loader cylinder seal failure.

   / loader cylinder seal failure. #1  
H

homedad

Silver Member
Joined
Aug 29, 2009
Messages
129
Location
central/ se michigan
Tractor
Kubota L3130DT
I have the LA513 loader on my L3130dt. About a year ago my experienced neighbor and I replaced the seals on the cylinder which tilts the bucket. The light blue seal was actually coming out where the rod enters the cylinder. Now the same thing is happening on the same cylinder. Anyone know why? The rod was flawless on inspection when we took it apart last year. I've been lifting heavy logs with a set of forks recently. Could this have caused this? Thanks.
 
   / loader cylinder seal failure. #2  
dump cylinder whoopsies;


homedad said:
I have the LA513 loader on my L3130dt. About a year ago my experienced neighbor and I replaced the seals on the cylinder which tilts the bucket. The light blue seal was actually coming out where the rod enters the cylinder. Now the same thing is happening on the same cylinder. Anyone know why? The rod was flawless on inspection when we took it apart last year. I've been lifting heavy logs with a set of forks recently. Could this have caused this? Thanks.
Click to expand...

About your cylinder and the reason it failed has many parts unfortunately.

The cylinder was purchased from a supplier and made part of the entire system.



The rod wiper which is the outer seal acts as a dust and dirt seal.



It involves linear mechanics and the stresses that go along with them, which it is how the cylinder works.


And as the stuffing box
and piston are small in length-height-surface area it does not provide much strength/surface area to support the cylinder rod when working.


the stress of lifting the logs and rolling the forks back and forth caused the rod to bend and the barrel to become egg shaped which has ruined the cylinder-

A rod seal will not pop out if it is installed properly and greased when the the rod is passed through it.

The piston and rod became bent when under load and then the rod seal popped out( you may or may not have a leaking stuffing box under the rod wiper).

This occured for the following reasons;

the extended loading created pressure to bend the rod while under motion and as a result cause the cylinder to arch and become egg shaped due to the bending.


If a stop tube was installed between the stuffing box that was properly sized in length being 1 inch in length for every foot of extended length adding one inch for any length below one foot it would not have bent and become egg shaped.

The stop tubes are made of bronze or steel and are slightly smaller in diameter than the piston of the cylinder and this creates a much larger surface area to distribute the lateral and linear stresses over the entire surface area of the piston stop tube and stuffing box.


I have to run but the cylinder should be replaced with one that has a stop tube or the same thing will occur- remember 1 inch per foot of extended length and another inch for any additional lenght short of the 12 inch mark
 
   / loader cylinder seal failure. #3  
LEONZ, you seem to be the expert on everything, but what made you decide the rod is bent and the "barrel to become egg shaped which has ruined the cylinder"? Perhaps you have seen the cylinder already and I have not.
 
   / loader cylinder seal failure.
  • Thread Starter
#4  
Can I assume that if the barrel is now egg shaped, the end cap won't unscrew?
 
   / loader cylinder seal failure. #5  
The stuffing box will not be worth saving unfortunately
in any case.:(

If you pull it apart you will see the scuff damage on the bottom edge
rod scraping into the stuffing box bronze wear surface if bronze is used
as wear material




Dependent on your time constraints you may want to order
a new cylinder from a hydraulics repair shop with a stop tube OR
order a replacement cylinder and visit a machine shop
and ask to have a stop tube made and properly sized in length for the cylinders fully extended length which will shorten the stroke by at least 3 inches if the rods extended length is 2 feet plus and have the dealer install it in the cylinder to stop the problem if you have a lot of logs to move.


Oh and the bore of the stop tube can be 1/32 larger than the rod diameter.
 
   / loader cylinder seal failure. #6  
loader cylinder continued:


638 said:
LEONZ, you seem to be the expert on everything, but what made you decide the rod is bent and the "barrel to become egg shaped which has ruined the cylinder"? Perhaps you have seen the cylinder already and I have not.
Click to expand...

Thank you for the compliment and I will continue to keep my head out of my butt:laughing:

This happens with mining equipment where a singe cylinder is used to control a digging bucket on underground mining scoops and they dont bother with improving themm or upgrading the cylinder parts.



The shovel operators will keep digging because they are not payin attension to anything but the need to fill the bucket and in the end the cylinder will suffer any of the following fates

a. the rod eye will snap off

b. the cylinder rod will break the rod eye weld and flatten the steel that the weldment is made of like a pancake while retracting the cylinder rod.

c. the cylinder and rod will bend in an arc and become scrap metal as the individual parts-

a. barrel
b. packing gland, packing gland locking ring and rod wiper
c stufffing box
d. cylinder rod
e. piston halves
f. barrel end swivel bearing
The only undamaged part left is the castle nut that holds the piston halves together.

continued:
and are ruined from the damage and force.


We had one mechanic so disgusted with a bad cylinder that he could not disassemble that he filled it with acetylene and oxygen and fired it off and the rod packing gland and piston launched themselves over 150 feet from the main shop repair bay and the explosion could be heard and felt on the upper level of the mine.


Not the kind of thing that you want to do at home mind you- it ranks right up there with goosing a tire with some acetylene to get the bead to seat on a tubeless tractor tire.



They refused to buy a tuxco cylinder repair machine that disassembles and assembles cylinders because it was not a justifiable expense even though we had hundreds of hydraulic cylinders in use and still do.
 
   / loader cylinder seal failure. #7  
638 said:
LEONZ, you seem to be the expert on everything, but what made you decide the rod is bent and the "barrel to become egg shaped which has ruined the cylinder"? Perhaps you have seen the cylinder already and I have not.
Click to expand...

What makes you say this is a compliment?.......:confused2:
 
   / loader cylinder seal failure. #9  
I too had a cylinder seal leaking after about 70-odd hours of operation. It looked to me like the inner lip had become "flipped" outward.

Kubota fixed it under warranty, the service tech mentioned they had had a few issues with seals in the past.

Sean
 
   / loader cylinder seal failure. #10  
Don't stop tubes result in a longer overall cylinder dimension? If so how do you fit in place of the OEM unit?
 
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