Total hydraulic Loss

[NorTracNY]

I have a Jinma 254. I was just finishing up moving some compost and realized I loss hydraulics. Even the 3pt hitch was not responsive. I looked around and found no leaks, no hoses blown, and there was still fluid. I had been using the bucket for the last hour. I'm sure this is an easy problem, but I'm pretty clueless on hydraulics.

Can anyone help me diagnose this? Referencing the part numbers or pictures would really be appreciated.

 

[timinsanborn]

does your power steering still work? if it does, then i`d suspect the priorty valve.
if no power steering and no loader /3 point. then i`d start with the basics. 1, fluid level. 2, check suction strainer in lift box under seat. 3, inspect suction line and fittings make sure all is tight and no cracks or breaks.4, then i`d suspect the pump or pump drive. i`d probably disconnect the pump output hose and put(secure) it in a bucket and briefly crank/start engine.if pump is working hydraulic fluid will shoot out. if little-no fluid comes out .then i would pull the pump and inspect.
i`m not a professional mechanic, this is what i would do if i had this problem, along with scratching my head!
i`m sure others will post more or other things to do and check.

 

[greg_g]

Pull the engine dipstick, see if the level is higher than you would normally expect

//greg//

 

[SPIKER]

check the QDs for the FEL. other things to look for leaking line or blown seal on the pump that would fill crank case up with HYD fluid most of the time. The HYD system is pretty simple so not a lot can go wrong.

Mark

 

[Egon]

Where is the pump and does it have output flow/pressure?

 

[rdbigfarmboy]

Its a small reservoir and very easy to loose prime to the pump. Loose the pressure (small) line going from pump to lift under seat. Fill reservoir with oil start engine you will get a pressure spray of oil out the loosened pressure line. tighten it and go.
The reservoir is a bit small when working with fel and on hilly terrain.

 

[NorTracNY]

does your power steering still work? if it does, then i`d suspect the priorty valve.
if no power steering and no loader /3 point. then i`d start with the basics. 1, fluid level. 2, check suction strainer in lift box under seat. 3, inspect suction line and fittings make sure all is tight and no cracks or breaks.4, then i`d suspect the pump or pump drive. i`d probably disconnect the pump output hose and put(secure) it in a bucket and briefly crank/start engine.if pump is working hydraulic fluid will shoot out. if little-no fluid comes out .then i would pull the pump and inspect.
i`m not a professional mechanic, this is what i would do if i had this problem, along with scratching my head!
i`m sure others will post more or other things to do and check.

OK, thank you all for the responses. I've examined it some more and learned to identify a few of the items from the manual.

There is no power steering, it was a tough turn backing it into a nearby shelter with the bucket dragging.
1) I checked the fluid level and it appears normal. There is about a 1/4" inch on the stick with the single line being about 1" up.
2) I pulled up the strainer and found nothing that stood out. The fluid level is about 1/2" down in this section.
3) I see no leaks in any lines. I've always had a small leak from one of the quick disconnects at the joystick and I've always had a little leakage while running out the breather of the dipstick behind the seat.
4) I have not performed the last task yet.

 

[NorTracNY]

Its a small reservoir and very easy to loose prime to the pump. Loose the pressure (small) line going from pump to lift under seat. Fill reservoir with oil start engine you will get a pressure spray of oil out the loosened pressure line. tighten it and go.
The reservoir is a bit small when working with fel and on hilly terrain.

I did lose the hydraulics with the tractor going up an incline at the time. Shouldn't I have gotten them back now that it's back down and level? When you say fill the reservoir with oil, are you talking about behind the seat where you normally put oil in?

 

[rdbigfarmboy]

No when the pump runs out of oil it cant deal with air and will stop pumping. So vent the line and start it up. you will loose some oil in the process maby not too much. I have a foton 404 and it occasionally does it in steep hills.

 

[NorTracNY]

No when the pump runs out of oil it cant deal with air and will stop pumping. So vent the line and start it up. you will loose some oil in the process maby not too much. I have a foton 404 and it occasionally does it in steep hills.

OK, I understand. I'll give it a try shortly.

 

[Rich Waugh]

The hydraulics on the Jinma are open-center systems and should be self-priming. You shouldn't need to open any lines, but it won't hurt anything either.

Your problem, from what I read, is that you're terribly low on hydraulic fluid. That single line on the lift box dipstick is the full mark. It is ready by unscrewing the dipstick, wiping it and then setting it back on top of the hole, but not screwing it back in. If you screwed it in to read it, you will be low because the dipstick is now down farther than intended. Since your fluid is well below that line, you're really low. It may take a couple or three gallons to get the level up where it should be, which is right to the line - with the stick resting on the hole, not screwed in.

Once you have filled with with the recommended AW32 hydraulic fluid, start it up and operate the steering and lift box controls - it should pull fluid and begin pumping within a minute or two. The lift box sump is just enough above the level of the hydraulic pump to prime it just fine if the lift box is properly filled.

 

[NorTracNY]

OK, so I went out and added more fluid and left the line below the seat cracked open. I then started the engine and tried to use the bucket. I had no luck and then cracked it at the pump itself. There was only a little fluid that came out, which was likely just what was at the line.

Rick - does your stick screw all the way down? No stick even came with the tractor from Northern, so I bought one from Affordable. It does not screw all the way down. I also have always had a little fluid come out every time I use it. One other question is, is it normal for me to need higher RPMs for more power in the hydraulics?
When I added more hydraulic fluid, I put it in with the filter out below where the seat is. I added till that section was full. If I add more, than it would mean that when correct amount of fluid is in the filter could not be removed without first draining a lot of the fluid. I use AW32 hydraulic fluid that is non-foaming (took a long time to find this!)

 

[Diamondpilot]

Lets make sure you have this right.

You have the sump full now. The pump pulls fluid from the sump through the strainer under the seal and through the solid steel line that runs down the right side of the tranny to the pump. From the pump there should be a short 12" or so piece of rubber hose with a Quick Connect on it.

Take the QC off and put that short piece of hose in a bucket. With everything else tightened up try cranking over the motor with the compression release engaged and the fuel shut off pulled out. This should allow the pump to pump fluid into the bucket without the motor starting. If it does not pump fluid the next step is to remove the pump and find out why? Could be a broken coupler or a pump that went south.

Chris

 

[rdbigfarmboy]

There was only a little fluid that came out, which was likely just what was at the line.

You still need to prime it, it sounds like oil is not getting to the pump and it can gravity feed once the AIR is removed. The pump should gush oil under some presssure.

 

[NorTracNY]

Lets make sure you have this right.

You have the sump full now. The pump pulls fluid from the sump through the strainer under the seal and through the solid steel line that runs down the right side of the tranny to the pump. From the pump there should be a short 12" or so piece of rubber hose with a Quick Connect on it.

Take the QC off and put that short piece of hose in a bucket. With everything else tightened up try cranking over the motor with the compression release engaged and the fuel shut off pulled out. This should allow the pump to pump fluid into the bucket without the motor starting. If it does not pump fluid the next step is to remove the pump and find out why? Could be a broken coupler or a pump that went south.

Chris

Thanks! I was backwards. I was loosening the ends of the solid line (input to the pump). Good to know I can just spin the motor with the compression released and move the hydraulic pump. I'm not certain if there is a QC on the output, but I'll check shortly.

So is it normal that the engine needs to run at higher RPMs for more power in the hydraulics?

 

[J_J]

If the pump is not worn badly, it should pump and provide the specified pressure/force at the git go.

Your tractor relief is probably set for 2200 psi.

You only get max pressure when you max out a cyl, or lifting a heavy load. The relief will activate at the relief pressure.

Rpm's is what provides the GPM's for the speed of operation.

If you are at idle, the hyd will work and should be able to lift the specified load. If at high rpm, the hyd will lift the specified load faster.



This night have some bearing on your problem.

Excerpt: from this manual. http://www.atlanticimports.ca/jinma_manual.pdf

Don't know where the asterisks came from.

1. The*pump*must*be*primed*and*will*not*normally*pickup*oil*from*the*filter*due*to*air*which*is*now*in
the*intake*line.*To*aid*in*priming*connect*the*2*mid*ship
hydraulic*quick*connects*together*by*disconnecting*the*FEL
and*butt*connect*them*together.*This*is*the*same*way*your
tractor*was*shipped*prior*to*installing*the*FEL.*If*you*do*not
have*an*FEL*then*this*is*not*necessary.*
2. Start*tractor*for*approximately*1*minute*and*check*for*leaks.
If*you*listen*carefully*you*should*hear*the*pump*pick*up*oil
almost*immediately*and*prime*itself.*Shut*off*the*tractor*after
1*minute.
1. The*pump*must*be*primed*and*will*not*normally*pickup*oil*from*the*filter*due*to*air*which*is*now*in
the*intake*line.*To*aid*in*priming*connect*the*2*mid*ship
hydraulic*quick*connects*together*by*disconnecting*the*FEL
and*butt*connect*them*together.*This*is*the*same*way*your
tractor*was*shipped*prior*to*installing*the*FEL.*If*you*do*not
have*an*FEL*then*this*is*not*necessary.*
2. Start*tractor*for*approximately*1*minute*and*check*for*leaks.
If*you*listen*carefully*you*should*hear*the*pump*pick*up*oil
almost*immediately*and*prime*itself.*Shut*off*the*tractor*after
1*minute.

If you install a hyd gage, you can observe the pressure required to operate the cyl on the tractor.

 

[greg_g]

x2, vented systems are self-priming. Don't waste time on that. But I gotta ask again - have you checked the level of your engine oil? If it's normal, then the pump seal is ok. But if it's not, any hydraulic fluid you add will eventually end up in the crankcase. If/when the level gets too high, the engine can hydro-lock.

//greg//

 

[NorTracNY]

x2, vented systems are self-priming. Don't waste time on that. But I gotta ask again - have you checked the level of your engine oil? If it's normal, then the pump seal is ok. But if it's not, any hydraulic fluid you add will eventually end up in the crankcase. If/when the level gets too high, the engine can hydro-lock.

//greg//

I actually didn't check that. I will when I get a chance tonight.

I will go ahead a see if it will priming it also. I'm really thinking that it is the gear pump at this point. From people's coments here is sounds like I've always had some problem that has now reached the failure stage. I've always experienced that I've needed to increase RPMs to get full power to the FEL. I've always had some hydraulic fluid leak out the vent hole in back of the seat.

Tonight I plan to check the engine oil. If that's fine I'll put the hose from the gear pump into a bucket and get the engine to turn with the compression lever up. If no hydraulic oil comes out, should I then remove the gear pump?

 

[NorTracNY]

Also, where is the pressure release on this tractor? I have one person saying that the gear pump could be ok, but the pressure release could be bad.

 

[greg_g]

Also, where is the pressure release on this tractor? I have one person saying that the gear pump could be ok, but the pressure release could be bad.

As stated, it's a vented system. No pressure release per se, except what's provided through the loader valves. There is a sort of a bypass in the sump that kicks in if/when the lift cylinder hits the stops, but - when the loader's not connected - that's about it.

//greg//