Hydraulic Pump pressure relief problems

[Gary Baxter]

I have an 08 Jimna Tractor 254 LE w/loader. Split the housing on the hydraulic pump-replaced with new hydraulic pump. Blew the seal on new pump. Found quick disconnet was faulty/broken internally. No QD in system now. Think there may be problem in the pressure relief valve in the hydraulic control valve. How do I troubleshoot this? Any help will be appreciated.

 

[JohnDeere4300]

I have an 08 Jimna Tractor 254 LE w/loader. Split the housing on the hydraulic pump-replaced with new hydraulic pump. Blew the seal on new pump. Found quick disconnet was faulty/broken internally. No QD in system now. Think there may be problem in the pressure relief valve in the hydraulic control valve. How do I troubleshoot this? Any help will be appreciated.

WELCOME TO TBN!

Hope you enjoy it here, and hope you get your tractor fixed.

You can post your question here Chinese Tractors - TractorByNet.com and they will find your question much faster.

Hope that helps and Good-luck.

 

[MossRoad]

Welcome to TBN!

I moved this post to this forum. As mentioned by johndeere4300 you will have a better chance of a reply here.

 

[J_J]

I have an 08 Jimna Tractor 254 LE w/loader. Split the housing on the hydraulic pump-replaced with new hydraulic pump. Blew the seal on new pump. Found quick disconnet was faulty/broken internally. No QD in system now. Think there may be problem in the pressure relief valve in the hydraulic control valve. How do I troubleshoot this? Any help will be appreciated.

Do you know the pressure of the pump?

Tee in a gage at the pressure line going to the valve. Activate the valve until it builds up pressure close to the pump pressure, and watch the gage. It should relieve before it reaches max pressure. You should be able to hear it relieve. If it goes to max pressure and doesn't relieve, then the relief valve needs adjusting or replaced. Do not activate and hold for more than a couple of seconds, or you might need another pump.

 

[greg_g]

Think there may be problem in the pressure relief valve in the hydraulic control valve. How do I troubleshoot this?

Not sure what you mean by this. What specific device are you calling the "hydraulic control valve"? There's a priority (diverter) valve that routes fluid as demanded by the steering controller. Pretty sure pressure relief on that circuit is simple bypass inside the controller. The rear lift pressure relief is internal to the hydraulic sump. Only other pressure relief I can think of would be associated with the front loader - if so equipped.

//greg//

 

[erj]

As JJ said, put a steel T fitting in as shown so you will know what pressures you are operating at.
RonJ

 

[3RRL]

I have an 08 Jimna Tractor 254 LE w/loader. Split the housing on the hydraulic pump-replaced with new hydraulic pump. Blew the seal on new pump. Found quick disconnet was faulty/broken internally. No QD in system now. Think there may be problem in the pressure relief valve in the hydraulic control valve. How do I troubleshoot this? Any help will be appreciated.

Hi Gary, welcome to TBN.
Since you had QD trouble, I presume you have a loader on your 254, right?
So I'm guessing the hydraulic control valve is the fel valve?
Your pressure line from the hydraulic pump probably goes to that fel valve. There is no pressure relief on or inside that pump. The pressure line then goes from your fel valve back to the 3pt valve. The pressure relief valve is in the fel valve and there is also one in your 3 point lift valve. The faulty QD would block the flow and blow the pump (or seals).

I'm pretty sure the psi is rated for somewhere around 2280psi.
So when you install a pressure guage you need to be using either the fel valve or 3pt to check the psi with a relief valve to be in the loop. If you check it directly from the pump, there is none. You risk blowing the pump again. You can then set the pressure relief valve on the fel valve to about 2250psi. There should be instructions in your manuals to tell you how to adjust the relief on the 3pt valve, but I'm not sure about that. Normally, it is set at the factory and needs no adjustment ... (at least mine were good).

One think I did was install a pressure relief valve right off the hydraulic pump just in case I did not have the QD's on correct or if they were faulty or even If I didn't remember to connect them. That prevents the the pump from blowing up. I got one from Surplus center. It has a return to sump for the relieved fluid. You might consider adding one.
Another thing is if you are ever going to remove your loader, you need to hook up the pressure line to the rest of the tractor so the 3pt still works. If you forget to do that, you could blow the pump. That's also why you need the QD's when removing the loader. Most guys have replace their Chinese QD's with aftermarket QD's for that exact reason. You can get them from Ronald (Ranchhand Tractors) or Tommy (Affordable sales) or from Discount Hydraulics or Surplus Center. Some guys have even taken the check ball out of them so there is no interrupted flow.

Those are a couple of suggestions.
Again, I don't know for certain whether you have a loader of not, but if you do, what I said will help. If you are interested, I did a lot of hydraulic work on my wife's 284 Jinma. You can go to these threads and read about them. There are lots of photos that might help.
Rob-
Click here then go to post #130 My New Jinma
Here is a thread about a New Ranchhand FEL Valve
And a thread about New Mods to Loretta's Tractor where the 284 was improved even more.

 

[RonMar]

Another way to check the relief pressure is to remove a line on one of the working ports(lines that go out to the loader cylinders) on the loader control valve and screw a pressure gauge directly into this port. Put the hose you removed into a bucket in case you work the lever the wrong way during the test. Move the control lever to send fluid to this port, and the gauge will read the pressure that the relief is relieving at. What type loader do you have on the tractor? If chinese, you may need a metric adapter to screw the gauge into the port. I would guess if it is a chinese loader, it probably has a straight metric to "O" Ring Face Seal(ORFS) adapters already in the working ports. The hoses screw onto these adapters. You will probably need a male 18 X 1.5mm to Female 1/4" NPT adapter. Someone with a chinese loader chime in here please, as I have a chinese backhoe that uses these, and I am assuming they are the same size. You could take one of your metric-ORFS adapters along to a hydraulic shop to get the correct dimensions for a metric-NPT gauge adapter.
A 1/4" NPT, 0-5000 PSI gauge and metric adapter can be had for probably less than $30. The benefit of the "T" on the valve inlet line, is that you can just leave it there like I have done, but if it is a Chinese valve with metric ORFS fittings on the hose ends, it may be difficult to add a "T" at that point. A "T" in the main line will also allow you to see what pressure the relief on the 3PH control valve is relieving at. Mine was set too high at 3000 PSI and I had to lower it's relief point.

Another option instead of replacing the Quick Connects is to simply remove the check balls and springs from them. Since the male and female ends on the tractor side are either connected to the loader or to each other when the loader is removed, the check balls are realy not needed. A little oil will be spilled if you have to swap the connections around, but you won't have to worry about a bad ball or spring assembly clogging the main line, and if one accidently gets separated, it will just pump fluid and not deadhead and kill the pump. It is easy to remove the ball and spring. Simply unscrew the QC fitting from the hose end. Inside where the hose was threaded you will find a snap ring, a spring retainer plate, a spring and a ball. Take all this out and re-install the QC fitting onto the hose end. If you are going to do this, THIS MUST BE DONE ON ALL 4(2 male and 2 female) QC FITTINGS...

 

[Gary Baxter]

Thanks to everyone for the help, I have not yet fixed it, but I'm going down to get the bucket cylinder which was bent as well. This is my first time using the forums so I am having my grandsons help me with the typing and they are also helping me comprehend the whole function of these "forums". Thanks again for all the help.