Hello, I have a 310D that I am trying to slow down the leaks on. The big ones are some of the cylinders, where I am replacing the seals, as well as the rods on the stabilizers. I repaired a crack along the weld at the bottom of the hydraulic tank a few years ago. The last significant leak(s) I have to work on are at the loader control valves. I have the Husco valves. I have the JD service manual but it does not provide great information about these valves. Additionally, many of the detailed diagrams are not legible in the digital manual I have. Does anyone have a good manual for repairing these valves? Any good sources for seals and other parts? The leak(s) look to be in the lower end. I have attached a PDF of one of the diagrams that is legible in my manual. I suspect the O-ring "P" has failed. Does anyone know if the long cap and parts can be easily removed with the valve assembly in place on the machine so the "P" O-ring can be replaced? Thank you in advance, John
I did some more looking and found some information on the JD parts website. It looks like there are just a few seals to replace. They come in a JD kit AT168675. Unfortunately the kits are rather rare and expensive. I found some information on the Husco website. Reference the spool valve seals: Note: The “Zero Leak” seal arrangement contains a lip seal that requires a special tool and procedure for its installation in the field. Consult factory for this procedure. The machined groove for spool end seals did not change to accommodate the “zero Leak” arrangement. Therefore, the previous P/N 571 O-ring and P/N 4137 back-up ring combination can be used. These are still used on the end mechanism kits for ease of field installation Some more work found a national stock number (NSN) reference to the 571 O-ring. it appears to be a standard -210 , 70 Duro, NBR, O-ring. I already have some of those in my shop. I am still working on the 4137 wiper, although there may be some different suppliers according to NSN data. I do not want to tear into the valves until I have replacement parts on hand as I suspect the old seals are rather deteriorated. Some of the seals I the cylinders just crumble onto pieces when I pull the gland and piston out.
If it's like the rear Husco valves on my E model, "P" will be hard wiper seal and "Q" will be a lip seal. It's way different from an O-ring. You'll probably have to buy that part number from Deere and it'll come in a baggy with 100 other seals. Throw 96 of them away and use the 4 you need. If you find a way to purchase those a la carte, let me know. Might check Ebay for some old stock.
If you end up with the hard plastic seal you will need the special tool almost impossible to to install without damage without tool. Be sure to torque those valves when installing I believe torque was 26 to 30 foot lbs so the metal taper will be seated in valve housing.
I am waiting for some AN wipers I ordered to arrive to see if those will work. The link below has some information from Husco, see page 4. https://www.hydraulicdistributors.com.au/downloads/2019-product-brochures/Husco.pdf Note: The “Zero Leak” seal arrangement contains a lip seal that requires a special tool and procedure for its installation in the field. Consult factory for this procedure. The machined groove for spool end seals did not change to accommodate the “zero Leak” arrangement. Therefore, the previous P/N 571 O-ring and P/N 4137 back-up ring combination can be used. These are still used on the end mechanism kits for ease of field installation
I'm reasonably sure those o rings can be replaced easier on the machine than removing the valve. You have the o rings, take it apart and see, the bottom end won't have a wiper, just an o ring because there shouldn't be dust in there. The "zero leak" seal is the least of your worries, new o rings should eliminate any wet seepage and work fine for the life of the machine most likely.
It finally quit raining and I had a little time to look at the valves. My loader valve was the one leaking. Here is what I found. The lower end, opposite the linkage, only had a wiper. The upper end near the linkage had two all rubber U-cup seals. These measured approximately 1.0" in Diameter and the height was .210. .250 would be a common height for these seals. It may be that they are somewhat compressed. No metal in any of the seals and no O-rings. The AN wipers I have are a bit larger in diameter, rim thickness, and overall height. The upper one went into place easily. I had to work the lower one into place. There is not room to place a -210 O-ring behind the wiper in the lower end of the valve. In the upper end I placed a -210 O-ring and a wiper under the retaining plate. I ran it for a few minutes to check normal operations. So far there are not any leaks but I only ran it for a few minutes. I will update on my results after I run the loader for a while. It may be some time before I am home to do that. I ordered the O-rings and wipers from the O-ring store. FDAB70210 20 3/4"ID X 1"OD X 1/8"CS $0.13 $2.68 AN-05-SH 12 $0.57 $6.84
What I found when I took the valve apart was not making sense to me. I would have expected one of the U-seals to be on the lower end and one on the top end. When I got home tonight I took the valve back apart. I also tried to removed the round stub that stuck out of the lower end. This stub came out and I found the remnants of a very badly deteriorated O-ring. Besides being able to replace the O-ring, a -20, having it removed also made it easier to see how things went together. For now I put what I think is the better of the two old U-seals in the lower end. I left the O-ring and the wiper in the upper end. From the measurements I took it seems like a .210 high U-seal would be appropriate. That is about what I measured the height of the old ones. So far the closest I can find is .250 Maybe these will squeeze down. I might also be able to use an O-ring with a backer. The rim of the AN wipers I have, added to the -210 O-ring comes out to .220 inches. I might be able to make a combination of them work as well. Now all I need is some time at home to work on this.
Several hours on it an no leaks.