Boom Cylinder Dripping - Need Advise.

[kennyd]

The system is self-purging, so all you need to do is operate the control and cycle the cylinder several times in and out. Recheck fluid level when your done also.

 

[Tractor Pilot]

So I rebuilt the right boom 1.5" cylinder on my model 70 loader. I purchased the JD seal kit #AM118391. The kit came with step-by-step instructions.

After I removed the cylinder from the tractor, I drained the cylinder of fluid by exercising the rod back and forth. I mounted the cylinder on my bench vise and began the disassembly.

After I removed the snap right, I pulled on the rod and the entire rod assembly, including the gland, came right out of the cylinder with no problems. I removed the nut on the end of the rod assembly (it was on very tight; about 200lb-ft with lock tight) and removed the piston and the gland. The inside of the cylinder and all the components of the rod assembly appeared to be in good shape (no scratches, gouges, burrs, etc.).

I replaced a small o-ring on the rod just above the threads (not pictured) and replaced the seals on the piston and the gland. The model 70 loader can come with two types of glands - an aluminum or a cast iron. I had the cast iron gland. Some of the seals on the gland were tricky to remove and replace (rod seal inside the gland and a precision fit metal-backed wiper seal). I soaked all the seals in very hot water for about 5 minutes then quickly dried them off and coated them with hydraulic oil to make installing them easier.

After all the seals were replaced, I reassembled the rod assembly and tightened the nut to 200lb-ft after having added lock-tight. I installed the rod assembly back into the cylinder and installed a new snap ring.

I reattached the cylinder to the loader; cycled the loader several times to bleed out the air; and so far no drips or leaks!

 

[Tractor Pilot]

Here are some additional pictures. The first is the rod assembly (the nut is removed). The second is the piston with the new seals. The third is the gland with the new seals.

The fourth picture is a schematic of the cast iron gland and its seals. Notice seal "C" (the rod seal). It sits in an interal groove. One side of that seal has an extention that stick out slightly (see the point in the picture on the left side of seal "C") and seals tightly against the rod.

When I examined my old seals, they all appeard to be in good shape. But on closer examination of seal "C" (the rod seal), that slight extention was worn away. I suspect that was the source of my dripping.

Thank you all for your help and advise on this project. It was my first time resealing a hydraulic cylinder. It appears to have been a complete success.

Bruce

 

[kennyd]

Great stuff TP, thanks for sharing:thumbsup:

 

[TTTTTT]

Thanks for sharing Bruce and documenting. Not a JD, but will doing the exact same for my drooping curl cylinder(s) soon. I've have been told I can also leave the cylinder on the loader just removing from one end using the still attached as an anchor. I think I would rather do it in a clean controlled spot so I don't wreck anything as I am re & re'ing it. Thoughts?

Dave

 

[MichMan]

Thanks TP! Getting ready to rebuild the cylinders on my Model 70 also.

 

[TyJD]

I am tackling this same project myself and I was hoping you could tell me how you removed the metal backed wiper seal on the gland. I also have the seal inside the gland to replace but so far dental picks have worked for everything else.

 

[wdchyd]

Thin flat head screw driver driven in between the wiper and the gland (from the inside)......then twist the screwdriver, it'll pop right out

 

[TyJD]

Perfect, that worked like a charm. Thanks wdchyd.

 

[sanchezm]

Hello, could you please post or send me a pdf file of the John Deere seal kit instruction sheet shown in one of the thumbnails of this post. I am buying an aftermarket seal kit and don't know if it will include the step by step instructions. Thank you. Mark