Jinma 284 - 3 pt lift not working

   / Jinma 284 - 3 pt lift not working #1  

ctusdenny

Member
Joined
May 25, 2014
Messages
35
Location
Cashmere, wa
Tractor
2005 Jinma 284
Hi

Originally posted this in the general troubleshooting forum. Figured I'd repost here to see if I get more specific replies...

I recently took possession of a 2005 Jinma 285 w/ FEL. It came with a piece of property I recently purchased. When handing it over, the previous owner indicated that the rear 3 pt. lift system wasn't working. Here is what he said has been done so far to correct the issue:

"It appears the control valve on the front end of the hydraulic reservoir is not receiving fluid from the power steering loop. I've pulled the oft valve and the PTO piston apart and that all looks good. The hydraulic pump has also been replaced and seems good (it will lift the front end loader, but not the rear lift)."

So...the FEL works, and the PTO piston has been checked, and a new pump installed. I'm wondering if anyone has run into this same issue? Or perhaps some suggestions where to start looking/ testing next.

I'm just getting familiar with the tractor, so any advice would be great.

Thank you. Denny
 
   / Jinma 284 - 3 pt lift not working #2  
Denny Under the seat (between your legs) there is a valve. That valve controls fluid into/out of the lift valve on the side of the case (under right side of seat)

There is a Allen head set screw on the valves face (one under the seat between your legs) and a Knob on top. The KNOB controls fluid to the lift arms, the set screw HOLDS it in place has to be loosened up then you can turn the valve letting fluid flow into the lift arm cyl. It may be there is junk in that valve or that someone screwed it all way down (when you do that all the fluid goes to the 3pt QD on the back of the tractor for lifting say a plow or Dump trailer cylinder.) It also will control how FAST the 3pt raises/lowers by restricting the fluid into or out of it.

then there is a 3pt relieve valve which protects the system from blowing out the lift arm's seals if you put too much weight on the 3pt. That is a poppet style valve controlled by a spring pushing a cone into a seat. It works by pressure building on the point of the cone, when pressure on the cone is higher than spring pressure the cone is pushed up and fluid bypasses back to tank. Junk can sometimes stick the cone OPEN so no pressure can build. Other issue is the spring could break and then no pressure to keep the cone seated (no pressure to raise lift.) Not positive on the 05 model but I think that is on the side of the 3pt lift box valve (bottom half facing forward & looks like a cap with a couple lock nuts on it.) It is not complicated but need to be careful & be able to attach a gauge to set pressure back correctly if you disassemble it. Counting turns of the screw might work IF it is JUNK stuck in it but a broken spring you need to know the pressure to keep from damaging the lift assy.

Mark
 
   / Jinma 284 - 3 pt lift not working
  • Thread Starter
#3  
Denny Under the seat (between your legs) there is a valve. That valve controls fluid into/out of the lift valve on the side of the case (under right side of seat)

There is a Allen head set screw on the valves face (one under the seat between your legs) and a Knob on top. The KNOB controls fluid to the lift arms, the set screw HOLDS it in place has to be loosened up then you can turn the valve letting fluid flow into the lift arm cyl. It may be there is junk in that valve or that someone screwed it all way down (when you do that all the fluid goes to the 3pt QD on the back of the tractor for lifting say a plow or Dump trailer cylinder.) It also will control how FAST the 3pt raises/lowers by restricting the fluid into or out of it.

then there is a 3pt relieve valve which protects the system from blowing out the lift arm's seals if you put too much weight on the 3pt. That is a poppet style valve controlled by a spring pushing a cone into a seat. It works by pressure building on the point of the cone, when pressure on the cone is higher than spring pressure the cone is pushed up and fluid bypasses back to tank. Junk can sometimes stick the cone OPEN so no pressure can build. Other issue is the spring could break and then no pressure to keep the cone seated (no pressure to raise lift.) Not positive on the 05 model but I think that is on the side of the 3pt lift box valve (bottom half facing forward & looks like a cap with a couple lock nuts on it.) It is not complicated but need to be careful & be able to attach a gauge to set pressure back correctly if you disassemble it. Counting turns of the screw might work IF it is JUNK stuck in it but a broken spring you need to know the pressure to keep from damaging the lift assy.

Mark

thanks, Mark. good info for sure. I'll poke around more and see if I can located any blockages. This helps a bunch to get me started at least.
 
   / Jinma 284 - 3 pt lift not working #4  
Like spiker said, make sure that valve down in front of the seat is not screwed down all the way. It has a round handle like a garden hose faucett. The setscrew he mentioned only needs to be removed to completely unscrew and remove the main valve shaft. It screws down into a notch in the main shaft to keep you from accidently unscrewing it too far.

I have an 05 Jinma, and the 3PH relief valve is located on top of the 3PH control valve block. It is a square headed pipe plug. The relief point is set by the number of stacked washers on top of the spring held down by the plug. You can take it out and put it back without a gauge as the plug screws down fully. But it is a good idea to verify the 3PH relief pressure. Mine was way too high from the factory...

If yours has the female quick connect comming off the 3PH valve, checking the 3PH relief pressure is no more difficult than screwing a 0-5000PSI pressure gauge into a male quick connect and plugging it into that rear QC fitting. Then you screw that control valve in front of the seat all the way in which sends all the fluid to the rear QC, which causes a deadhead and forces the relief valve open. The pressure read on the QC port is the relief pressure.

As to your problem, if the control valve in front of the seat is open and the lift dosn't start operating, the fluid must be going somewhere. Either it is still bypassign thru the valve into the reservoir, it is going thru the safety relief, or it is going into the cylinder and past a blown piston seal. A mechanics stethescope may help here. If you listen on the block in front of the piston down in front of the seat where that regulating valve is located , you may be able to hear fluid "wooshing" into the cylinder when the 3PH is commanded up(bad piston seal). or you may hear it on the 3PH control valve either thru the relief, or the valve internals are not even trying to divert the fluid to the cylinder. It is a rack and pinion affair thet moves the valve body. Here is a diagram of the valve from John's Jinma website(great reference info there:))
http://www.johnsjinma.com/files/HydValve.jpg
 
   / Jinma 284 - 3 pt lift not working
  • Thread Starter
#5  
Like spiker said, make sure that valve down in front of the seat is not screwed down all the way. It has a round handle like a garden hose faucett. The setscrew he mentioned only needs to be removed to completely unscrew and remove the main valve shaft. It screws down into a notch in the main shaft to keep you from accidently unscrewing it too far.

I have an 05 Jinma, and the 3PH relief valve is located on top of the 3PH control valve block. It is a square headed pipe plug. The relief point is set by the number of stacked washers on top of the spring held down by the plug. You can take it out and put it back without a gauge as the plug screws down fully. But it is a good idea to verify the 3PH relief pressure. Mine was way too high from the factory...

If yours has the female quick connect comming off the 3PH valve, checking the 3PH relief pressure is no more difficult than screwing a 0-5000PSI pressure gauge into a male quick connect and plugging it into that rear QC fitting. Then you screw that control valve in front of the seat all the way in which sends all the fluid to the rear QC, which causes a deadhead and forces the relief valve open. The pressure read on the QC port is the relief pressure.

As to your problem, if the control valve in front of the seat is open and the lift dosn't start operating, the fluid must be going somewhere. Either it is still bypassign thru the valve into the reservoir, it is going thru the safety relief, or it is going into the cylinder and past a blown piston seal. A mechanics stethescope may help here. If you listen on the block in front of the piston down in front of the seat where that regulating valve is located , you may be able to hear fluid "wooshing" into the cylinder when the 3PH is commanded up(bad piston seal). or you may hear it on the 3PH control valve either thru the relief, or the valve internals are not even trying to divert the fluid to the cylinder. It is a rack and pinion affair thet moves the valve body. Here is a diagram of the valve from John's Jinma website(great reference info there:))
http://www.johnsjinma.com/files/HydValve.jpg

Unbelievable! Thank you so much, Ron. That gives me a bunch to go on for sure.
 
   / Jinma 284 - 3 pt lift not working #6  
Im having a very similar problem. Just got myself a 224 with a FEL. Power steering, FEL, all the other hydro works fine. But the rear blade falls in about 30 seconds after you have it up. Mine may be a throttle related issue, as my throttle is all messed up so its hard to keep above idle. But even at idle, it shouldnt be falling. I have to mess with the knob under the seat first, and second see if my seals are shot.
 
   / Jinma 284 - 3 pt lift not working #7  
If it is falling all by itself without you shifting the handle to the lower position, most likley it is the piston seals in the lift cylinder.
 
   / Jinma 284 - 3 pt lift not working
  • Thread Starter
#8  
Update:

I finally found some time today to check into my 3 pt. lift issue. Thanks to Ron and Spiker I had a lot to go on. The adjustment of the valve under the front of the seat helped quite a bit. It had been turned nearly closed, so I opened it a few turns and the lift came back to life. There is something strange, however. When I first start the tractor from being cold, the lift barely creeps up (goes down no problem). But really slow upward even with the front valve opened almost full.

Seems like after about 10-15 mintues, it will start working better, but not great. Like I say, even with the vavle opened almost completely, the lift raiser "really" slow. I don't expect it to be fast, but this is noticably slow. The oil being used is #303 from O'Reilleys, and was just replaced a month ago by the previous owner.

Now onto what I found elsewhere:

The body that the "vavle" is threded into under the front of the seat has a threaded plug on the lower right side. It's located directly under a banjo fitting that leads back to the right side auxilary quick-connect on the rear of the tractor. There is a decent leak as I don't belive the plug was tightened correctly. The problem is I cant get a tool on it in order to snug it up. That banjo fitting blocks getting a socket on the head, and there is no way to get a wrench on it and turn with any leverage.

Questions:

1. Is there a snappy way to tighten that plug without removing anything, or losing oil? (maybe a trick someone has used?)

2. If I have to remove the banjo fitting, I'll assume that will drain a lot of fluid? It's the only way I can see tightening this plug, so I may just have to go this route.

3. If I drain the system (or what comes out when I remove the banjo fitting), is there a proper way to bleed the system once everything is back together? I'll assume it needs bleeding regardless of whether a little or a lot comes out when I remove the fitting.

4. On the subject of the hydraulic system: I am assuming that the drain for the entire system is that banjo fitting on the left side of the tank? (not the same banjo fitting I'm referring to above).

Thanks. Denny
 
   / Jinma 284 - 3 pt lift not working #9  
Update:

I finally found some time today to check into my 3 pt. lift issue. Thanks to Ron and Spiker I had a lot to go on. The adjustment of the valve under the front of the seat helped quite a bit. It had been turned nearly closed, so I opened it a few turns and the lift came back to life. There is something strange, however. When I first start the tractor from being cold, the lift barely creeps up (goes down no problem). But really slow upward even with the front valve opened almost full.

Seems like after about 10-15 mintues, it will start working better, but not great. Like I say, even with the vavle opened almost completely, the lift raiser "really" slow. I don't expect it to be fast, but this is noticably slow. The oil being used is #303 from O'Reilleys, and was just replaced a month ago by the previous owner.

Now onto what I found elsewhere:

The body that the "vavle" is threded into under the front of the seat has a threaded plug on the lower right side. It's located directly under a banjo fitting that leads back to the right side auxilary quick-connect on the rear of the tractor. There is a decent leak as I don't belive the plug was tightened correctly. The problem is I cant get a tool on it in order to snug it up. That banjo fitting blocks getting a socket on the head, and there is no way to get a wrench on it and turn with any leverage.

Questions:

1. Is there a snappy way to tighten that plug without removing anything, or losing oil? (maybe a trick someone has used?)

2. If I have to remove the banjo fitting, I'll assume that will drain a lot of fluid? It's the only way I can see tightening this plug, so I may just have to go this route.

3. If I drain the system (or what comes out when I remove the banjo fitting), is there a proper way to bleed the system once everything is back together? I'll assume it needs bleeding regardless of whether a little or a lot comes out when I remove the fitting.

4. On the subject of the hydraulic system: I am assuming that the drain for the entire system is that banjo fitting on the left side of the tank? (not the same banjo fitting I'm referring to above).

Thanks. Denny


#3 question: The system is open, so its self bleeding to the best of my knowledge. All you need to do is link to the two quick disconnects from the loader if you have them. If you dont have a loader, theyre probably already linked.

Check out cJax's thread here for a great guide on how to do a flush

http://www.mytractorforum.com/showthread.php?t=83100
 
   / Jinma 284 - 3 pt lift not working #10  
Denny, I am assuming #303 is a type of Universal Tractor Fluid or UTF? The system operating better when it warms up is a clue that the hydraulic fluid is too thick. UTF is too thick for this type hydraulic system. You need some simple AW-32 hydraulic fluid for this system to operate at it's best.

IF you look closely at the back of the lift box, at the toplink structure which is bolted to the back of the lift box, you may see something unusual if you look closely in the lower left corner. Disguised like one of the toplink plate mounting bolts is the hydraulic reservoir drain. It may even have a dab of red paint on it, which they do on many of the drains and fills to help you identify them from the factory... Inthe case of the hydraulic sump it helps to have the tractor parked with the front uphill(and wheels blocked) to assist in draining all the fluid out.

Got no help with tightening the leaking plug, other than you can pull off the banjo fitting when you drain the sump to changeout the UTF:)

DId you go ahead and remove that setscrew and the speed regulating valve completely to examine it? IF not, it is probably hiding one last secret. The pointed tip of the valve is pinned to the end of the threaded shaft with a slot so that tip can move up and down. Installed the tip hangs down at the end of the slot. When you lift the 3PH, fluid flows up against the tip, pushing it out of the way so you can get full flow to lift. When you lower the 3PH, the tip, now down in the way, restricts the exit of the fluid helping to keep a heavy impliment from slamming down. If it is screwed in a little too far, it will allow the impliment to raise, then act like a check valve and keep the impliment from lowering. Since it is now locked with hydraulic pressure, you cannot then unscrew the adjuster. The fix is to back the impliment up onto a hill or jack it up to take the weight off of the lift, and the hydraulic pressure off of the speed reg valve allowing you to unscrew it...
 
 
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