I just purchased a 2002 Jinma 224 tractor. The three point lift goes up and down without any weight on it, but if I put weight on it, it won't raise. The engine does not react to moving the lift like it does when using the front loader. What am I not doing? Also, what are you using for fluid in the hydraulics?
RonMar
Elite Member
How much weight are you trying to lift(hopefully not more than what the 3PH on that tractor is rated for)? Could be that the seals in the 3PH cylinder are shot. When you put load on the lift arms, the fluid flows around the piston instead of pushing it. This is a relatively simple fix and not all that uncommon if the lift control linkage is setup incorrectly and lets the 3PH lift piston extend too far which will damage the piston seal. It could also be a problem with the 3PH control valve. Or it could be as simple as the safety relief valve on the 3PH control valve is stuck open or not set properly. Here is a way you might be able to tell which is the problem.
1. Attach an impliment that you know it won't lift IE: try and lift the same "weight" that it wouldn't lift before.
2. Useing a floor jack, help the tractor to lift the weight(tractor running, 3PH control lever in the "raise" position and jack up the load with the jack.
3. Located on the front of the 3PH lift box right below the front of the seat should be a round valve handle(looks like a garden hose faucet). This valve is used to control the lowering speed of the 3PH so it dosn't let a heavy impliment freefall when the control lever is placed in the lower position. With the weight raised fully, turn this valve fully clockwise(close it). Depending on how much this valve has been used, it may be difficult to turn(rust on threads) and may need to be removed and cleaned up. There is a small screw on the front of the housing that the valve is screwed into. This screw limits the travel of the valve and will have to be removed if you need to remove the valve for cleaning. When fully closed, this valve should hydraulically lock the cylinder in the raised position.
4. Lower the jack, If the impliment stays in the air, then the seals on the piston are OK and the problem lies in the 3PH control valve or the safety valve. If the cylinder now holds the load, You will probably have to jack up the load to allow you to open the valve as when closed with a load on the 3PH, you are fighting the hydraulic pressure created by the weight to open the valve. I can't open mine on my 284 when I set it too tight and have to lift the impliment with a jack to relieve the pressure.
As for fluid, AW32 is a good all around choice for the hydraulics on these machines.
1. Attach an impliment that you know it won't lift IE: try and lift the same "weight" that it wouldn't lift before.
2. Useing a floor jack, help the tractor to lift the weight(tractor running, 3PH control lever in the "raise" position and jack up the load with the jack.
3. Located on the front of the 3PH lift box right below the front of the seat should be a round valve handle(looks like a garden hose faucet). This valve is used to control the lowering speed of the 3PH so it dosn't let a heavy impliment freefall when the control lever is placed in the lower position. With the weight raised fully, turn this valve fully clockwise(close it). Depending on how much this valve has been used, it may be difficult to turn(rust on threads) and may need to be removed and cleaned up. There is a small screw on the front of the housing that the valve is screwed into. This screw limits the travel of the valve and will have to be removed if you need to remove the valve for cleaning. When fully closed, this valve should hydraulically lock the cylinder in the raised position.
4. Lower the jack, If the impliment stays in the air, then the seals on the piston are OK and the problem lies in the 3PH control valve or the safety valve. If the cylinder now holds the load, You will probably have to jack up the load to allow you to open the valve as when closed with a load on the 3PH, you are fighting the hydraulic pressure created by the weight to open the valve. I can't open mine on my 284 when I set it too tight and have to lift the impliment with a jack to relieve the pressure.
As for fluid, AW32 is a good all around choice for the hydraulics on these machines.
Affordable
Advertiser, Platinum Member
Sounds like you need to rebuild the 3-point lift, we sell a rebuild kit for it. Not a real big job if you have some mechanical ability.Send me a PM if you want some pricing or information
Tommy
Affordable Tractor Sales
Tommy
Affordable Tractor Sales
I appreciate the information. It ahs been helpful. I am only lifing 200 lbs. and the lift will hold with the lowering valve closed. I unhooked the front loader last night to see if that would make a difference. The tractor would not start. THe hight pressure hose of the front loader pulsated with every turn o the engine. The pressure just backed up in the pump. You mentioned a pressure releif valve. Are there seperate valves for the front end loader and the 3 point lift? If so where are they located, and how would I fix one that is stuck? Also is there a hydraulic fluid filter? Where does the hydraulic pump draw fluid from?
RonMar
Elite Member
If you unhooked the loader, you need to connect the tractor quick connects together so there is flow from the pump back to the 3PH control valve. If you just disconnected the lines, this deadheads the pump and can break the pump(blow seals, crack pump case) if you try to run it this way. Quick connect fittings being inadvertantly opened while the engine is running have been the cause of many pump failures. One suggestion is to place large ty-wraps or zip-ties around the QC body to keep them from accidentally being opened.
I wouldn't think the front end loader valve has anything to do with the 3PH problem as the fluid basically just flows through it unless you are performing some work with the loader. Since the 3PH holds weight with the lowering/speed regulating valve closed, there is most likley nothing wrong with the lift cylinder seals. The valve itself is pretty simple. Fluid enters from the pump(or FEL valve assembly if so equipped) and when in the "neutral" or "lower" position flows right into the resovoir. When you move the control lever to the "Raise position, this flow from the pump is diverted to the 3PH cylinder input, pressure builds and the 3PH raises. When you return the lever to "neutral", the fluid in the cylinder is trapped there. When the lever is shifted to "lower" the fluid in the cylinder is released back to the resovoir along with the flow from the pump and the 3PH lowers. Between the control valve and the cylinder is a pressure reliefe valve and the speed regulating valve. IF the pressure reliefe valve is leaking, the fluid will take that easier path back to the resovoir instead of lifting the 3PH load. This valve is located on the top front of the 3PH loader control valve part #s 1-7 on the linked picture at John's Jinma site.
http://johnstractor.homestead.com/files/HydValve.jpg
As the pic shows, the valve is located under a square headed pipe plug and consists of a spring, some shim washers and a valve that seals a hole. If the pressure below the valve exceeds the spring pressure then the valve opens and dumps fluid back to the resovoir. This valve also helps protect the 3PH from shock loads that occur when bouncing a heavy impliment over rough terrain.
The only filtration is a brass screen strainer located on the suction line inside the resovoir/lift box usually accessed from the top of the resovoir. The 3PH lift cylinder is also inside the resovoir.
With a front end loader there will be 2 safety valves in your system. One is in the loader valve. If you attempt to lift too much weight with the FEL, that safety valve will open and allow the fluid to bypass the overload and continue on to the resovoir via the 3PH control valve. The second safety is in the 3PH loader control as described above. I had a problem with my 3PH safety valve. The safety was set too high. I had the 3PH speed regulating valve closed too tight placing a lot of restriction on the fluid as it entered the 3PH cylinder. Every time I lifted my brushhog, I sent the pressure in the system over 3000 PSI. The first failure I noticed was at the "O" rings on the loader valve. They started dumping fluid on my right foot every time I lifted the brushhog. This excessive pressure was also felt back at the dump trailer quick connect that my 284 came with. It bent the cage assembly that holds the checkball and the QC fitting started to leak whenever I lifted the brushhog.
I wouldn't think the front end loader valve has anything to do with the 3PH problem as the fluid basically just flows through it unless you are performing some work with the loader. Since the 3PH holds weight with the lowering/speed regulating valve closed, there is most likley nothing wrong with the lift cylinder seals. The valve itself is pretty simple. Fluid enters from the pump(or FEL valve assembly if so equipped) and when in the "neutral" or "lower" position flows right into the resovoir. When you move the control lever to the "Raise position, this flow from the pump is diverted to the 3PH cylinder input, pressure builds and the 3PH raises. When you return the lever to "neutral", the fluid in the cylinder is trapped there. When the lever is shifted to "lower" the fluid in the cylinder is released back to the resovoir along with the flow from the pump and the 3PH lowers. Between the control valve and the cylinder is a pressure reliefe valve and the speed regulating valve. IF the pressure reliefe valve is leaking, the fluid will take that easier path back to the resovoir instead of lifting the 3PH load. This valve is located on the top front of the 3PH loader control valve part #s 1-7 on the linked picture at John's Jinma site.
http://johnstractor.homestead.com/files/HydValve.jpg
As the pic shows, the valve is located under a square headed pipe plug and consists of a spring, some shim washers and a valve that seals a hole. If the pressure below the valve exceeds the spring pressure then the valve opens and dumps fluid back to the resovoir. This valve also helps protect the 3PH from shock loads that occur when bouncing a heavy impliment over rough terrain.
The only filtration is a brass screen strainer located on the suction line inside the resovoir/lift box usually accessed from the top of the resovoir. The 3PH lift cylinder is also inside the resovoir.
With a front end loader there will be 2 safety valves in your system. One is in the loader valve. If you attempt to lift too much weight with the FEL, that safety valve will open and allow the fluid to bypass the overload and continue on to the resovoir via the 3PH control valve. The second safety is in the 3PH loader control as described above. I had a problem with my 3PH safety valve. The safety was set too high. I had the 3PH speed regulating valve closed too tight placing a lot of restriction on the fluid as it entered the 3PH cylinder. Every time I lifted my brushhog, I sent the pressure in the system over 3000 PSI. The first failure I noticed was at the "O" rings on the loader valve. They started dumping fluid on my right foot every time I lifted the brushhog. This excessive pressure was also felt back at the dump trailer quick connect that my 284 came with. It bent the cage assembly that holds the checkball and the QC fitting started to leak whenever I lifted the brushhog.
Ron, Thanks again. I did remove the pressure relief valve you described. The valve consisted of the spring, washers and the pointed piece and the metal seat. This valve appeared to be free and working. Is the hydraulic fluid reservoir under the 3 point lift, or is there hydraulic fluid stored in other locations? Do you have any other suggestions on why the lift won't lift any weight, but will hold pressure. The lowering adjustment valve was difficult to move and needed to have the threads lubricated. Thanks for your help!
Affordable
Advertiser, Platinum Member
I posted earlier in this thread that you will need to rebuild your 3-point lift.If your steering is fine it is prob. fluid leaking by the O-rings.
Tommy
Affordable Tractor Sales
Tommy
Affordable Tractor Sales
SPIKER
Elite Member
Cheif:
Lucky you didn't BLOW up the pump when you tried to start the tractor with the Hydraulic lines disconnected the pumps on these require to flow fluid 100% of time and when a Front End Loader (FEL) is installed they are often the 1st item inline after the pressure side of the pump, hence when the FEL line gets disconnected there is no where for the pump to push the fluiid and it blows up the easiest part, (Usually pump end seals, housing and or the back of the pump.) now the line could also blow but usually the lines hold up while the pump blows.
now for the 3pt lift.. there could be 2 things that could cause the lift to not raise weight, one is the valve the other is the relife. since you already noted the weight staied UP when the drop speed valve was clsoed then the lift cylinder seals are probably OK, (though this may not be the case as I'm not sure where the drop speed valve is in relation to the cylinder on these.) anyhwo the lift valve probably is not the cause as these are setup withoug seals and are metal to metal spools on these. the relife may look OK but may be set too LOW of pressure. they are adjustable so I would try there first..
post back with results and we can all try & help.
mark M
Lucky you didn't BLOW up the pump when you tried to start the tractor with the Hydraulic lines disconnected the pumps on these require to flow fluid 100% of time and when a Front End Loader (FEL) is installed they are often the 1st item inline after the pressure side of the pump, hence when the FEL line gets disconnected there is no where for the pump to push the fluiid and it blows up the easiest part, (Usually pump end seals, housing and or the back of the pump.) now the line could also blow but usually the lines hold up while the pump blows.
now for the 3pt lift.. there could be 2 things that could cause the lift to not raise weight, one is the valve the other is the relife. since you already noted the weight staied UP when the drop speed valve was clsoed then the lift cylinder seals are probably OK, (though this may not be the case as I'm not sure where the drop speed valve is in relation to the cylinder on these.) anyhwo the lift valve probably is not the cause as these are setup withoug seals and are metal to metal spools on these. the relife may look OK but may be set too LOW of pressure. they are adjustable so I would try there first..
post back with results and we can all try & help.
mark M
RonMar
Elite Member
</font><font color="blue" class="small">( Ron, Thanks again. I did remove the pressure relief valve you described. The valve consisted of the spring, washers and the pointed piece and the metal seat. This valve appeared to be free and working. Is the hydraulic fluid reservoir under the 3 point lift, or is there hydraulic fluid stored in other locations? Do you have any other suggestions on why the lift won't lift any weight, but will hold pressure. The lowering adjustment valve was difficult to move and needed to have the threads lubricated. Thanks for your help! )</font>
The fluid resovoir is inside the 3PH lift box case, Part #55 in the linked picture.
http://johnstractor.homestead.com/files/HydPowerLift.jpg
The 3PH lift cylinder, pushrod and linkages are submerged in the stored fluid that nearly fills the case.
As Spiker said, the 3PH control valve is pretty simple with only a single moveing spool shaft and no seals. Since it holds weight with the speed regulating valve closed, the piston seals are OK. You can fully confirm this by seeing that it holds weight with the speed regulator closed with the 3PH at different heights(piston at different locations along it's cylinder). I would think this to be unlikly that the piston would seal with the 3PH at full height but not seal down low.
With piston seals OK, That leaves the lift valve or the safety. You inspected the Safety but as Spiker mentioned, it is a simple test to add some additional shim washers on top of the spring to raise the ammount of force required from the fluid to push open the valve. The valve on my 284 had 4 shim washers in it when delivered. This was a few too many in my case. Also make sure the top plug is screwed in all the way as this will also effect the spring pre-load.
If this makes no change, I would reccomend disassembly and inspection of the 3PH lift control valve. There may be a crack in the casting allowing fluid to bypass the work of lifting the 3PH when loaded.
The fluid resovoir is inside the 3PH lift box case, Part #55 in the linked picture.
http://johnstractor.homestead.com/files/HydPowerLift.jpg
The 3PH lift cylinder, pushrod and linkages are submerged in the stored fluid that nearly fills the case.
As Spiker said, the 3PH control valve is pretty simple with only a single moveing spool shaft and no seals. Since it holds weight with the speed regulating valve closed, the piston seals are OK. You can fully confirm this by seeing that it holds weight with the speed regulator closed with the 3PH at different heights(piston at different locations along it's cylinder). I would think this to be unlikly that the piston would seal with the 3PH at full height but not seal down low.
With piston seals OK, That leaves the lift valve or the safety. You inspected the Safety but as Spiker mentioned, it is a simple test to add some additional shim washers on top of the spring to raise the ammount of force required from the fluid to push open the valve. The valve on my 284 had 4 shim washers in it when delivered. This was a few too many in my case. Also make sure the top plug is screwed in all the way as this will also effect the spring pre-load.
If this makes no change, I would reccomend disassembly and inspection of the 3PH lift control valve. There may be a crack in the casting allowing fluid to bypass the work of lifting the 3PH when loaded.
Ron and others,
I appreciate all the help. I have learned a lot about this tractor. I believe I found the problem. I found that the previous owner, who purchased the tractor new, never or hardly ever used the 3 point. I just continued to run the hitch up and down last night thinking that a valve may by sluggish or stuck. After doing this for 15 or 20 minutes, I stood on the hitch and worked the lever. It worked just fine. I will continue to test and work it, but I think the problem was just lack of being used and worked. Again, thanks for all of you guys help. This is a great site.
I appreciate all the help. I have learned a lot about this tractor. I believe I found the problem. I found that the previous owner, who purchased the tractor new, never or hardly ever used the 3 point. I just continued to run the hitch up and down last night thinking that a valve may by sluggish or stuck. After doing this for 15 or 20 minutes, I stood on the hitch and worked the lever. It worked just fine. I will continue to test and work it, but I think the problem was just lack of being used and worked. Again, thanks for all of you guys help. This is a great site.