Dead Heading? What is it?

These tractors use an “open center” hydraulic system. Simply put, fluid has to constantly flow from the pump to the reservoir, and back to the pump. Once you block the flow out of the pump, such as disconnecting the quick connects to the loader and not connecting the two hoses that went to the loader back together before starting the tractor, that would dead head the pump, destroying it. The Chinese quick connects that come from the factory are prone to failure, and while appearing to be connected, may at any time they deem fit, fail and block the flow through the hose, again dead heading the pump. Replacing these with quality quick connects, such as Pioneer brand, is cheap insurance. Some dealers do this on every tractor they sell, most don't. There is a post open right now discussing the installation of a relief valve  on the pressure line coming out of the pump. These can be pre set or adjustable. When pressure builds to meet the relief valves threshold it will divert the fluid to a line you would run to the return tank, keeping the pump safe. Some brands of tractors have this feature from the factory, Jinma for costs or whatever reason chose not to put them on these tractors. With a relief valve installed the chances of dead heading are the same as the failure rate of the relief valve, about 0%. 

As a side note I have not installed a relief valve, yet. I had an issue earlier with the loader valve that caused the dump function to fail, and if it was not corrected right away as I did, would have dead headed the pump. A relief valve would protect the pump in this instance. I got lucky and stopped the tractor right away and fixed the problem.

 On your loader joystick valve block, on the opposite end from the joystick are two cans that look like over sized thimbles, held on by Allen screws. Take these off and you will see a spring under each one with a slot screw in the center of the spring holding them on. Make sure these are TIGHT. They are known to come loose from the factory and were the cause of my valve problem. A ten minute check that can save your pump. There is a smaller can on top of the valve, don't mess with that, It's your pressure relief valve for the loader circuit!

You can also have blocage in your lines. We had a deadhead problem with our Jinma 454 due to a faulty pressure relief valve of the FEL control valve. To fix the problem, we installed a pressure relief valve between the FEL control valve and the pump. We eventually replaced the FEL control valve as we needed the float capabilities on our FEL.

I had a customer one time where his kid messed the the quick connector. I guess he thought it was cool and wanted to see how it came apart.  It was not locked all the way back on.  The guy used the tractor for a few minutes then the connector popped off.  Since the connector has a valve in it that only allows oil to flow when it is plugged in there was no place for the oil to go.  The pump split the housing right up the side.  That's dead heading in a nut shell.  

1#; Could someone please explain what hydraulic deadheading is

2#; and how does it happen when using your loader or other implements?

3#;  I have a 2007 Jinma 354 with ZL 30 loader and y 485 engine.  What needs to be done to protect this tractor from deadheading the hydraulic pump?

1#; To add one word. Hydraulic pump deadheading. The flow of oil coming out of the pump has been stopped, has no where to go. Example; Garden / water hose. If you were to kink the garden hose enough to stop the water flow completely….. you just dead headed. If you kinked just enough to slow down the water coming out ….. you just restricted the flow, not a dead head.

2#; Something in the circuit stop the flow.

3#; To protect for a dead head requires a relief valve. To protect from dead heading….. don't do anything to stop the flow. On your tractor…. there are 3 things I have seen the most that can/has caused dead heading. The factory hyd quick connects & loader control valve. And the draft control sense linkage out of adjustment.

A side note; When a hyd system has a relief valve and is being operated in relief mode …… the oil is getting heated/hot !!!!

Ronald