2020 all hydraulics quit

[sundreams]

Edited: found the filter releif valve- not the issue.....still no hydraulics

Long story short- how do i remove and clean/repalce the oil filter pressure relief valve on a 2020? i THINK that is my issue- or one of them.

Longer story: I have a JD 2020 ('71 pretty sure) i got from a neighbor over the winter. Bad brake valve when I got it, had pretty dirty hydraulic/trans oil. Had someone replace brake valve, flushed lines, replaced oil. It ran fine until last week when all hydraulics just quit. No loader, no rockshaft, no power steering. Probably no brakes but havent tried to move it.

There is a small plastic line running from under hydraulic pump to above the reservoir check valve. It is not clamped on, probably was a some point in time. During operation the line came off, spilled quite a lot of oil before being noticed. This happened three times. Each time oil level was returned to proper height. Last time this happened, my father in law was brush hogging- he noticed it, stopped, put line back on, we checked oil level- and then zero hydraulics when started back up.

Hydraulic and trans pump seem to be working (filter housing had oil in it after being changed- ie trans pump is working? and hydraulic shaft turns with engine- opening plug on pump and turning engine oil pours out- ie hydraulic pump works?) Am i right so far?

Cleaned the screen- which was beyond filthy. Replaced filter. From the tech manual looks like filter pressure reief valve is most likely next- makes sense if the screen was blocked that the dirty oil got some debris stuck in the valve? Next option i believe is the pressure control valve- guessing cleaning all valves would be a good idea at this point.

Located plug on oil filter relief valve, but the tech manual doesnt give any indication on how to remove or inspect the valve itsself. Lots of gunky oil behind the plug. Can see the roller pin but no clue how it is removed- or if it can be cleaned without removing?

Found a video of a guy with a 2030 he quickly mentioned he removed his valve when he split the tractor- if the valve is the issue really dont wanna split it.

Any insight is greatly appriciated.

PS I love to fix stuff but am by no means a skilled mechanic. Learning as I go here.

This post was edited by sundreams on 08/21/2022 at 06:55 am.

 

[Jim.ME]

(quoted from post at 18:07:02 08/10/22) Long story short- how do i remove and clean/repalce the oil filter pressure relief valve on a 2020? i THINK that is my issue- or one of them.

Longer story: I have a JD 2020 ('71 pretty sure) i got from a neighbor over the winter. Bad brake valve when I got it, had pretty dirty hydraulic/trans oil. Had someone replace brake valve, flushed lines, replaced oil. It ran fine until last week when all hydraulics just quit. No loader, no rockshaft, no power steering. Probably no brakes but havent tried to move it.

There is a small plastic line running from under hydraulic pump to above the reservoir check valve. It is not clamped on, probably was a some point in time. During operation the line came off, spilled quite a lot of oil before being noticed. This happened three times. Each time oil level was returned to proper height. Last time this happened, my father in law was brush hogging- he noticed it, stopped, put line back on, we checked oil level- and then zero hydraulics when started back up.

Hydraulic and trans pump seem to be working (filter housing had oil in it after being changed- ie trans pump is working? and hydraulic shaft turns with engine- opening plug on pump and turning engine oil pours out- ie hydraulic pump works?) Am i right so far?

Cleaned the screen- which was beyond filthy. Replaced filter. From the tech manual looks like filter pressure reief valve is most likely next- makes sense if the screen was blocked that the dirty oil got some debris stuck in the valve? Next option i believe is the pressure control valve- guessing cleaning all valves would be a good idea at this point.

Located plug on oil filter relief valve, but the tech manual doesnt give any indication on how to remove or inspect the valve itsself. Lots of gunky oil behind the plug. Can see the roller pin but no clue how it is removed- or if it can be cleaned without removing?

Found a video of a guy with a 2030 he quickly mentioned he removed his valve when he split the tractor- if the valve is the issue really dont wanna split it.

Any insight is greatly appriciated.

PS I love to fix stuff but am by no means a skilled mechanic. Learning as I go here.

Do you have John Deere manual SM2072? Mine has info on all the valves.

 

[Jim.ME]

"[color=red:7262f06ee5]There is a small plastic line running from under hydraulic pump to above the reservoir check valve. It is not clamped on, probably was a some point in time.[/color:7262f06ee5]"

The plastic line (pump seal bleed line) is supposed to have flared ends held to the fittings on the pump and reservoir with a nylon tubing nuts. You might want to consider getting a new line, and fittings, if yours are missing, from JD. Or with the right fittings, clamps, and some oil resistant hose you could make your own line.

"[color=red:7262f06ee5]Located plug on oil filter relief valve, but the tech manual doesnt give any indication on how to remove or inspect the valve itsself. Lots of gunky oil behind the plug. Can see the roller pin but no clue how it is removed- or if it can be cleaned without removing?[/color:7262f06ee5]"

By the manual, remove the plug then pull the sleeve that contains the valve. (Pulling may require some hooks and creative ideas, but it will come out.) The manual describes servicing the valve once the sleeve is out of the tractor.

As for the main pressure control valve. If you want to clean it on the bench, the entire pressure control valve removes from the side of the transmission by unhooking the tubing lines and removing the capscrews holding it to the transmission case. Servicing is described in the manual. Some maintenance can be done to it in place.

Most equipment service/shop/technical manuals were written for dealer mechanics who may have had training or at least experience with systems and will not have the detailed step by step information you may find in auto DIY manuals.

 

[Tx Jim]

Welcome to YT
Check to be sure frt hyd pump driveshaft turns when engine crankshaft turns

 

[rrlund]

Does it have a destroker on the top of the pump? If it does, turn it in while the tractor s running, then turn it back out. Sounds
like you have some of that crud that you describes, stuck in there. Opening the destroke will dislodge it.

 

[sundreams]

it does turn

 

[sundreams]

do not have destroker on the pump... getting into that valve is next on the list.

 

[sundreams]

Thanks for the suggestions so far...trying to figure out the "reply" vs "quote" thing here on the forum. I thought i had notifications turned on here but i guess not-


I did end up figuring out just had to pull harder on the pressure relief valve...hadnt wanted to damage anything at first. It was filthy. Cleaned the valve. started engine for a few rotations, the transmission pump pushed out some more gunky oil from the valve housing- reinstalled. No change.

checked inlet line check valve- cleanest thing ive seen on this tractor yet.

Pump shaft does turn when engine turns.

Pulled a plug that i THOUGHT should be the surge relief valve- nothing in the hole. Plenty of murky oil came out, but no spring or anything else to be seen. I either didnt find the right plug, or someone once upon a time removed it? The plug i removed was on the right side of clutch housing, just above the foot throttle (not sure thats what it is called- but you get it)

Working down the diagnostics in manual I am down to stroke control valve, and possibly crankcase outlet valve. I do NOT have the manual destroker on my hydraulic pump.

Have not looked into the pressure control valve yet- but i THINK if that were the issue i would have power steering?

 

[Jim.ME]

"Pulled a plug that i THOUGHT should be the surge relief valve- nothing in the hole. Plenty of murky oil came out, but no spring or anything else to be seen. I either didnt find the right plug, or someone once upon a time removed it? The plug i removed was on the right side of clutch housing, just above the foot throttle (not sure thats what it is called- but you get it)"

It is a plug, it only drains that cavity.

 

[sundreams]

Ah well that feels better than a missing valve. Any guidance on where that valve is located? From memory all i got from the manual was right side of clutch housing. Haven't looked that hard though since finding that drain plug...I only get about an hour at a time I can work on it.

 

[hedgeless_horseman]

My 820 is similar to your 2020, and it had the same issue with hydraulics not working. Here are two threads that might help:

https://forums.yesterdaystractors.com/viewtopic.php?t=1565557&highlight=

https://forums.yesterdaystractors.com/viewtopic.php?t=1529597&highlight=

 

[Tx Jim]

JD 820 utility tractors have open-center hyd's while 2020 has closed center hyd's which operate very differently with totally different diagnostic procedures required.

 

[hedgeless_horseman]

Well, at least my thread proves that a rank amateur can split his tractor in his garage and get it back together and working, with your expert help.

 

[sundreams]

(quoted from post at 15:56:28 08/16/22)
"Pulled a plug that i THOUGHT should be the surge relief valve- nothing in the hole. Plenty of murky oil came out, but no spring or anything else to be seen. I either didnt find the right plug, or someone once upon a time removed it? The plug i removed was on the right side of clutch housing, just above the foot throttle (not sure thats what it is called- but you get it)"

It is a plug, it only drains that cavity.

So i did find the surge relief valve- right next to brake valve- doesnt appear to be fouled in any way. From what I can tell the issue is likely within the pump itsself, either the stroke control valve, crankcase outlet valve, or something else altogether broken?

ANy advise on troubleshooting from here?


Working down the manuals diagnostics for "no pump output" and "slow or no hydrualic functions" the only thing i believe it could be at this point is:
-"improper stroke control valve adjustment"
-"stroke control valve failure"
-or "crankscase outlet valve failure".
-I believe if it were pressure control valve set too high (or just gunky?) I would have power steering but no other hydrualics? I DO NOT have power steering.
-low standby pressure- what could cause low standby pressure, other than failing valves somewhre in the system?

What i believe i have eliminated:

-broken pump shaft (it cranks with the engine, unless it broken inside the pump thats not the issue)
-transmission pump failure (transmission pumps oil through pressure releif valve port when plug is removed
-inlet line check vavle failure - looked clean and in good order when removed
-surge releif valve failure- looked clean and in good order when removed
-filter releif valve failure- was super gunky- cleaned, replaced, no change-
-plugged transmission failure- new filter
-optional transmission coltrol valve malfunction- dont have that option

-low transmission oil level- checked and topped up


I did remove the plug on top of the stroke contorl valve- appears to be clean oil in there- hard to see anything though with the radiator and oil resevior in the way there. Not clear if the valve can be removed and inspected/cleaned from the top port? didnt spend much time on that yet.

Am i correct that the rockshaft valve etc would have NO affect on front end loader or power steering failure so the issue would not be within the rockshaft area?

Any and all help is appriciated. I just wanna finish brush hogging my fields

 

[Tx Jim]

Have you checked/cleaned trans oil suction screen? What type valve controls frt end loader? Leaking rockshaft control valve/seals will have an adverse affect on tractor hyd system operation.

 

[sundreams]

Yes screen was first thing I checked... it was horribly gunky. And unfortunately not the (only) issue.

 

[Tx Jim]

What type valve controls frt end loader?

 

[sundreams]

(quoted from post at 17:04:32 08/21/22)

What type valve controls frt end loader?

I dont know... forgive my ignorance. How can I tell?

 

[Tx Jim]

You could post a photo of your loaders control valve. What brand/model loader do you have?

 

[sundreams]

(quoted from post at 17:16:31 08/21/22)
You could post a photo of your loaders control valve. What brand/model loader do you have?

Ok I will post a photo later. Its a plate with a hydrualic in and and out, two joysticks- That description probably doesn't help.

Also no clue model of loader. Believe it's a deere but without going to look closer no clue about any other details. Will check thus evening.

 

[Tx Jim]

FEL control valve needs to be for a """closed-center hyd system""" that JD 2020 has.

Simple test is remove FEL control valve return hose that is attached to tractor hyd system. Cap orifice on tractor then with joystick in neutral aim open return hose in open hyd filler behind seat. Start engine & no oil should exit open return hose with JS lever in neutral. If oil exits open hose the FEL hyd control valve is contributing to your tractors """poor hyd performance""".