Grapple hyd. cylinder

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perry

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Aug 22, 2006
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Hey guys, picked up half of a two cylinder grapple, the arms are fine but the hyd, cylinder piston is bent slightly. I can unscrew the upper portion and remove the piston but, the manufacture name is unreadable. I need to know the best place to purchase a replacement piston, it has the round pin receiver on top of the piston.
 

jmatt20

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May 18, 2005
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are you talking about the piston or the rod that the piston is bolted to. i've seen bent rods but can't say i've seen a bent piston. if the piston is destroyed most likley the cylinder tube is also ruined, if the rod is bent too much it will ruin the cylinder head that it slides in and out of . any good hydraulic repair shop can make you a replacement for any of these components . the shop i use can make these parts for me for less than the bobcat dealer charges. another option is check northern tool or the surpluss center on line and see if they have a cylinder in stock that matches the one you need ie. stroke, bore ,and end fittings. a lot of people that manufacture after market attachments use "off the shelf" hydraulic components.
 

Tazza

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are you talking about the piston or the rod that the piston is bolted to. i've seen bent rods but can't say i've seen a bent piston. if the piston is destroyed most likley the cylinder tube is also ruined, if the rod is bent too much it will ruin the cylinder head that it slides in and out of . any good hydraulic repair shop can make you a replacement for any of these components . the shop i use can make these parts for me for less than the bobcat dealer charges. another option is check northern tool or the surpluss center on line and see if they have a cylinder in stock that matches the one you need ie. stroke, bore ,and end fittings. a lot of people that manufacture after market attachments use "off the shelf" hydraulic components.
Exactly, any machine shop can build a new piston and rod if thats the problem. Even if you know someone that is handy on a lathe they can build them too. Seals are cheap as are the materials. I agree that if you can find a new cylinder at a good price go for it, but i wouldn't pay hundreds for one.
 
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perry

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Exactly, any machine shop can build a new piston and rod if thats the problem. Even if you know someone that is handy on a lathe they can build them too. Seals are cheap as are the materials. I agree that if you can find a new cylinder at a good price go for it, but i wouldn't pay hundreds for one.
Thanks guys, I guess my terminology was off, I should have said 'piston rod'.
Do the grapple hydraulic cylinders have internal pressure relief valves?.
Perry
 

farmboy55

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Aug 16, 2006
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Thanks guys, I guess my terminology was off, I should have said 'piston rod'.
Do the grapple hydraulic cylinders have internal pressure relief valves?.
Perry
You can purchase the rod from Bailey's Hyd in Knoxville, Tn. I just order the blank rod in the size I need, then thread the piston end and cut the eye off the old one & weld it on the new rod. Just did 2 myself. dennis no releif valve inside of the cylinder
 

farmboy55

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You can purchase the rod from Bailey's Hyd in Knoxville, Tn. I just order the blank rod in the size I need, then thread the piston end and cut the eye off the old one & weld it on the new rod. Just did 2 myself. dennis no releif valve inside of the cylinder
PS Bailey has good deals on cylinders also.
 

sterlclan

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May 1, 2004
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Thanks guys, I guess my terminology was off, I should have said 'piston rod'.
Do the grapple hydraulic cylinders have internal pressure relief valves?.
Perry
as far as I know they are regular pistons the relief is in the machine..........Jeff
 

jerry

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as far as I know they are regular pistons the relief is in the machine..........Jeff
If the gland bore is distorted or oversize because of the bent rod you can bore it and bring it back to size with fiber wear rings. I did this with my tilt cylinder rather than make a new gland. Most heavy duty cylinders now use wear rings on the piston and in the rod bore. Otherwise nailsbeat is building grapples and probably has cylinders.
 

Tazza

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If the gland bore is distorted or oversize because of the bent rod you can bore it and bring it back to size with fiber wear rings. I did this with my tilt cylinder rather than make a new gland. Most heavy duty cylinders now use wear rings on the piston and in the rod bore. Otherwise nailsbeat is building grapples and probably has cylinders.
Thats a good point, slight wear still seems to be ok, but if its bad you really need to get it repaired.
If you don't have a lathe, any machine shop will me able to machine you a new rod. They are quite easy if you have a lathe that will allow you to cut threads (most do). They could even make a new glad nut if required, again these aren't that complicated, just takes a bit of time on the lathe.
 
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perry

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Thats a good point, slight wear still seems to be ok, but if its bad you really need to get it repaired.
If you don't have a lathe, any machine shop will me able to machine you a new rod. They are quite easy if you have a lathe that will allow you to cut threads (most do). They could even make a new glad nut if required, again these aren't that complicated, just takes a bit of time on the lathe.
I've got a 1946 southbend lathe that works great, but the threading attachment is labor intensive because it's all manual. A person needs to know what he's doing to get a good thread cut from this machine.
If I'm not mistaken?, shouldn't the piston rod be chrome plated?.
 

Tazza

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I've got a 1946 southbend lathe that works great, but the threading attachment is labor intensive because it's all manual. A person needs to know what he's doing to get a good thread cut from this machine.
If I'm not mistaken?, shouldn't the piston rod be chrome plated?.
Chrome or black nitride also works well.
You can buy the bar precision ground and chrome plated. Just clean any swarf out of the jaws of the chuck before you clamp the rod in!!!!! Been there done that... The chrome is very hard, but the metal under it is quite soft and dents easily, unless you go the induction hardened stuff.
 
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perry

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Chrome or black nitride also works well.
You can buy the bar precision ground and chrome plated. Just clean any swarf out of the jaws of the chuck before you clamp the rod in!!!!! Been there done that... The chrome is very hard, but the metal under it is quite soft and dents easily, unless you go the induction hardened stuff.
Bailey's quoted a 3000 psi replacement for $129.00. Seems reasonable to me?.
 
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perry

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Seems very reasonable to me!
When I said 'replacement' it was not an exact replacement. keep in mind I have half a grapple, leaving me the option to weld on gusset for the rear (bucket) mount point of the cylinder.
 

Tazza

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When I said 'replacement' it was not an exact replacement. keep in mind I have half a grapple, leaving me the option to weld on gusset for the rear (bucket) mount point of the cylinder.
Well over here you are looking at retail price of $40 of seals, 30-50 for steel then machining work. If you changed the style you can at least get another cylinder later.
 
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