1967 JD 4020 hydraulic leak.

eric2381

New User
Hello.

I'm a new member. Hello to everybody.

I need some help please.

A year ago I bought a 1967 John Deere 4020. Does not have 3 point hitch. It's got a good loader and a bale spear on it. I don't use it much, lifting and moving maybe 20 round bales a year. And a bit of snow removal and general jobs.

When I got it, I'd steer to the right and it would move a bit but then slow up, then all of a sudden go. And a few times, not always, the loader hydraulics would be chattery lifting the loader up to begin with when it started. Not every time, maybe 1/4 of the time.

Anyways, I used the tractor today to move a bale, and after I parked it I saw it was leaking hydraulic fluid pretty bad. In front of the engine but behind the fuel tank. Forgive me, but I'm pretty sure that's where the hydraulic pump is.

I think there's a valve in the hydraulic pump that can fail and cause the chattering and poor steering?? Am I right? If so, Can that also cause the hydraulic leak I'm now getting?

Or is my pump shot and needing rebuilt?


I can post pictures up tomorrow in the daylight as well.


Thanks for your time. Eric
 

Welcome to YT
Hyd leak could be pump,steering motor or pump seal bleed line. One needs to inspect to determine where leak originates. On subject of loader chattering how long since hyd filter was changed & trans oil sump screen checked/cleaned? What type trans & loader control valve does your tractor have???
 
(quoted from post at 17:32:54 06/10/17)
Welcome to YT
Hyd leak could be pump,steering motor or pump seal bleed line. One needs to inspect to determine where leak originates. On subject of loader chattering how long since hyd filter was changed & trans oil sump screen checked/cleaned? What type trans & loader control valve does your tractor have???

Hello. Thanks a lot.

It's the synchro range tranny.

The loader control levers are on the left side of the steering wheel console.

I doubt the trans oil sump screen and hyd filter has been cleaned/changed in a while. I know I haven't. I've been bad, bought it and have just been using it. Checking fluid levels is about it so far.
 
I've hardly used it and what I did use it for was easy going puttering around my acreage work. Moving some bales for my hogs and lifting a few welding machines etc.

I do want to use it to power a mixer mill in the future. And a baler.

I pulled the air filter yesterday out of curiosity while I had it exposed, and it was packed with dirt and dust. So I'm going to guess that the rest of the tractors filters and screens need replacing/cleaning as well.



Would be nice if it was a line that's leaking.
 
Holding the clutch down could cause the chatter, depending on how the loader is plumbed . If the return line is going back to the transmission you will run out of oil as the trans pump is good for abt. 4-5 gal at 1900 rpm . Did you check oil level ? that small leak can get rid of a lot of oil quick . I am guessing you have a blown O-ring on the piston plug on the side of the pump , there's 8 of them with maybe half of them accessible . Also the steering motor seals as well. If you have a wide front end this makes the job more difficult without a hoist or better yet a fork lift .
 

I did check the hyd fluid level, and it's still good. But definitely leaking hard. Since I've owned it it's always been a bit wet around that area, but never anything really on the ground or noticeable. Until yesterday.

Does the pump need to be pulled to repair it?
 
I would suspect you have more than one issue. The first thing I would do is check the inlet screen and change the filter on the transmission. There is a charge pump in the transmission that is engaged when the clutch is out, so clutch in/out differences can show up. I would next check the flow from the charge pump, if both good, then check standby pressure.

The front pump should have a leak line that runs back to the transmission near the batteries.
 





Washed it all off this morning. Let it dry. Started it up this evening to better see where the leak is coming from, and it's coming from under the hydraulic oil cooler. Can see in the pic the shiny, glistening oil. It really leaks out.


I found and know where the hydraulic filter and screen are. I'll be sure to clean and replace once I get the leak fixed.


Would anybody have a solid guess where the hydraulic leak is coming from? And most likely does the pump need to be removed??

I haven't worked on this tractor much. But I'm not mechanically stupid. But am short on time to do a big job on it.

Thanks, Eric
 
If you look in from the left side down at the oil cooler there is a very short hose that runs from the pump to the cooler it may be bad don,t use heater hose get it from JD
 
(quoted from post at 19:04:50 06/11/17) If you look in from the left side down at the oil cooler there is a very short hose that runs from the pump to the cooler it may be bad don,t use heater hose get it from JD


Hello.

Thanks a bunch. That's exactly where it's leaking from. And you nailed it, the previous owner had replaced it before with orange heater hose. And it got soft and blew out.

I'll get the proper hose from JD.

Any tricks to replacing it?

Also, to remove and clean the screen and replace the hydraulic filter, do I have to dump the fluid or can it be left in?

Thanks, Eric
 
There is a hollow cap screw on top of the pump take it out and you can replace the hose there is two o.rings on it top and bottom cut the new hose just a little short ,very little and yes you need to drain the trany to replace the screen
 
That little hose between the pump and the cooler was the
problem. And you guessed it, the previous owner replaced it
once before with orange heater hose. I'll get the proper one
from JD.

I want to replace the hydraulic filter and clean the screen, as
I have no idea when it was done last.

Is there a way to do the filter and screen without draining all
the fluid?


Also, any tips or tricks to replacing that hose?

Thanks again.
 
Went to the JD dealership and got a hose and a new filter. Changed the hose, and parked on a steep side slope and changed the hydraulic filter and pulled and checked/cleaned the screen. The screen was pretty clean and would've had lots of flow. Topped up the hydraulic fluid and moved a bale for the critters and everything worked fine.


Thanks for the help.
 

In lieu of draining trans oil before checking sump screen one can insert the nozzle of an operating shop vacuum into hyd filler hole with remainder of hole blocked off with a shop towel to create a vacuum.
 
(quoted from post at 17:16:59 06/13/17)
In lieu of draining trans oil before checking sump screen one can insert the nozzle of an operating shop vacuum into hyd filler hole with remainder of hole blocked off with a shop towel to create a vacuum.

Thanks. That would've worked great I'm sure. I parked it on a slip and moved fast. Haha. Hydraulic oil everywhere though.
 
(quoted from post at 06:09:32 06/13/17)
(quoted from post at 17:16:59 06/13/17)
In lieu of draining trans oil before checking sump screen one can insert the nozzle of an operating shop vacuum into hyd filler hole with remainder of hole blocked off with a shop towel to create a vacuum.

Thanks. That would've worked great I'm sure. I parked it on a slip and moved fast. Haha. Hydraulic oil everywhere though.


Hi just wondering how you changed the short hose at the bottom
of the oil cooler and what was the part number for the new hose I have the exact same problem I m working on thanks any help would be appreciated
 

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