# JD 1120 Hydraulic question



## davidwl.russell (Oct 28, 2021)

Howdy,
I have had issues with a used tractor I bought. Front loader stopped working not long after purchase. Changed all fluids, cleaned screens and replaced filter. Worked a little better but not much strength. Pump tested OK. Bypassed flow control valve and loader worked fine. Had control valve repaired. All seemed to work OK until I tried to use a haybine and realized rear remotes weren't working. Took selector control valve off, and found it was pooched. Bought a used one and put it in. Now Loader works, but it looks like there's constant 2000psi pressure at the inlet of the control valve for the loader. I have a pressure gauge mounted just before the inlet port of the loader's control valves. I'm pretty sure before I started screwing around with the rest of the system, the gauge showed 0 psi until I tried to lift something with the loader. I don't think there should be (almost)100% pressure there when there is no load being lifted? but the loader does work... I'm worried it might be harmful for the pump or system to always have max pressure- or maybe that's the way it works? Any insight or opinions would be welcome. I've included a diagram of the hydraulic system from the manual.
Thanks, Dave


----------



## Fedup (Feb 25, 2014)

To start with, some of the 10 and 20 series utility tractors were supplied with open center systems, some were closed center. ASSUMING yours is closed. Yes/no?

With open center there should be very little pressure in the main lines until demand calls for it. With closed center there should 2000+ whether there is demand or not. I'm curious how the pump was "tested OK".


----------



## davidwl.russell (Oct 28, 2021)

Fedup said:


> To start with, some of the 10 and 20 series utility tractors were supplied with open center systems, some were closed center. ASSUMING yours is closed. Yes/no?
> 
> With open center there should be very little pressure in the main lines until demand calls for it. With closed center there should 2000+ whether there is demand or not. I'm curious how the pump was "tested OK".


Hey Fedup, thanks for the reply! Not sure if the tractor is open or closed center- a couple of other ppl have mentioned that as well (I've been seeking advice from friends/neighbours and any stranger who happens to make eye contact) do you know how I could check? I managed to get someone to come-out and look at the tractor not long after I first had problems, I wasn't here when he looked at it, but he left me a message (and a bill) telling me the pump tested good. I'd actually be OK paying someone to look at it, but I don't have a float, and can't seem to find anyone local who is knowledgeable/interested, aforementioned person is no longer making house calls. So I'm trying to fix it on my own, not much experience, but I'm learning


----------



## Fedup (Feb 25, 2014)

https://partscatalog.deere.com/jdrc/sidebyside/equipment/82931/referrer/navigation/pgId/248342



Hope this comes through for you. This is what the typical closed center pump looks like for your model. The ring of plugs around the center section is what to look for. An open center pump has only the two ports for the suction and pressure lines, not much else.

So the loader works with it's own dedicated valve and not from the remote valves? Lots of ways to plumb these things, so you need to know what you have in that regard. 

Just guessing, I'd say your previous check amounted to a pressure gauge somewhere and a standby pressure reading that was "okay", and that was pretty much it. I could be wrong. Maybe you could elaborate a bit more on what works and what doesn't.


----------



## Tx Jim (Jul 28, 2020)

Fedup said:


> To start with, some of the 10 and 20 series utility tractors were supplied with open center systems, some were closed center. ASSUMING yours is closed.
> .


1120 will have closed center hyd's. Only 20 series JD utility tractors I can locate with open center hyd system is 820 & 920


----------



## Tx Jim (Jul 28, 2020)

David
1120 closed center hyd's should have 2250 psi at any hyd port when pump shaft is rotating.


----------



## davidwl.russell (Oct 28, 2021)

Fedup said:


> https://partscatalog.deere.com/jdrc/sidebyside/equipment/82931/referrer/navigation/pgId/248342
> 
> 
> 
> ...


Hey Fedup,
The diagram link worked just great, and that's definitely the pump I have- so it looks like I'm OK seeing that pressure as it is. Now I can start using the tractor Thanks for your help, it's much appreciated!!


----------



## davidwl.russell (Oct 28, 2021)

Tx Jim said:


> David
> 1120 closed center hyd's should have 2250 psi at any hyd port when pump shaft is rotating.


Great- thanks I appreciate the input!


----------



## jd110 (Nov 23, 2015)

Your tractor has a closed center hydraulic system it is designed to have full system pressure at all times. It should actually have 2250 - 2350 psi. Stroke control valve in hydraulic pump is adjustable to get correct pressure.


----------

