Loader Level of difficulty to change lift cylinder seal?

[marsan0917]

Can the upper seal on the lift cylinder of a L480 loader be changed out by the consumer or is there extreme pressing to be done making it a Kubota service job? This is on an L480 loader attached to a L2900.

 

[leonz]

Can the upper seal on the lift cylinder of a L480 loader be changed out by the consumer or is there extreme pressing to be done making it a Kubota service job? This is on an L480 loader attached to a L2900.

If you are dealing with oil blowing through
the wiper seal, you have major repair issues
and you need to have both cylinders rebuilt
by a hydraulic repair shop.


Hopefully they own a hydraulic cylinder
rebuilding machine.

 

[kennyd]

If you are dealing with oil blowing through
the wiper seal, you have major repair issues
and you need to have both cylinders rebuilt
by a hydraulic repair shop.


Hopefully they own a hydraulic cylinder
rebuilding machine.

I sure hope your joking...


marson-
Rebuilding cylinders is fairly easy, there are a lot of threads in the Hydraulics forum about it. If you post pictures of the cylinder we can tell you how to take it apart.

 

[kuboman]

Rebuilding a cylinder is not a big deal. Once you determine how they come apart it is quite easy. It does help to have an impact wrench to get the nut off that holds the piston on but not necessary. It can be tricky getting the piston back in the bore without ruining the new seals.

 

[leonz]

Rebuilding a cylinder is not a big deal. Once you determine how they come apart it is quite easy. It does help to have an impact wrench to get the nut off that holds the piston on but not necessary. It can be tricky getting the piston back in the bore without ruining the new seals.

AS I said it is better to have someone
equiped to do the job do it for you as
tearing a piston seal is a very expensive
part of the learning curve.

When a wiper seal is shot it always leads
to a larger problem with a bent cylinder rod
in most cases.

Yes- I have rebuilt and repaired hundreds of
hydraulic cylinders on mining machinery.

 

[rScotty]

Can the upper seal on the lift cylinder of a L480 loader be changed out by the consumer or is there extreme pressing to be done making it a Kubota service job? This is on an L480 loader attached to a L2900.

It's not a difficult job, but can be an oddly tricky one. The first problem is holding the cylinder and later the piston rod or piston very tightly without distorting them. You have to hold them tight to turn the big nuts, but you cannot squeeze either one even slightly to restrain them or the part will be ovaled and ruined. The nuts tend to be on very tightly. So it is necessary to make up some strong jigs for holding things rigidly and safely while the big nuts are undone. The rig for doing that in most shops is metal, roughly the size of a table and looks like an engine stand. A big lathe will work too.

The actual swapping of the piston seal and the end cap seal takes only moments and seals are reasonably priced. When sliding the piston rod through the new end seal it is usually necessary to pass the threaded rod through the seal and that is where problems can happen. Any nick on the lips of any seal is a leak. After putting the seal around the piston rod, there is a seal on the piston itself and then the piston with the new seal on it is slid back into the barrel of the cylinder. When doing that it is necessary to guide it over sharp internal threads of the cylinder end without galling or slicing the rubber seal at all. I have a roll of very thin smooth stainless steel sheet (about .001") used to make sleeves to do both of those things.

So you see, some people say it is a simple job....and it can be. In fact, it always is simple if those special tools are in place. It's a simple job for a well-equipped shop. I usually charged 50 to $100 labor for doing it, and didn't cry if I messed up a seal or two before I got a set in that pleased me.

It is certainly a job that a good home shop can do...but will require some thought and making up some special tools to hold things. There's a big temptation to grab the cylinder in a vise or with a wrench and both of those tend to lead straight to a ruined part. But if you can get past those hurdles and get the nut off the end of the cylinder and off the end of the piston without damage, there's usually some thin film or sheet of plastic or something around the house that can be adapted to make a sleeve for installing the seals. Old photgraphic roll film might make a decent sleeve. Tin foil isn't going to be stiff enough and roof flashing is too rough and too thick anyway.
Good Luck, rScotty

 

[funwithahoe]

Spent a ton of time once rebuilding the loader cylinders on a JD backhoe. If you can get someone with the correct tools to do it for 50-100/hour you will be way ahead because of what the last poster stated - It is easy if you have the right tools - We did not.

When we reinserted the pistons with the new seals the fit was extremely tight and without a press it is very difficult to get them in without nicking the new seals. A hammer just don't work like a press does!:laughing:

In the end, we figured the cylinders worked about as well or maybe a little worse than before we started. The frustrating part about it is that the seal change is actually extremely simple and straight forward. Getting them apart and back togther (especially back together) can be a bear!!

Good Luck!

 

[kuboman]

One little trick for getting seals over threads or grooves is to stretch cellophane over the threads to keep them from nicking the seals.

 

[radioman]

Hopefully they own a hydraulic cylinder
rebuilding machine.

really-whats a hydraulic cylinder rebuilding machine do? You stated you done hundreds of mining equipment and I really don't think its that much different then tractor hydrualics except mining is supersized stuff. I think any homeowner can do 6 inches bore and smaller themselves.

I am not an expert by any means, but I done a couple rebuilds. One for a wood DA splitter, and other for SA plow cylinders. After doing them, I thought it was a pretty much a easy thing to do. its a matter of taking it apart and take the piston to the local hydraulic shop for new seals and rings. Only tool I needed at the time was a double pin type of wrench for woodsplitter ram. I just made a wrench with a 120v welder and angle iron and cut off bolts for pins.

Like kenny says, a pic of your rams can say 1000 things about it

 

[crazyal]

I've done a dozen or so. The easiest way I found is to loosen the gland nut while the cylinder is still in the tractor. If it's an older machine chances are the seal is just old and lost it's elasticity. If one's bad you can count on others also going so you might as well learn how to do it now and save money down the road.

I have a large 4' pipe wrench for the gland nuts that only have a small hole for the special wrench to fit in and a horrible freight 4' adjustable for the type that have either flat spots for a wrench or have 6 sides like a nut. Buy your first set of seals from a dealer and ask them how they do it and for a picture showing the correct order, usually they are very helpful. Just clean everything well and use lots of lube and be careful not to damage the seals.