Jinma Hydraulic Pump - Failures

[wdchyd]

I did away with my quick connects for this very reason. My Jinma 284 uses 1/2 fittings so I just put in swivel unions.

Chris

QC's just downsteam after a positive displacement pump (dumb pump) makes me nervous, anything bad can happen

 

[Leejohn]

I can't think of any reason to have QC's off of a pump pressure feed to the 1st relief.

 

[RonMar]

I can't think of any reason to have QC's off of a pump pressure feed to the 1st relief.

Other than to make it easier to remove the FEL

 

[Leejohn]

I forgot about some loaders the valve goes with the loader. But doesn't pump go to the main relief first or they just use the 3pt relief when loader is off?

 

[Bob Rooks]

I forgot about some loaders the valve goes with the loader. But doesn't pump go to the main relief first or they just use the 3pt relief when loader is off?

I believe the main relief valve is located in the FEL valve stack.

 

[Circle G Tractors]

Those quick disconnects are usually the culprit on those jinmas causing the backpressure problem splitting the case on pump, also check the loader valve for the problem as mentioned, we have seen that cause the pumps to fail as well, those two things are usually what causes the pump failures on the chinese units.

Ben
Circle G Tractor Sales, inc.
Jinma Tractor Parts, Farm Pro Tractor Parts, Farmpro, Nortrack, Agracat

 

[SPIKER]

My 1st pump (factory one) failed after my brother decided it was greasy and pressure washed it sending 3500PSI water into the pump body seals from the wrong side. well I bought a rebuild kit for it along with a NEW pump from Tommy. I rebuilt the Factory Pump and re-installed it but could not get he pump to spin over. The end plates may have been warped or? in any case the pump would not turn by hand or by engine. I simply tossed it aside and installed the NEW pump and went back to working. These things are not complicated, as stated quick disconnects are #1 pump failures either by accident (brush knocking them apart) or by owner disconnecting them while engine was running. That is usually pretty dramatic failures or they can blow the shaft seal and pump crankcase full of hyd fluid. I bought & sold a few and one of the NEW owners of one's DAD did this splitting the pump side pretty bad. I had a spare pump at that time & gave it to him to get him back to running.

Mark

 

[doxford jim]

Hi guys,

Thanks for the interesting comments, I am always learning something new. When clearing snow using both the TPH snow blower and the FEL, it is normal for both to be in the raised position when moving from one place to another. I have done that for years and don't think that is the cause of the pump blowing. Having said that, the TPH blower isn't raised any higher than needed, whereas the FEL is used as needed. Obviously when blowing snow the blower is on the ground and the FEL usually a couple of feet off the ground - high enough to clear the newly cleared snow edges of the driveway/road.

I am thinking that the cause was probably the QD's connects though I will never know for sure.

To add to my other comments, I have now installed a pressure gauge and the original Jinma QD's have the internals removed and are now open.
I will put in an extrenal relief valve along with a dedicated dump line back to the hydraulic oil tank. I still have to make up my mind on where to connect the relief v/v return at the tank - either at the drain or at the top of the tank.

Thx

Jim

 

[Jimmy965]

Replacing a 14ml/r pump with a 20ml/r pump, an almost 50% increase in volume without increasing hose and/or fitting internal diameters. Has anyone else done this? I've never tried so I'm curious of the results. It would be ok at low rpm but I'm thinking oil flow at high rpm through the loader hand control and quick disconnects would be restricted. Restricted enough to cause pump damage?

 

[doxford jim]

Circle D - I think you are on the right track. I did not have the extra direct relief valve installed when I put the 20ml/r pump on. Thinking about it, I am sure that the original system would be marginal at best, but with higher engine RPM, failure would most likely occur quickly. That is what happened in my case I am sure.
I should mention that when the QD are removed from the pump outlet (pressure side), you will see the hose to the FEL valve block has a smaller internal dia - maybe 5/16" dia at most. The short pump discharge hose has a bigger ID of around 1/2" The relief vales in the valve blocks may not be too efficitient IMO.

I have since added a 10gpm external relief valve in hyd.pump discharge line and set it to open at 1800psi (18 bar). For what I need the 1800 psi pressure is adequate. I have the hose from the relief valve returning to the hydraulic tank. Set up seems to work well so far. Will try to attach a couple of foto's (taken just a day or two ago) to show what I have done - very similar to what other owners have done also.

Without the extra relief valve it will become expensive - the external relief valve is essential IMO.

Cheers

Jim

 

[EE_Bota]

Circle D - I think you are on the right track. I did not have the extra direct relief valve installed when I put the 20ml/r pump on. Thinking about it, I am sure that the original system would be marginal at best, but with higher engine RPM, failure would most likely occur quickly. That is what happened in my case I am sure.
I should mention that when the QD are removed from the pump outlet (pressure side), you will see the hose to the FEL valve block has a smaller internal dia - maybe 5/16" dia at most. The short pump discharge hose has a bigger ID of around 1/2" The relief vales in the valve blocks may not be too efficitient IMO.

I have since added a 10gpm external relief valve in hyd.pump discharge line and set it to open at 1800psi (18 bar). For what I need the 1800 psi pressure is adequate. I have the hose from the relief valve returning to the hydraulic tank. Set up seems to work well so far. Will try to attach a couple of foto's (taken just a day or two ago) to show what I have done - very similar to what other owners have done also.

Without the extra relief valve it will become expensive - the external relief valve is essential IMO.

Cheers

Jim

I think you have a small typo...in bar, you are running ~ 125 bar. Just clearing up the typo, the work looks great, and I'm jealous my tractor doesn't have an external relief like yours.

 

[Bob Rooks]

1,800 psig = 124.1056 bar or 122.4827 atmospheres.

 

[Don82]

Trying to figure out how the hoses on a Jinma 454 is supposed to run. Installed new pump and need to know if anyone would have a picture to show how to route the lines. Thanks

 

[Cinco]

Sounds like several of my problems and questions have been addressed here. I will get a new filter to start, get rid of my quick connects in favor of direct threaded connections, and check for leaks on the intake side that be taking in air. I don't have any leaks coming out that are that noticeable, but may be taking in air and causing some squishness and slow responses to my hydro requests.
To be sure, I think I only have one location that holds fluid, you fill and check right next to the gear shift lever on top of the transmission. I do not see any other place that may hold fluid. If there is, I sure haven't changed it! Jinma 345 diesel. I think there is a breather at the back behind the seat, but no way to put fluid in there. I will add a pressure gauge to the FEL controls to see what that is reading.
One quick question, I have a hydro fitting at the back of the tractor near the 3 point. There is only one, what the heck is that for? I would think you need 2 to do anything, one power and one return. What good is one connection? Is there a return somewhere I can not find?

 

[EE_Bota]

One quick question, I have a hydro fitting at the back of the tractor near the 3 point. There is only one, what the heck is that for? I would think you need 2 to do anything, one power and one return. What good is one connection? Is there a return somewhere I can not find?

My 304 has a quick connect for a dump trailer on the left. I have a similar looking pipe on the right, but that's to drain the fluid. It could be made into a return easily.

 

[Rich Waugh]

No - that fitting on the transmission is for gear oil, not hydraulic fluid. The hydraulic fluid goes in the lift box, where that breather is. Unscrew it and there's a dipstick. Do NOT put hydraulic fluid in your gear case!

The single remote is for a dump trailer, power up, gravity down.

 

[Cinco]

I spent $2500 last year having the case split to repair busted off shift forks, and the shop put hydraulic in the gear box. They said it ran the whole tractor.
I might have to go look all this up and do some draining/filling if that is the case.

 

[Diamondpilot]

I spent $2500 last year having the case split to repair busted off shift forks, and the shop put hydraulic in the gear box. They said it ran the whole tractor.
I might have to go look all this up and do some draining/filling if that is the case.

The shop has no idea what they were doing. There is a separate hydro reservoir behind the seat.

Chris

 

[RonMar]

One quick question, I have a hydro fitting at the back of the tractor near the 3 point. There is only one, what the heck is that for? I would think you need 2 to do anything, one power and one return. What good is one connection? Is there a return somewhere I can not find?

Yep, that single fitting is most likley for a dump trailer. You close the 3PH speed regulating valve, connect the dump trailer hose to that fitting and use the 3PH control lever to raise/dump the trailer with fluid flowing out the fitting to the trailer. When you lower the 3PH control lever, the weight of the trailer forces the fluid back thru the fitting and into the tractor. This is the same as you do to raise and lower the 3PH which is also a single acting cylinder.

 

[Cinco]

Drained and filled the hydro with fresh fluid and everything works great again. Was not much to drain! Drained the gear case and filled that with all gear oil. It looks like a mix of gear oil and hydro. I should have known something was wrong with that idea, I have a barrel of each sitting in the garage from when I first bought the tractor 5 years ago and did all the changes from the factory gunk. She is running fine and sounds great now. I also had the cooling system apart to replace the lower rad hose and install a hot water heater. A flush and all new fluid with conditioner, and she is staying nice and cool now! I ran it over an hour sitting at a high idle and the needle stayed between 40 and 60 the whole time. My lil Virjinia is happy again.