Need help...JD 158 loader cylinder.

[cornstalk]

Hello board,

Recently purchased a 158 loader for my 4020 JD. The installation has gone pretty well up until today. Had everything tied in and hooked up....hit the bucket tilt valve, and a geyser of hydraulic oil erupted from the right side bucket cylinder. (Near the bottom at the 90 deg pipe fitting). Hoping it was just a matter of taking the fitting out and replacing or retaping it...I took the fitting apart....only to find what appeared to be a rubber band type item protruding from between the outer cylinder wall, and where the fitting screws into the cylinder. (Hope that all makes sense to you).

I'm assuming this is part of the seal / packing within the cylinder, and that it is going to need to be replaced. Am I going to have to pull the cylinder and take it into my dealer, or can I throw it on the bench and get er done myself. Moderately mechanically inclined, but never tore into one of these before. Anyone have any insight ??

 

[tom4018]

Are you sure that it is not the o-ring off of the fitting?

Even is the seals on the piston are bad it would not leak fluid externally. Depends on the type fiting they use but it probably has a o-ring to seal where it screws into the cylinder.

 

[cornstalk]

Wow, that would be incredibly easy.

When I removed the fitting however....there appears to be a very small (1mm) gap in between the outer cylinder wall, and an inner sleeve? This was apparent upon removing the elbow fitting and looking in at an angle. This "rubber" was sticking out of this gap on one side of the threaded hole. I pulled on it lightly, and it didnt seem to want to pull through at all. This made me think it was part of the internal workings (packing / seal). You maybe are correct....as I certainly didnt see any type of o-ring when I removed the fitting. (It appeared to have been teflon taped)

The fitting appears to be nothing other than a 90 degree 1/2 pipe thread fitting.

Thanks.

 

[KenB]

Wow, that would be incredibly easy.

When I removed the fitting however....there appears to be a very small (1mm) gap in between the outer cylinder wall, and an inner sleeve? This was apparent upon removing the elbow fitting and looking in at an angle. This "rubber" was sticking out of this gap on one side of the threaded hole. I pulled on it lightly, and it didnt seem to want to pull through at all. This made me think it was part of the internal workings (packing / seal). You maybe are correct....as I certainly didnt see any type of o-ring when I removed the fitting. (It appeared to have been teflon taped)

The fitting appears to be nothing other than a 90 degree 1/2 pipe thread fitting.

Thanks.

There is two different style of fittings used on cylinders,

One is a regular pipe fitting, it has tapered threads and is screwed in untill tight.

The other is a male boss type it has straight threads like a bolt it also has an O-ring seal and a locking nut on it.

Someone may have tried to put a pipe thread fitting on instead of the boss type.

 

[cornstalk]

There is two different style of fittings used on cylinders,

One is a regular pipe fitting, it has tapered threads and is screwed in untill tight.

The other is a male boss type it has straight threads like a bolt it also has an O-ring seal and a locking nut on it.

Someone may have tried to put a pipe thread fitting on instead of the boss type.

The fitting is as you describe, pipe like, tapered threads. The cylinder on the left side of the bucket has the same type of fitting without any apparent issues.

The rubber o-ring is protruding from within the outer cylinder barrel, and what appears to be an inner sleeve. Almost as though it's been forced through this gap from the inside. It also appears as though it may be significantly larger than an o-ring that would belong with the fitting itself.

 

[eric]

There will be an o-ring on the piston, which is the part that rides up and down the inside of the cylinder bore and is attached to the chrome rod. More than likely, somehow the piston was pushed back too far and the o-ring got caught on the threaded hole in the side of the cylinder barrel, thus pulling the o-ring out when the rest of the piston pushed back down on the downstroke.

Tearing a small lift cylinder down is no big deal as long as you have a decent vise and some common sense. The packing gland (the part at the top where the chrome rod goes through) will either be screwed on (hopefully) or welded on. Screwed on is no problem, welded on is a big problem. If welded, then u have to take it to a machine shop and have them cut the weld off so you can get to the piston to replace the seals. After removing the packing gland, then just slide the rod and piston right on out of the cylinder and replace the seals as needed. While you have it apart, go ahead and run some sandpaper around the holes in the barrel to remove any burrs which might catch the o-ring when you put it back together. I always use vaseline/STP oil treatment on the parts to make them slide in easier. Screw the cap back on and fill with oil and you are back in the lift business.

Good luck! If for some reason you get it apart and dont feel confident about putting it back together, then most shops will put it back together for you for about an hrs worth of labor. We generally allow 2 hrs labor + seal cost when rebuilding anything less than 4" diameter and less than 5 ft long. So you are looking at around a $150 bill if you take it somewhere and have it done.

 

[cornstalk]

There will be an o-ring on the piston, which is the part that rides up and down the inside of the cylinder bore and is attached to the chrome rod. More than likely, somehow the piston was pushed back too far and the o-ring got caught on the threaded hole in the side of the cylinder barrel, thus pulling the o-ring out when the rest of the piston pushed back down on the downstroke.

Tearing a small lift cylinder down is no big deal as long as you have a decent vise and some common sense. The packing gland (the part at the top where the chrome rod goes through) will either be screwed on (hopefully) or welded on. Screwed on is no problem, welded on is a big problem. If welded, then u have to take it to a machine shop and have them cut the weld off so you can get to the piston to replace the seals. After removing the packing gland, then just slide the rod and piston right on out of the cylinder and replace the seals as needed. While you have it apart, go ahead and run some sandpaper around the holes in the barrel to remove any burrs which might catch the o-ring when you put it back together. I always use vaseline/STP oil treatment on the parts to make them slide in easier. Screw the cap back on and fill with oil and you are back in the lift business.

Good luck! If for some reason you get it apart and dont feel confident about putting it back together, then most shops will put it back together for you for about an hrs worth of labor. We generally allow 2 hrs labor + seal cost when rebuilding anything less than 4" diameter and less than 5 ft long. So you are looking at around a $150 bill if you take it somewhere and have it done.

Eric: Thanks for the reply. Now that you mention it, when I lifted the boom (bucket attached) off of the trailer, the bucket by force of gravity did tip down farther than I wondered if it should. Live and learn.

The only thing that doesnt seem quite logical, is why the o-ring seems to be coming out from the gap in the outer cylinder barrel (tube) and what appears to be an inner barrel? If your looking into the hose outlet port on the cylinder at a 45 deg angle, you can see a very small gap between what appears to be two seperate barrels....this is where the o-ring is protruding from. Does this make sence to you?

Thanks again for the reply. I'll stop at my dealer and pick up a seal kit on my way home tonight. This makes me think it may be quite likely that the cylinder on the opposite side may have been damaged also....although it didnt seem to be leaking during my trial run last night.

 

[eric]

he only thing that doesnt seem quite logical, is why the o-ring seems to be coming out from the gap in the outer cylinder barrel (tube) and what appears to be an inner barrel? If your looking into the hose outlet port on the cylinder at a 45 deg angle, you can see a very small gap between what appears to be two seperate barrels....this is where the o-ring is protruding from. Does this make sence to you?

Not really, or at least on a tractor loader lift cylinder it does'nt.
The only reason you would have a tube inside another tube is if it was a telescoping cylinder, such as those found on forklift masts and dump trucks. That allows you to obtain 30 ft of lift height from a 10 ft cylinder. As soon as the first stage maxes out, then the next stage will extend and then the 3rd stage, and so on and so on. But the stages are hollow tubes, due to the weight involved, and they usually ride on bronze wear rings or bushings, not o-rings.
I've never taken apart a John Deere cylinder, (as far as I know), so I dont know if they put any sort of wear rings or anything in there, but the inner sleeve you see might just be some sort of limit device or spacer to keep the piston from ever bottoming out too hard should it be retracted too fast or has too heavy of a load. In most of those situations, the manufacturer will usually build in some sort of cushioning port which will slow the piston down before it crashes through the gland, but Derre might have their own design. If this is a factory cylinder, then you could probably call a dealer and ask their service manager about this, especially if you are gonna buy the rebuild kit from them.

 

[cornstalk]

Not really, or at least on a tractor loader lift cylinder it does'nt.
The only reason you would have a tube inside another tube is if it was a telescoping cylinder, such as those found on forklift masts and dump trucks. That allows you to obtain 30 ft of lift height from a 10 ft cylinder. As soon as the first stage maxes out, then the next stage will extend and then the 3rd stage, and so on and so on. But the stages are hollow tubes, due to the weight involved, and they usually ride on bronze wear rings or bushings, not o-rings.
I've never taken apart a John Deere cylinder, (as far as I know), so I dont know if they put any sort of wear rings or anything in there, but the inner sleeve you see might just be some sort of limit device or spacer to keep the piston from ever bottoming out too hard should it be retracted too fast or has too heavy of a load. In most of those situations, the manufacturer will usually build in some sort of cushioning port which will slow the piston down before it crashes through the gland, but Derre might have their own design. If this is a factory cylinder, then you could probably call a dealer and ask their service manager about this, especially if you are gonna buy the rebuild kit from them.

Eric,

Thanks for your help in this matter. Got er taken care of yesterday. After a great deal of headaches, I discovered the cylinder was NOT a JD cylinder. (Something that had been robbed from elsewhere, and painted in JD green to match the loader quite a few years ago.)

Anyway, never did determine what brand of cylinder it was....but was able to match up o-rings at the local case IH dealer.

The inlet/outlet fitting screwed into the endcap/wiper assembly. The endcap was about 4-6" long, giving the illusion of an "inside sleeve" before dissassembling. Installed new endcap seals, packing/piston seals, and wiper seals. Put her all back together, and mounted back on the loader.....only to start up the tractor and find that the bucket no longer leaked, but had a bad creep. (Assumed it to be the other cylinder as the first one had just been overhauled). So, got to do er all over again....the second one went much faster.... :cboy: [/quote]