[Ss313]

I acquired a 317 with a Johnson 10 TC loader a few years ago. I have fumbled through its issues but have come to one that is over my head. I have replaced the cylinders and gotten more lifting ability but I think that I need to replace the valve assembly to get rid of what I think is excessive drift. I don’t know what to buy. I don’t know what gpm the pump is and I don’t know if I need open or closed center. My valve doesn’t have a float position but some that I have seen do. Would that be a worthwhile upgrade?
Any help would be much appreciated.


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[TUDOR]

- What size cylinders did you use?

- New or used?

The lift cylinder size (bore and stroke) determines the pump size required.

Additional lift capacity is usually easier to achieve with a modest adjustment of the relief valve than with a change of cylinder size. There is a limit to how much a GT FEL can lift due to the weight of the tractor and associated ballast. The loader on my GT can easily lift over 1000 lb of payload with the original 2x18 cylinders and 650 lb of ballast. I've never adjusted the relief valve from its original position.

Excessive drift is usually caused by poor cylinder (piston) sealing.

While I do recommend that the lift cylinder valve should have a float position, I have rarely even thought about using it with my loaders in almost 4000 hours of operation. It's usually been a PITA on the rare occasions that I have tried it. Others have used it successfully on a regular basis. It depends on what you are doing with the bucket.

 

[JP Savage]

Would it help the "drift" if the control valve was gone through replacing the O rings?

 

[TUDOR]

Nope. The O-rings are to keep the fluid in and the dirt out. They are at the ends of the spools, past the working (pressure) portion. Close spool to valve body clearances limit the amount of fluid that they have to deal with, but worn out O-rings will allow that fluid to pour out, usually onto your boot.

While wear in the valve can cause a cylinder to drift, it is a rare occurrence. The first suspect is always the piston seals.

 

[Ss313]

I will have to find the cylinder sizes but they were as close to stock as I could get from Bailey’s and they were new. I’ve had the valve apart and you are correct about the orings. The pistons and cylinders didn’t look too bad but there was noticeable play between them. I was assuming that the fluid was bypassing in the valve because of the wear.


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[Ss313]

The tilt cylinders are 1.5 x 10 and the lift cylinders are 1.5 x 16..


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[TUDOR]

I was assuming that the fluid was bypassing in the valve because of the wear.

The spools are polished steel, and sometimes chrome plated. The valve bodies are cast iron or machined aluminum with the spool bores honed to fit, and the moving parts live in an oil bath. Ten thousand cycles may show a slight discolouration or hazing on the spools. I probably have about three times that many cycles just clearing snow from my driveway over the years, and I have usually done 4-7 other driveways as well. Add to that all the summer projects for 20+ years and there are close to 100,000 cycles on my GT loader valves.

Spool valve wear has never been a problem.

The rubber seals on a piston bear against the cylinder wall under pressure. Even with an oil film, there is going to be wear over time and the seals have to be replaced periodically.

 

[Ss313]

I did finally replace the loader valve. It made a big difference. I assume that a 10TC is for a 110 or 112 which would make it from the late 60’s or the 70’s. I have no idea how many cycles that valve may have seen but I think it did it’s job and I have no complaints about having to replace it.
Another factor in having to replace it is the substance that resembled very dirty hydraulic oil. I changed it and cleaned the reservoir when I bought it thinking that it might help. I know that it didn’t hurt.

Even with this I am in no danger of lifting the rear of the tractor. I guess I need to look at pumps now. I’ve gone this far I may as well finish the job.


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[Ss313]

As a follow up just in case someone in the future sees this thread I did replace the pump. I think I’m happy with it now and can put off buying a larger tractor for the time being.
With the new pump it can lift things that I wouldn’t have thought of trying in the past. It can also lift the rear of the tractor very easily now.
Next on the list is probably a pin style quick disconnect for the bucket and a set of mini forks for it.

Parts list

.37 cu in hydraulic pump from Surplus Center

2 spool 10 gpm Bailey loader valve

1.5 x 10 Bailey curl cylinders

1.5 x 16 Bailey lift cylinders


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