rebuilding lift cylinders on Deere 420 Loader

[Wayne_H]

OK, my 420 loader on Deere 4400 would not stay up. Not just not stay up, it would drop six inches in two minutes. It did't happen with my snow plow, so I figured it was not the valve on the tractor, but internal leaking of the cylinder. This is loader serial number 017441. For that serial number the right part is AH176273. There are only two different kits for this loader, this is the later one.

Now inside the kit is this orange split thing. That is the tool you need to take the cylinder apart. You take off the "C" clip on the cylinder and push that part inside the cylinder until you see the machined slot. That orange thing goes into that slot and lets you pull the cylinder apart. Without that, good luck.

When it comes out, it looks like this. The last pic is of the O rings. The yellow one in the lower right with the O ring inside is what actually goes on the aluminum piston. The inner O ring keeps that yellow thing against the wall of the cylinder. If you look at the O ring with a chunck out of it... That chunk was missing, so this cylinder really had no chance of working right.. God knows where that chunk went.

There are also two seals that get replaced, no pics of them, but they are a PITA to get the old ones out, and an equal PITA to get the new ones in..

Wayne

 

[J_J]

Is there a question here or did you just go ahead and rebuild the cyl. Cylinders fail for different reason, and one of the main reasons, is that parts just get tired. Heat could have ruined it, the composition of the seal could have deteriorated.

 

[Wayne_H]

Is there a question here or did you just go ahead and rebuild the cyl. Cylinders fail for different reason, and one of the main reasons, is that parts just get tired. Heat could have ruined it, the composition of the seal could have deteriorated.

Not sure I understand your question, but the loader was not staying where I put it, it sank to the ground way faster than it should have.

Wayne

 

[kennyd]

Did they have those kit's in stock? Thursday when I talked to you it seemed you where SOL:laughing:

 

[J_J]

I think we have a communication problem. I simply ask if there was a question you had. From your statements, I gather you found the problem and fixed it.

One might say something like this, I had a problem, found the cause, and ordered the parts, and fixed it, and it now works as it should.

If that fixed everything, then good for you.

 

[Bison]

Well?
Did it fix it or?

Dropping loader arms is usually a leaky/worn control or load valve,unless the cylinder gland seal leaks to the world.
With a good tight valve the loader would not lower even if the piston seals are shot,but it would not raise very fast if at all cause oil under pressure would bypass the piston from the pressure side to the return side.

 

[Grayson Klassen]

I have a JD 148 Loader and I just oredered kits for the bucket cylinders, unfortunately not because they are bypassing but rather a leaky rod seal. So I figured if I go to all the work for a rod seal I might as well rebuild them entirely.

No this isn't a question, just a statement

Not sure I might be looking for sympathy :laughing::laughing::laughing:

 

[Wayne_H]

Did they have those kit's in stock? Thursday when I talked to you it seemed you where SOL:laughing:

Ken:

They sent me the wrong kit Thursday. Deere still has the truck that leaves the distribution warehouse in Canada every night after COB and drops parts off on the East Coast the next day, so they had the right parts in Saturday AM.

Bison, yes it fixed the problem. Good as new now.

Wayne

 

[Rocwin]

Like JJ said, there could be a number of reasons why the cylinder was dropping. Seal age or wear, defective counterbalance or control valves, or internal bypassing due to damage of the cylinder. In the last case if you cylinder barrel is worn or damaged internally a new set of seals may fix the problem for a little while but as the seals keep passing those areas they'll wear our quicker and bypass sooner than you'd expect. When rebuilding a cylinder don't just replace parts, find out why it was leaking or bypassing; only by finding and fixing the root cause can you actually repair the problem.

 

[kennyd]

Like JJ said, there could be a number of reasons why the cylinder was dropping. Seal age or wear, defective counterbalance or control valves, or internal bypassing due to damage of the cylinder. In the last case if you cylinder barrel is worn or damaged internally a new set of seals may fix the problem for a little while but as the seals keep passing those areas they'll wear our quicker and bypass sooner than you'd expect. When rebuilding a cylinder don't just replace parts, find out why it was leaking or bypassing; only by finding and fixing the root cause can you actually repair the problem.

I think he did find the problem...

From the original post:

If you look at the O ring with a chunck out of it... That chunk was missing, so this cylinder really had no chance of working right.. God knows where that chunk went.