3-Point Hitch siromer wont lift

[dewson]

Hi recently purchased a siromer 204s tph not working steering ok any body got any ideas regards :confused2:

 

[RonMar]

When you try and lift the 3PH, does the engine sound any different, like it is being placed under load? This would indicate the system is building hydraulic pressure. This means the control valve is trying to send fluid somewhere which is causing pressure to build which is good. If the engine dosn't change sound, it could be that the valve has an internal problem and is not sending fluid where it belongs. Or the safety relief in the 3PH valve is stuck open keeping it from building any pressure. Or the seal on the 3PH piston is blown and the fluid is just flowing past the piston instead of lifting it.

If the engine DOES bog down/change sound when you try and lift the 3PH, Does the tractor have a 3PH speed regulating valve on it, usually a knob(looks like a round water faucet handle) down in front of the seat? It is used to keep heavy 3PH loads from slamming to the ground. IF that is screwed all the way in, it could be preventing any fluid from reaching the 3PH cylinder and lifting the hitch. Or if the speed reg valve is open, it could be the internal linkage in the lift is mechanically jammed.

Good Luck

 

[dewson]

When you try and lift the 3PH, does the engine sound any different, like it is being placed under load? This would indicate the system is building hydraulic pressure. This means the control valve is trying to send fluid somewhere which is causing pressure to build which is good. If the engine dosn't change sound, it could be that the valve has an internal problem and is not sending fluid where it belongs. Or the safety relief in the 3PH valve is stuck open keeping it from building any pressure. Or the seal on the 3PH piston is blown and the fluid is just flowing past the piston instead of lifting it.

If the engine DOES bog down/change sound when you try and lift the 3PH, Does the tractor have a 3PH speed regulating valve on it, usually a knob(looks like a round water faucet handle) down in front of the seat? It is used to keep heavy 3PH loads from slamming to the ground. IF that is screwed all the way in, it could be preventing any fluid from reaching the 3PH cylinder and lifting the hitch. Or if the speed reg valve is open, it could be the internal linkage in the lift is mechanically jammed.

Good Luck

Hi thanks for the reply the engine does bog down when the steering is turned, but not when tph lever is moved no flow to tph from the priority valve I suspect. The valve has been checked and cleaned maybe the pump is the problem ? . The tractor has previously done very little work but has been neglected, When the banjo is loosened at the control valve it only drips there is no pressure that you would expect very gratefull for any advice regards Dewson

 

[RonMar]

When you say valve has been checked, which valve are you refering to? Have you disassembled the diverter valve and checked that it's piston is sliding freely?

 

[dewson]

When you say valve has been checked, which valve are you refering to? Have you disassembled the diverter valve and checked that it's piston is sliding freely?

Hi yes the diverter valve has been checked piston slides without any problems, slackened two banjos on top oil leaks out slackened banjo on the rear only a few drips , oil is returning to the tank lift unit through the return pipe, pump seems to be pushing out a good pressure. tractor has 96 hours only and has sat idle for some time they purchased it new and had given up hope, somebody has looked at it previously and given up, only wish I had a diagram for the diverter valve in case its assembled wrongly or something missing that I am unaware of, thanks again for your invaluable help as I am lost for answers regards Dewson

 

[RonMar]

Well on mine, the main return flow is back thru the pipe that runs to the 3PH control valve. The only time it returns thru the other pipe is when you are operating the steering. That is why the 3PH quits working when you turn the wheel, it looses flow. Now perhaps the diverter valve is not moving fully, or more important returning fully to allow that flow down the pipe to the 3PH control valve. It also could be that the diverter is not plummed correctly. Here is a picture of the diverter on mine. It has 4 fittings, the one toward the front of the tractor(right in this pic) is the fluid input coming from the pump. There is one you cant see in this pic on the side toward the tractor. That is connected to the output line to the 3PH that is the gold metal pipe running off to the left in the pic. Then there are the two fittings on the top of the diverter. The one on the left in this pic(toward rear of tractor) is connected to the steering vane pump at the base of the steering column. The one on the right, nearest the front and closest to the inlet of the diverter is connected to the steering return line that runs down the left side of the tractor to the reservoir.

I wonder how this would act if those top 2 fittings were reversed? As I understand it, the flow is thru the diverter valve and back to the 3PH. When you turn the steering wheel, The vane pump gives the fluid a path thru that rear top fitting and the piston shifts and diverts pressure that way to power assist the steering. Now if the top ports were reversed, the fluid would always have a path thru that upper rear port, so the valve would divert and stay diverted. Not sure how the steering would react though, but the 3PH would definitely not function...



I don't know the origin of your tractor, but here is a diagram of a Jinma 284 hydraulic system FYI...

 

[dewson]

Hi checked pipes for a minute I thought you were on to something, but all connected correctly foiled again I think the next step will be to check output of the pump to see what sort of pressure its pumping cant think of anything else. thanks again let you know how I get on regards Dewson

 

[erj]

Do you have the speed regulator valve that Ron mentioned in his first post? If so, try screwing it all the way down then see if there is any change in engine sound when engaging 3ph.
RonJ

 

[dewson]

Do you have the speed regulator valve that Ron mentioned in his first post? If so, try screwing it all the way down then see if there is any change in engine sound when engaging 3ph.
RonJ

Hi yes speed regulator is fitted and in or out makes no difference, oil does not flow to the back for some reason makes me think that the pump is not delivering enough pressure or its flowing were it shouldn't ? the return possibly, all pipes appear to be connected correctly and the steering works fine, also stripped diverter valve plunger moves freely going to check the pressure next thanks for the help regards Dewson

 

[RonMar]

Well IT could be the diverter not returning to main position to feed 3PH, or the rotary vane pump/steering assembly is leaking past, allowing flow out of the diverter which keeps it diverted to the priority/steering port.

One way to break this tie, short of swapping one out, might be to plug that priority port, and deny flow to steering the same way the steering box should when you are not turning the wheel. If working properly this should make the diverter valve flow fluid to the 3PH. You could plug the port to the steering fairly easilly with a metric bolt put in place of the hollow banjo bolt. Doing this would have one of two outcomes
1. The diverter will function as designed and send fluid to the 3PH, indicating the steering vane pump/valve is the issue.
2. The diverter valve will stay stuck in divert. Since this port is now blocked for testing, the pressure will build till it exceeds the relief pressure in the diverter and fluid will flow out that 4th diverter port . The 3PH will continue not to function. You may hear the added load on the engine, but it should only build as much pressure as the system does when you turn the steering out to one steering limit or the other. On mine it builds about 500 PSI. To confirm that the diverter relief function is working properly before you block the port, you can start the engine and while idling, turn the steering all the way to a stop and see how the engine responds. You should hear it load down a bit when the steering reaches an end stop. IF it stalls the engine at idle, it may not be relieving properly, and may not be advisable to do the blocked diverter port test as without a relief, would completely dead head the pump with a malfunctioning diverter valve.

 

[dewson]

Well IT could be the diverter not returning to main position to feed 3PH, or the rotary vane pump/steering assembly is leaking past, allowing flow out of the diverter which keeps it diverted to the priority/steering port.

One way to break this tie, short of swapping one out, might be to plug that priority port, and deny flow to steering the same way the steering box should when you are not turning the wheel. If working properly this should make the diverter valve flow fluid to the 3PH. You could plug the port to the steering fairly easilly with a metric bolt put in place of the hollow banjo bolt. Doing this would have one of two outcomes
1. The diverter will function as designed and send fluid to the 3PH, indicating the steering vane pump/valve is the issue.
2. The diverter valve will stay stuck in divert. Since this port is now blocked for testing, the pressure will build till it exceeds the relief pressure in the diverter and fluid will flow out that 4th diverter port . The 3PH will continue not to function. You may hear the added load on the engine, but it should only build as much pressure as the system does when you turn the steering out to one steering limit or the other. On mine it builds about 500 PSI. To confirm that the diverter relief function is working properly before you block the port, you can start the engine and while idling, turn the steering all the way to a stop and see how the engine responds. You should hear it load down a bit when the steering reaches an end stop. IF it stalls the engine at idle, it may not be relieving properly, and may not be advisable to do the blocked diverter port test as without a relief, would completely dead head the pump with a malfunctioning diverter valve.

Hi thanks again for the reply maybe there is a fault with either the steering ram or the column because as you say with yours the flow doesn't cut off until you steer , with mine the flow is returning to the reservoir through the pipe on the left without touching the steering wheel but it appears to steer fine to me, looks like steering circuit is continually flowing pumping. On the hydraulic cover under the seat I removed a small cover with three bolts and can see the oil returning with engine running and nobody touching the wheel . Could be the seals in the steering ram bypassing ? thanks again for your help Dewson

 

[RonMar]

Fluid should only be able to get to the ram when you turn the wheel. If fluid was headed to the ram it would be pushing the wheels left or right. If the ram was leaking past, the wheels would not turn or turn sluggishly when you turned the wheel.

In thinking about this some more, I went out and pulled the output line on my steering valve/rotary vane pump to check, and surprisingly(well not really when I think about it) there is fluid flowing out of it whenever the engine is running. So some assumptions I was making earlier are incorrect. And if I had thought about it a little more, it probably would have come to me then. You need flow to control flow, so there is always some flow thru the steering valve. It is when the steering is operated, that more flow is demanded from the system, and the diverter shifts more flow to the steering, denying flow to the 3PH in the process. SO either the diverter is faulty, or the pilot flow thru the steering is excessive, causing the diverter to remain diverted to meet this demand. After this revelation, I am thinking the only way to troubleshoot this further is to swap out a part. My first choice would be the diverter as it is less expensive and easier to access and swap. Here is some additional info on the diverter from Johns Jinma website.
DiverterValve

 

[dewson]

Fluid should only be able to get to the ram when you turn the wheel. If fluid was headed to the ram it would be pushing the wheels left or right. If the ram was leaking past, the wheels would not turn or turn sluggishly when you turned the wheel.

In thinking about this some more, I went out and pulled the output line on my steering valve/rotary vane pump to check, and surprisingly(well not really when I think about it) there is fluid flowing out of it whenever the engine is running. So some assumptions I was making earlier are incorrect. And if I had thought about it a little more, it probably would have come to me then. You need flow to control flow, so there is always some flow thru the steering valve. It is when the steering is operated, that more flow is demanded from the system, and the diverter shifts more flow to the steering, denying flow to the 3PH in the process. SO either the diverter is faulty, or the pilot flow thru the steering is excessive, causing the diverter to remain diverted to meet this demand. After this revelation, I am thinking the only way to troubleshoot this further is to swap out a part. My first choice would be the diverter as it is less expensive and easier to access and swap. Here is some additional info on the diverter from Johns Jinma website.
DiverterValve

Hi Ron at last the hydraulics are lifting, the pump must have had enough pressure to work the steering but not enough to open the diverter, I took a chance and changed the pump and filter and now my problems are solved, thanks for your help and support regards Dewson