill and lengthened the slot by an
inch, which will hopefully enable the winch to work even
when the boom is fully raised.

If so, then, I will be able to use the winch at those
elevations.


snip

Iggy,

I just purchased the same Harbor Freight crane for our
Biology Department's pontoon boat, and ran into the same
problem with the cable rubbing on the slot's lower end at
high arm elevations. I can't figure out their concept in the
cable switch-back on the rollers...cable over the far side on
the top roller and the near side of the bottom. ??? It looks
like whoever designed it, never actually saw it in use. Or,
more likely, someone in manufacturing misread the print and
drilled the top hole in the wrong location...over and over,
and over again.

So, as opposed to your solution, I elongated the hole under
the top roller, in the direction of end of the arm, about
another 3/4". This allowed me to ran the cable on the far
side of both rollers. Now the length of the slot under the
bottom roller makes sense, and I can get full elevation
without interfering with the cable.

I have pictures, if this isn't clear.

Ken, it is clear. I also wondered about that design

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/