hamholfarm
New member
- Joined
- May 16, 2008
- Messages
- 4
Hello,
I have a JD 970 Sub-Compact Tractor and I have a 55 gallon, 3-point hitch, field sprayer attached. Earlier this spring as I was prepping the sprayer for the season, I noticed the on/off valve had broken. The tip of the seat on the plunger was made of plastic, and it had crumbled, probably from the chemicals. So I went to the store and purchased a new valve which is properly called a Control Valve. Well, of course the design had been changed! I had to buy all new fittings and design and build a new mount for the changed valve, no real big problem, just a hassle. So when I tried to use the sprayer last week, I had no flow coming out of the nozzles! I immediately thought the new control valve had to be the cause, so I disassembled the valve but could find nothing wrong with it. I next figured it had to either be the pump or the variable Pressure Relief Valve that was the problem. I learned that if I backed the pressure relief valve all the way out, so as to have basically zero pressure, I would get a slight flow out of the spray tips. So now I know the lines are not plugged because I am getting some flow. I then looked in the tank and I could see that the recirculation line into the tank was flowing at what looked like normal flow. Hmm, is the pressure relief valve bad I thought? So I replaced the pressure relief valve with a new one, which again had been redesigned! So back to the store to buy more fittings! Once I had all the lines plumbed again, I gave it a try and wham - I still had the same problem! I had no flow out of the spray nozzles unless I backed the pressure relief valve all the way out, and then I would get a very small stream of water. So now I am thinking the 6 roller pump has to be bad. I disassembled the 6 roller pump and everything inside looked good. Just to make sure, I measured the rollers and compared to their spec they where at the most 0.020 inches out of spec. I did not think the pump was bad, but I could not figure out anything else that could be wrong. So I purchased and installed a new 6 roller PTO pump. I also installed a new pressure indicator just for good measure. I fired up the tractor ands turned on the sprayer and bam it still did not work correctly! Now I am really pissed, and confused! For a last resort, I switch the recirculation hose with the in-feed hose to the pump, thinking maybe there was a restriction from the bottom of the sprayer tank. It made no difference at all. Still scratching my head, I called the local JD dealer. I asked if there was any way that the rear PTO of the tractor would not spin at the correct 540 rpm if the throttle is correctly set. The answer was no, the PTO runs off of a gear set, there is no clutch type assembly to slip. So now I am totally pissed, down $250, and am completely stumped!
Pictures of the parts used can be seen by following this link:
3 Point Field Sprayer pictures by hamholfarm - Photobucket
Any help would be greatly appreciated!
Thank you,
Chip
I have a JD 970 Sub-Compact Tractor and I have a 55 gallon, 3-point hitch, field sprayer attached. Earlier this spring as I was prepping the sprayer for the season, I noticed the on/off valve had broken. The tip of the seat on the plunger was made of plastic, and it had crumbled, probably from the chemicals. So I went to the store and purchased a new valve which is properly called a Control Valve. Well, of course the design had been changed! I had to buy all new fittings and design and build a new mount for the changed valve, no real big problem, just a hassle. So when I tried to use the sprayer last week, I had no flow coming out of the nozzles! I immediately thought the new control valve had to be the cause, so I disassembled the valve but could find nothing wrong with it. I next figured it had to either be the pump or the variable Pressure Relief Valve that was the problem. I learned that if I backed the pressure relief valve all the way out, so as to have basically zero pressure, I would get a slight flow out of the spray tips. So now I know the lines are not plugged because I am getting some flow. I then looked in the tank and I could see that the recirculation line into the tank was flowing at what looked like normal flow. Hmm, is the pressure relief valve bad I thought? So I replaced the pressure relief valve with a new one, which again had been redesigned! So back to the store to buy more fittings! Once I had all the lines plumbed again, I gave it a try and wham - I still had the same problem! I had no flow out of the spray nozzles unless I backed the pressure relief valve all the way out, and then I would get a very small stream of water. So now I am thinking the 6 roller pump has to be bad. I disassembled the 6 roller pump and everything inside looked good. Just to make sure, I measured the rollers and compared to their spec they where at the most 0.020 inches out of spec. I did not think the pump was bad, but I could not figure out anything else that could be wrong. So I purchased and installed a new 6 roller PTO pump. I also installed a new pressure indicator just for good measure. I fired up the tractor ands turned on the sprayer and bam it still did not work correctly! Now I am really pissed, and confused! For a last resort, I switch the recirculation hose with the in-feed hose to the pump, thinking maybe there was a restriction from the bottom of the sprayer tank. It made no difference at all. Still scratching my head, I called the local JD dealer. I asked if there was any way that the rear PTO of the tractor would not spin at the correct 540 rpm if the throttle is correctly set. The answer was no, the PTO runs off of a gear set, there is no clutch type assembly to slip. So now I am totally pissed, down $250, and am completely stumped!
Pictures of the parts used can be seen by following this link:
3 Point Field Sprayer pictures by hamholfarm - Photobucket
Any help would be greatly appreciated!
Thank you,
Chip
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