Green Tractor Talk banner
1 - 20 of 22 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter · #1 · (Edited)
6420 with 4k hours. hydraulic oil filter changed 10 hours ago. i wasnt in the tractor when problems started. It was a family friend who is almost deaf, so if a noise occured during the problem then he didnt hear it.

We were running a 7200 planter with the vaccuum hooked up to a valve and the return going into the back of the sump for a no restricted return. first year doing this. we tried to get a motor return kit from john deere but not tech knew how to hook it up. so it is just dumping right into the sump. 4 total valves with 2 dedicated strictly to the loader.

problem started when the vac was on and when the planter was lifted to turn, it robbed flow from the vac. so the valves were swapped between the lift lines and vacuum lines, and it worked correctly for another 30 minutes then happened again. any valve that is used robs from the other. the vacuum is only using 5gpm. we planted 300 acres so far and had no issues.

pressures tested at 2950 psi, and sump screen filter was cleaned only having 15% debris blockage. no lights or warning flashed or buzzed. no unusual sounds or anything. could it be a fuse issue? i found it odd that no warning light came on.

the tractor was driven to a shop 10 miles away where it is currently undergoing tests and they have not found the problem yet. repair man says it might be something under the cab where he has to tilt the cab to get to.

any suggestions or questions? is the return from the vacuum dumping into the sump starving the secondary pump of clean hydraulic fluid from the clean hydraulic fluid sump. the sump return is right beside the top link mount. im kinda new to this tractor and theese hydraulics. please help thanks
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #2 ·
this is from a 8000 tractor. if the vac return is the issue then can someone tell me how to hook it up? i dont see it being my problem since we have planted 300 acres so far.... why would it be a problem now.
 

Attachments

·
Registered
Joined
·
84 Posts
You just showing low flow, or no flow. They make flow gauges and I checked mine for using a hydraulically drive snow blower. I have the high flow pump on mine. I used power beyond setup and also teed the return to also use the return svc. I found that some quick connect fitting are not rated for the flow I was putting though them. Just my two cents

Sent from my LGLS990 using Tapatalk
 
  • Like
Reactions: BigJim55

·
Registered
Joined
·
84 Posts
One more question are you keeping your rpms up while planting?

Sent from my LGLS990 using Tapatalk
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #5 ·
You just showing low flow, or no flow. They make flow gauges and I checked mine for using a hydraulically drive snow blower. I have the high flow pump on mine. I used power beyond setup and also teed the return to also use the return svc. I found that some quick connect fitting are not rated for the flow I was putting though them. Just my two cents

Sent from my LGLS990 using Tapatalk
The vacuum works fine on its own, but when you raise the planter then you can hear the vacuum slow down until the planter has fully lifted. vacuum doesnt turn off, it just slows down to half of its pressure. so im assuming flow is taken from the vacuum to assist the planter lifting. it hadnt done that until now, so i assume something is wrong. i have 2 scv valves so i use the flow control to adjust the vacuum pressure. i never got a power beyond because i didnt need an extra valve. my vacuum return just dumps back into the sump. and if i remember correctly, we bought quick connects for motor returns that werent restricted. this setup worked at some point. not anymore, so something has to be wrong.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #6 ·
One more question are you keeping your rpms up while planting?

Sent from my LGLS990 using Tapatalk
i never got back into the tractor to test it. the mechanic had showed up and i wasnt in the tractor when the problem started. when i set all of this up, even at low rpm, the vacuum stayed on and at 10" for corn and 8" for beans, even while raising it. the owner said that the whole tractor almost stalled when all of this happened, thats how he knew something was wrong. so he lloked back and saw that the vacuum wasnt consistant while raising the planter. and he would of been in high rpm at that point.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #7 ·
could the charge pump be losing its fluid since im dumping my return from the vacuum back into the sump, instead of back into the scv? or could a load sensing spring in the bottom of each valve be bad? it baffles me that when i lost flow, swapping the valves for lift and vacuum around worked for about 45 minutes..... then same problem.
 

·
Administrator
Joined
·
21,940 Posts
Just spit-balling here. Could be a defective coupling.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #9 ·
Just spit-balling here. Could be a defective coupling.
Maybe, but that doesnt explain why the vacuum works until the planter is trying to be lifted.

i forgot to mention that the planter was previously ran by a pto pump. so the planter still has its radiator and oil filter.

im open to any suggestions though.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #10 ·
is there a main pressure sensing valve before the rear remotes???? im wondering if maybe its stuck half closed. so when the planter is trying to be lifted while vac is on, then the flow isnt there so it robs it from the vac.
 

·
Registered
Joined
·
1,104 Posts
That port is the recommended place for no pressure return. That isn't your problem. Problem may be the type of selective control valve you have. The standard valve for 6420 is the 200 series valve and they are not designed to have flow compensation when other functions are used. The optional 300 series valve is what you need. The cap on top of the valve is where you adjust your detents. DOes your valves have 2 position or 3? You need the 3 position valve to operated consistent speed for your vacuum. If you do have 300 series valves, then you may have a sticking valve or broken spring in compensator valve.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #13 ·
That port is the recommended place for no pressure return. That isn't your problem. Problem may be the type of selective control valve you have. The standard valve for 6420 is the 200 series valve and they are not designed to have flow compensation when other functions are used. The optional 300 series valve is what you need. The cap on top of the valve is where you adjust your detents. DOes your valves have 2 position or 3? You need the 3 position valve to operated consistent speed for your vacuum. If you do have 300 series valves, then you may have a sticking valve or broken spring in compensator valve.
i have the 300 series. i set it to the motor selector. but there is a possibility that the owner reached back and turned it. usually i do all the set up for him but i was gone on vacation. any possibility he turned the detent selector and thats what is making the vac slow down upon raising the planter? i throught all that 3 selector switch did was change how the detent operated.

and the sticky valve or broken spring in compensator valve sounds like an option to look at. what do you mean sticky valve. as in the valve body the planter hoses hook up too? the compensator valve sounds like something i am looking for. where is that? i am gonna research that and ask my hydraulic guy if he has looked at that spring. thanks you!!
 

·
Registered
Joined
·
84 Posts
Does the remotes have the know on top with the choice for running hydraulic motor? Is that what it is set to? When mine was first hooked up it sounded like the pump was cavatating that's when I found the problem with the return and went to the power beyond setup. And still had it happen a little so teed in an also returned into the svc also. Do you hear anything like that? A slurping sound.

Sent from my LGLS990 using Tapatalk
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #15 ·
Does the remotes have the know on top with the choice for running hydraulic motor? Is that what it is set to? When mine was first hooked up it sounded like the pump was cavatating that's when I found the problem with the return and went to the power beyond setup. And still had it happen a little so teed in an also returned into the svc also. Do you hear anything like that? A slurping sound.

Sent from my LGLS990 using Tapatalk
i dont remember hearing anything. ill have to double check.
 

·
Registered
Joined
·
84 Posts
Mine has a black know with a cylinder pic on it and a motor symbol to chose from. The motor setting lets the lever hold in the on position detected. Not sure if it has any other functionality

Sent from my LGLS990 using Tapatalk
 

·
Registered
Joined
·
84 Posts
That was supposed to read knob

Sent from my LGLS990 using Tapatalk
 

·
Registered
Joined
·
84 Posts
My return port is higher on the valve bank itself not in the pto case

Sent from my LGLS990 using Tapatalk
 

·
Registered
Joined
·
1,104 Posts
The 300 series valve should have three positions to choose from. One has a loader boom picture which has no detent. another picture is a cylinder which should have what I call a kick out detent. You use that setting when you want the detent to hold the lever until cylinder reaches the end of its stroke, then it kicks back to neutral automatically. The third setting is for constant flow such as you want for a hydraulic motor. The knob only controls the detent operation. It has no affect on hydraulic flow. Parts marked "N" in diagram is compensator valve. Remove the plug and oring from bottom of the valve. Then remove the compensator valve. The upper 4 parts of "N" should come out together. The top and bottom parts are threaded into each other. Make sure they are threaded in all the way. They have a history of unscrewing part way. I always screw them all the way apart and clean oil from threads, then apply Loctite before screwing back together. The top part has a smaller diameter land in the middle of it. You can grip it there with thin needle nose vise grips and the bottom part has a screwdriver slot. Tighten it as tight as you can get it and reinstall it.
 

Attachments

·
Registered
Joined
·
15 Posts
Discussion Starter · #20 ·
The 300 series valve should have three positions to choose from. One has a loader boom picture which has no detent. another picture is a cylinder which should have what I call a kick out detent. You use that setting when you want the detent to hold the lever until cylinder reaches the end of its stroke, then it kicks back to neutral automatically. The third setting is for constant flow such as you want for a hydraulic motor. The knob only controls the detent operation. It has no affect on hydraulic flow. Parts marked "N" in diagram is compensator valve. Remove the plug and oring from bottom of the valve. Then remove the compensator valve. The upper 4 parts of "N" should come out together. The top and bottom parts are threaded into each other. Make sure they are threaded in all the way. They have a history of unscrewing part way. I always screw them all the way apart and clean oil from threads, then apply Loctite before screwing back together. The top part has a smaller diameter land in the middle of it. You can grip it there with thin needle nose vise grips and the bottom part has a screwdriver slot. Tighten it as tight as you can get it and reinstall it.
could the compensator valve go out in both.... 45 minutes apart from each other?
 
1 - 20 of 22 Posts
Top