Hydraulic Cylinder Replacement
- Thread starter BenTh
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Ok, and here is a closeup of the crossarm on the lift arms. You can see the seating flats where the pivot arm seated against it.
Given that I was going to have a failure, I'm happy that the cylinder is the thing that gave out rather than bending this arm, the pivot arm more than it did, or even the pivot rod for the pivot arm.
I'll be calling PT tommorow to see about replacing the cyclinder. I may get some rebuild kits for the other cylinders as JJ talked about. Given that this is an old machine, it might be a worthwhile winter task to rebuild the other cylinders.
Thanks for everyone's help with this. I'll let you know how it goes with getting a replacement etc.
thanks,
Ben
Given that I was going to have a failure, I'm happy that the cylinder is the thing that gave out rather than bending this arm, the pivot arm more than it did, or even the pivot rod for the pivot arm.
I'll be calling PT tommorow to see about replacing the cyclinder. I may get some rebuild kits for the other cylinders as JJ talked about. Given that this is an old machine, it might be a worthwhile winter task to rebuild the other cylinders.
Thanks for everyone's help with this. I'll let you know how it goes with getting a replacement etc.
thanks,
Ben
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J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
How about the piston and nut, what shape were they in. If the walls of the cylinder are even slightly out of round, there will be some leakage. If you have to buy all the guts for the cyl, it will probably be to your advantage to replace the complete cylinder. You could have someone mic the cylinder walls for out of roundness. In rebuilding the cylinder, the o-rings are simple, but the wiper on the upper part of the cylinder has to go in a certain direction.
My recommendation would be to buy one complete cylinder for the tilt, , and two kits for the other cylinders, just to have around if the lift cylinders ever start to leak. If it ain't broke, don't fix it.
My recommendation would be to buy one complete cylinder for the tilt, , and two kits for the other cylinders, just to have around if the lift cylinders ever start to leak. If it ain't broke, don't fix it.
J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
If you choose to rebuild, that nut on the bottom of the piston should have lock-nut fluid applied to the threads, but not to much as to contaminate the hyd fluid.
davesisk
Platinum Member
Thanks for the pics. If the rod end bent with the piston on it (which is what I'd presume) then it's probably pretty likely that the inside of the cylinder is also damaged, so the best advice is probably just to replace it. Call Power-trac for replacement cost, but definitely check with Gregory Poole Equipment's hydraulic shop as well...they may be able to get the same thing at a better price...maybe not, but worth a phone call.
I seriously doubt you need to worry too much about the slight bend in the pivot arm. If it were worse, you might need to straighten it, but I'd say it probably won't cause any issues with the slight amount of bend that it appears to have from the pics.
Good luck,
Dave
I seriously doubt you need to worry too much about the slight bend in the pivot arm. If it were worse, you might need to straighten it, but I'd say it probably won't cause any issues with the slight amount of bend that it appears to have from the pics.
Good luck,
Dave
Thanks for the tips JJ. A question from someone who's only had the piston rod out of the cylinder because it failed: how do these cylinders come apart?
I haven't tried anything yet, but from looking at it, I would assume that the end piece is threaded into the cylinder. Unscrewing that would free the piston (and rod assembly, if it were still attached!) Is that correct?
Do you need to take any special measures to get the end cap off? Like heating it? If it unscrews, I would probably just put it in a vise with pipe jaws and use a pipe wrench on the end. Of course, that may not be so good if it is soft metal and the cap is locked on???
I figured I'd get the rebuild kits as you mentioned and put them on the shelf for a winter project. Given the age of the machine (15 years), it's probably a good idea to go ahead and rebuild them and try to prevent potential disasters like the present one from happening. Currently I'm feeling lucky that the cylinder failure didn't damage anything else too severely.
Thanks,
Ben
I haven't tried anything yet, but from looking at it, I would assume that the end piece is threaded into the cylinder. Unscrewing that would free the piston (and rod assembly, if it were still attached!) Is that correct?
Do you need to take any special measures to get the end cap off? Like heating it? If it unscrews, I would probably just put it in a vise with pipe jaws and use a pipe wrench on the end. Of course, that may not be so good if it is soft metal and the cap is locked on???
I figured I'd get the rebuild kits as you mentioned and put them on the shelf for a winter project. Given the age of the machine (15 years), it's probably a good idea to go ahead and rebuild them and try to prevent potential disasters like the present one from happening. Currently I'm feeling lucky that the cylinder failure didn't damage anything else too severely.
Thanks,
Ben
</font><font color="blue" class="small">( If the rod end bent with the piston on it (which is what I'd presume) then it's probably pretty likely that the inside of the cylinder is also damaged )</font>
Hi Dave,
Actually, it's probably worse than that. I believe that the rod end came off the piston first, which is what caused the rod to hyperextend (I think that's only way that the rod could hyperextend???) Anyway the piston appears to be pushed back a little in the cylinder and is currently jammed. So I think the end of the rod came out of the piston, then started pushing it back when pressure was applied (with hydraulic fluid leaking around the hole in the piston.) Then the rod slipped to the side with the threaded end against the cylinder wall and bent. So there is probably the impression of the threads in the cylinder wall at minimum.
So, yeah, I'm just going to replace it. I couldn't fix the thing without another rod anyway (which doesn't come in a rebuild kit, I'm sure.)
Hi Dave,
Actually, it's probably worse than that. I believe that the rod end came off the piston first, which is what caused the rod to hyperextend (I think that's only way that the rod could hyperextend???) Anyway the piston appears to be pushed back a little in the cylinder and is currently jammed. So I think the end of the rod came out of the piston, then started pushing it back when pressure was applied (with hydraulic fluid leaking around the hole in the piston.) Then the rod slipped to the side with the threaded end against the cylinder wall and bent. So there is probably the impression of the threads in the cylinder wall at minimum.
So, yeah, I'm just going to replace it. I couldn't fix the thing without another rod anyway (which doesn't come in a rebuild kit, I'm sure.)
Sedgewood
Platinum Member
<font color="red"> I haven't tried anything yet, but from looking at it, I would assume that the end piece is threaded into the cylinder. Unscrewing that would free the piston (and rod assembly, if it were still attached!) Is that correct? </font>
Correct. Then you can unscrew the nut holding the piston to the rod, take the piston off, and pull the rod out of the end cap to replace the wiper seal in the end cap (darn, I just rebuilt my failed steering cylinder and I shoulda taken some pictures).
<font color="red"> Do you need to take any special measures to get the end cap off? Like heating it? If it unscrews, I would probably just put it in a vise with pipe jaws and use a pipe wrench on the end. Of course, that may not be so good if it is soft metal and the cap is locked on??? </font>
I did as you suggest and put mine in a vise and hauled away with a 24 inch pipe wrench - nothing moved. Then I got another 24 inch pipe wrench, put the cylinder on the ground, set the wrenches and jumped on the elevated one. Twice. And it gave way. Two hundred pounds applied at 24 inches with a good jump - how many ft-lbs is that anyway? I was afraid I might distort the cylinder but don't think I did - the end cap screwed back on easily (I haven't re-installed the cylinder yet for a leak test).
I'm not sure why I did this, but I'm now glad I did. At some point in my effort to loosen the cap (including some heating), I took out the hose fitting nearest the cap and found that the pipe threads of the fitting screwed into the cap threads a bit, locking the cap on. You might check for that before you jump on the wrenches and bugger the cap threads. I just got lucky.
Boy oh boy is the steering quick with only one cylinder! /forums/images/graemlins/tongue.gif
Sedgewood
Correct. Then you can unscrew the nut holding the piston to the rod, take the piston off, and pull the rod out of the end cap to replace the wiper seal in the end cap (darn, I just rebuilt my failed steering cylinder and I shoulda taken some pictures).
<font color="red"> Do you need to take any special measures to get the end cap off? Like heating it? If it unscrews, I would probably just put it in a vise with pipe jaws and use a pipe wrench on the end. Of course, that may not be so good if it is soft metal and the cap is locked on??? </font>
I did as you suggest and put mine in a vise and hauled away with a 24 inch pipe wrench - nothing moved. Then I got another 24 inch pipe wrench, put the cylinder on the ground, set the wrenches and jumped on the elevated one. Twice. And it gave way. Two hundred pounds applied at 24 inches with a good jump - how many ft-lbs is that anyway? I was afraid I might distort the cylinder but don't think I did - the end cap screwed back on easily (I haven't re-installed the cylinder yet for a leak test).
I'm not sure why I did this, but I'm now glad I did. At some point in my effort to loosen the cap (including some heating), I took out the hose fitting nearest the cap and found that the pipe threads of the fitting screwed into the cap threads a bit, locking the cap on. You might check for that before you jump on the wrenches and bugger the cap threads. I just got lucky.
Boy oh boy is the steering quick with only one cylinder! /forums/images/graemlins/tongue.gif
Sedgewood