Hydraulic / adding new remote valves

[Jose G]

Hi guys, i had the chance to educate myself a lot by reading on hydraulic while waiting for parts for my tractor (another thread)

i have a Jinma 254/284 with the old type FEL loader valve (the black one without a power beyond port)

the more i read, the more I understand that most of the tractor (if not all) have a power beyond port on the FEL valve when they need to add remotes.

also, on the INLET of the FEL valve, there is pressure, but when it get out of the OUTLET port, the pressure drop and then it goes to the diverter valve and to the 3pts and finish off to the Hydraulic fluid tank...

I question myself on how the 3pts can work if there is no pressure? (or less / not enough)

if the 3pts works, may i just split the OUTLET hose (of my FEL valve just before the diverter) and add my remotes in series with it? (i think i cannot because of the lack of pressure). i just found information on how to add remote when there was a power beyond port...

I'll probably get the upgraded valve sometime, but my old style is working "ok" for now and not leaking. I would like to add 3-4 remotes... if i really need to upgrade my FEL valve, ill think about it.

thanks

Jose G.

 

[quicksandfarmer]

Upgrading the FEL valve is not necessary. The way that the hydraulic system works is that the valves are all in series, and when one is used all of the upstream valves feel the pressure. So if your current valve can take it when you use the 3-point hitch, it can take whatever pressure the remotes provide. You should be able just to unclip the quick release on the output of the FEL valve and put the new valve in there.

The problem is that you might have trouble finding a valve for the remotes that can take the back pressure from the 3PH, most have very low back pressure ratings. The purpose of a power beyond port is to spare the valve when a downstream valve is being used. A valve with power beyond has three hoses -- input, output, and power beyond. Power beyond goes to the next device (the 3PH) and output goes back to the tank. The tricky part is figuring out where to tie into the tank. Some Jinma's have a spare port on the tank, some have a drain plug that can be repurposed, and some have nothing.

 

[RonMar]

Jose, there is plenty of pressure available from the outlet of the FEL control valve. That flow from FEL to diverter to 3PH is what provides the energy to power the steering and to power the 3PH. This is an open center system. There is no real pressure anywhere untill you restrict the flow by diverting it to perform some work such as sending it to the loader lift cylinders. The fluid returning from the other side of the cylinders continues on downstream from the FEL valve as long as the cylinder is moving or thru the relief valve down stream when the cylinder stops moving. The diverter valve gives the steering system priority over the 3PH. Like Quicksand said, a normal PB valve has 3 main lines connected to it. It has one inlet and 2 outlets. You can add another control valve inline, with the power beyond outlet feeding the other devices downstream of the valve. The other outlet is a low pressure return line and will require a low resistance path directly to the reservoir. The chinese loader valve is designed to withstand high backpressure caused when you lift a heavy load on the 3PH, as is the steering and diverter valve. You can probably connect a return line in near the steering as the steering has a low pressure return path that runs back to the reservoir on the left side of the tractor transmission.

Here is a diagram of the hydraulic flow on my 284.

 

[Jose G]

Hi Ron, I'm not sure I understand the part when you are talking about adding a return line on the steering (maybe you was talking about doing that when used with power beyond? if it's the case, I understand since the PB/new valves would need a return to the fluid tank)

So i could just add my remote valves right after the diverter valve on the same line that goes to the 3pts, in exemple: Diverter ---- Valves ---- 3pts
just a question now, how about the high back pressure of the 3pts ?
Do I have to search for a special feature on the valves or maybe split before the diverter valves since it can withstand the backpressure? (I would like to let most of the fluid to the power steering since I already hate the FEL valve is mounted BEFORE the diverter)

I think I'm about to order my valves and start to figure out where I can mount them.

thanks a lot

Jose G.

 

[quicksandfarmer]

So i could just add my remote valves right after the diverter valve on the same line that goes to the 3pts, in exemple: Diverter ---- Valves ---- 3pts
just a question now, how about the high back pressure of the 3pts ?
Do I have to search for a special feature on the valves or maybe split before the diverter valves since it can withstand the backpressure? (I would like to let most of the fluid to the power steering since I already hate the FEL valve is mounted BEFORE the diverter)

I think I'm about to order my valves and start to figure out where I can mount them.

thanks a lot

Jose G.

The point of power beyond is to handle the back pressure. If you can find a valve rated for high back pressure -- like the one in the FEL -- you can go with a simple two-hose setup, just in and out, with out going downstream to feed the 3PT. Most valves sold today aren't rated for high pressure on the output, the output has to go to the tank (zero pressure) and if there are downstream devices they have to be attached to a power beyond port.

 

[Jose G]

I understand the PB better now. (can withstand back pressure, and it makes sense..), I guess my stock FEL valve keep the pressure on the outlet and can withstand the back pressure.
but I'm a bit mixed up, do i need to change my FEL valve and get a PB port FEL valve or can i find a valve that can withstand the back pressure for my remote? (if so... what special feature on the valves should i look for?)

 

[RonMar]

Yes, I was refering to the return port on a PB valve you add connecting into the low pressure return line that comes from the steering valve and runs back to the reservoir along the left side of the tractor.

No you do not need to change your FEL valve. When you lift something too heavy for the 3PH to lift, the relief valve in the 3PH control valve opens at it's maximum pressure, around 2700 PSI. That pressure is felt all the way back thru the line, thru the diverter, thru the FEL valve and all the way back to the pump outlet. So everything in that circuit is capable of withstanding that pressure...