1020 hydraulic issues

[mb1020]

Hello Everyone, I am hoping someone here can help me figure out what is going on with my 1969 1020 John Deere. I've tried searching all over the web for info and just can't seem to figure it out.

Problems: Steering locks and pulls to right. Loader has poor response but operates. Rockshaft lifts, but usually needs one of the loader valves cracked open.

What I have done: Replaced main pump with a reman pump. (pump had massive shaft leak).
The Hi/low that was originally on the tractor has been removed completely (housing swapped) due to worn planetary gear.

Steering valve was rebuilt, new orings, seals, cleaned & polished valves. ( I have a separate 1020 parts tractor. The entire steering was swapped with the other unit and still has the exact same symptoms).

I have the I&T shop service manual, but not the JD manuals.

Today I hooked up a 3000PSI gauge to the plug port(destroke port) on the main hydraulic pump. The pressure read 1000psi with no hydraulics operating. Is this standby pressure? When the bucket is raised the pressure rises. I tightened the stroke valve about 1.5 turns and gained another 100 psi.

Engine running 1900 rpm.

Additionally the same gauge was attached to the loader input at the priority valve after the loader hose was disconnected. Unfortunately I did not have a cap to plug the open end of the loader input. Pressure read over 3000psi with no operation of the hydraulic functions.

I'm trying to determine if this is a priority valve problem or if something inside is leaking.

Tractor has closed center hydraulics and power steering.

Thanks,
Mark

 

[JDEM]

Do you have the tiny little German pump or the other German pump that is twice the size? Non-splined driveshaft, correct?nd

Stand-by pressure should read over 2000 PSI. If you only have 1000 PSI, either the pump is defective or you have a massive
internal hydraulic leak. When all is as it should be, the pump makes around 2200 PSI with NO flow of oil and kind of shuts
itself off and it takes near no power to turn it.

 

[Tx Jim]

Welcome to YT
If you have to move frt end loader control valve for 3 pt to raise then I suspect loader valve is an open-center not closed center valve or CC plug in valve has a blown seal.

With loader control levers in neutral remove loader valve "return hose" from tractor then place open end of return hose in open hyd filler hole behind seat. Start engine & no oil should exit open valve return hose with control levers in neutral.

 

[gene g]

Sounds like loader maybe plumbed in front of priority valve like Jim and JDEM said this will rob the system of more oil than the pump can create .I dont have the exact pressure for priority on this model but it should be around 1700 psi .If pressure is below this it can cause your steering problems .When you put your gauge at priority you got standby pressure because you eliminated the internal leak . This should also make 3 point and steering work much better . You might think about dropping standby before it blows another seal. Your test for standby pressure was most likely correct the pump just couldnt pump enough oil to keep up with leak in the loader valve .

 

[Tx Jim]

I overlooked the statement about gauge reading 3000 psi & I agree with Gene that the pressure needs to be lowered immediately before operating tractor or seals will most likely BLOW. Is your tractors serial number below or above 045199??? 1020 with SN below 045199 has open center steering.[/url]

 

[mb1020]

Thanks everyone. Ok let me answer a few questions.

late model serial # post 45199. no seperate power steering pump. Just pulled the whole thing apart so I'm pretty familiar with it. I spent a lot of time on here researching before I tackled that project.

JD 143 loader (not sure open or closed)

In the picture you can see the plumbing of the priority valve. loader line removed and gauge installed at rear of valve. Loader line is in the bucket. Not sure if this is an accurate reading with the loader line open?? 3000 PSI and seemed to be climbing. I did it fast, because I noticed it was filling the bucket, but I may have cracked the valve and the loader probably fell some filling the bucket?? I was worried the 3000 psi. gauge might pop.

The second pic is the pump housing showing the port at top center which i tapped to get the 1000/1100 reading. which is what the IT book said to do.
8 piston non splined pump. I rebuilt the original pump with all new seals (put it back together with a slightly worn shaft and it leaked like a sieve). replaced the pump with a reman but never checked the pump pressure.

As I said, after making the first check on the pump housing, I cranked up the stroke valve maybe 1.5 turns. How much difference in pressure would a turn or half turn make?

I will turn this back down. My plan right now is to rehook up the loader and put a quick coupler on the gauge. I will then check the pressure with the loader disconnected and see if steering improves. Lastly I will port the return line to the fill hole and check for fluid seepage with the loader valve in neutral.

Internal leaks are totally possible. When we removed the housing with the planetary for the high/low, we found the housing was also cracked and damaged internally. The replacement housing should have resolved this but there could be other problems in the transmission case. We originally split the tractor to check the low pressure trans pump, however that appeared to be in good working order with no signs of wear. Unfortunately, we put it back together with the rear end of the unknown parts tractor so I do not know the exact status of the pump currently in the machine. After this fix the hydraulics worked better for a little while ( more down pressure) but then the steering got worse.

I pulled the steering because someone suggested bad seals in the valve might be causing the problems. (steering locks and worse pulls to right.)
:x However this made little difference.
The loader valve makes a lot of sense because it is the only variable that has not changed. Even the priority valve was switched out when the new rear end was put on.

Sorry the pics are turned sideways not sure why they uploaded that way, they are right on my computer??

 

[Tx Jim]

To determine if FEL control valve is OC or CC reconnect pressure hose then disconnect hyd fitting(green circle) & with both levers on FEL valve in neutral start engine & no oil should exit open hose.

 

[gene g]

If the hose in the white bucket is coming out of the filter housing , through loader valve and pumping oil into into bucket this will rob return circuit of oil needed to
supply main front pump and reduce out put . It can be plugged for testing purposes .

 

[JDEM]

If your tractor were in my shop- I would cap off the output on the pump so I know it cannot pump any flow. Then check stand-by
pressure and make sure it is around 2200 PSI. If it checks out OK this way, but drops once you hook it back into the system -
then you know you have a big internal leak somewhere.

When Deere tractors have the bigger 2.4 or 3 cube USA splined pumps an get internal leaks - the starters tend to burn up
because the engine crank over so hard. With the tiny .7 or 1.4 German pumps - sometimes even with a leak the starter can
still crank pretty well.

 

[mb1020]

There is a second (return?) hose going to a port right near the fill hole on the back of the transmission. If I remember right it comes off the left side of the loader valve just above the return going to the filter housing. Is that a filter bypass? If so what do I do with that hose to check it?

 

[Tx Jim]

Correct ""closed center hyd hose attachment"" for FEL control valve to tractor only requires 2(two) hoses which are pressure & return. If your tractor loader valve has 3(three) hoses attached from tractor to the control valve it attached incorrectly. Sounds as if someone installed an open-center controlled loader on a closed center tractor. See photo below that shows open-center system.

 

[mb1020]

Thanks guys. I really appreciate all the help.
So if the loader is open center, how would I check to see if the valve is operating properly? If my understanding is correct, oil is always flowing through the third line back to the transmission?

I'm going to disconnect the pressure line today and see if that helps the steering, ect.
Also someone suggested disconnecting the return line to the filter to check for leakage in neutral. But not sure if that is possible with open center?

If valve is bad... Can I replace it with a closed center valve and do away with the open center hose all together? If so does anyone have a suggestion on a good valve for an old used tractor that won't break the bank?

Apparently there were at least three different valves used on the loader, not really 100% sure which one I have.

 

[Tx Jim]

mb1020
You can disconnect return hose on open or closed center frt end loader valve then start engine with no ill affects to determine if valve is OC or CC. As I previously stated there's no good reason for FEL valve to have 2(two) return oil hoses on a JD 1020. If your tractor has 2 return hoses then aim both hoses with open ends in a bucket & if oil comes out of either or both hoses with levers in neutral with engine running you have located part of your tractors hyd problems. If oil comes out of return hose as I think it will you need to install a CC plug(green arrow) with correct seal(key 10).

 

[mb1020]

So I turned down the pressure a bit. Haven't rechecked it to see where it's at.
When disconnected, oil flows out the hose coming from the side port of the valve, which is plumbed to the filter housing, no oil flows from the other hose unless the valve is cracked.

However, the oil slowed to almost a stop after a few seconds. I was getting a bit low on oil so I turned it off. But I thought it might also be starving for oil. The 1st pic is of the steel supply hoses next to the brake. They were pretty crushed when I got the tractor, but the the hydraulics seemed to work so I left them. I have a replacement for the pipe going to the oil cooler, but not the one going to the pump. It was damaged in the tractor split operation. 2nd pic. Is it possible to replace these lines with rubber? They have a weird fitting on the end that slides in the case.
Could this cause the problems?

Also I tried the steering with the loader disconnected. There was minor improvement but nothing to really brag about.

 

[gene g]

Mark If you are using the line in the picture it would probably be a good idea to replace it or repair it . I have not tryed to replace it with a rubber hose, it mite
be possible . I was always told repair all known problems first . Did you look at suction screen , and replace hyd filter while you were doing trans. swap .You know JDEM
had a great way to check for internal problems with high pressure side of hyd. system.

 

[Bob]

IIRC, if steering pulls to one side there's a problem in the power steering gear... IIRC, if you get far enough into the valve section you have to keep track of shims as used/have special tools or procedures to select shims.

I would bet on an issue somewhere in that valve area, in the upper part of the guts of the power steering gear.

You surely aren't operating it with the cover/RH bearing missing from the steering shaft, are you?

 

[buickanddeere]

As previously stated. Stop that open centre operation with the oil flowing through that 3rd line directly into the transmission case.
Oil should only flow from the loader valves and back into the tractor filter housing. When the loader control valve is operated to move the loader.
The previous tinkerer who cobbled up the 3rd line mess needs a good swift kick on the backside.

 

[mb1020]

So if I understand correctly... cap off the output at the pump, then check pressure off the pump directly using the port on top opposite the destroke valve?

 

[mb1020]

The first pic is the working tractor. the second pic is the spare part tractor. The lines are hard to see but definitely crushed.

 

[mb1020]

Bob, Yes that's what I thought about the steering. But here is what I did: I have 2 pretty much identical machines. Before ripping apart the steering on the running tractor, I tore out the one on the parts tractor, replaced ALL the seals, cleaned the valves, one was sticking a bit, and installed it on the running tractor. I had the other valve set as a guide, and installed everything the same as I took it out.
When I tested it, the steering operated slightly better, but stilled pulled to the right as soon as I let go of the wheel, moving or not. this was the same symptom I had before switching out and rebuilding the entire valve assembly. I guess it's possible that both machines had the same exact problem but it seems a bit unlikely. and No the cover is back on the tractor.

 

[gene g]

You can put the gauge directly on out put end of an open center pump . The pump will destroke and stop pumping when it hits standby pressure . You can then adjust to
correct pressure . Then reconnect pressure line. If pressure drops you know you have an internal leak on the high pressure side. In loader, 3point , steering ,or
selective control. You will then be able to eliminate one at a time to find your problems .When you resealed steering and replace orings did you remove the housing or just the valves and shaft .

 

[buickanddeere]

A wee slip there, and I'll admit I have done worse. Closed centre destroys, the open centre lifts the relief valve if dead headed .....if the relief valve is between the pump and the dead head.

 

[gene g]

SORRY I said open center pump my mistake I should have said closed center pump . My mistake my proof reading needs some help.

 

[Tx Jim]

(quoted from post at 11:03:33 12/01/17)
IIRC, if steering pulls to one side there's a problem in the power steering gear... IIRC, if you get far enough into the valve section you have to keep track of shims as used/have special tools or procedures to select shims.

I would bet on an issue somewhere in that valve area, in the upper part of the guts of the power steering gear.

I agree with Bob in that problem with steering should be in steering housing assembly.

BUT 1st thing you need to do is get hyd loader control valve repaired or replaced so no oil exits return hose when valve is in neutral.

 

[buickanddeere]

(quoted from post at 00:55:41 12/02/17)
A wee slip there, and I'll admit I have done worse. Closed centre destroys, the open centre lifts the relief valve if dead headed .....if the relief valve is between the pump and the dead head.

D@mmed Spell Checker............" De-Stroked" not "destroyed".

 

[mb1020]

Jim, where did you get the image of the valve you mentioned with the plug. I can't find one like that on JDparts. None of the sectional drawings seem to match my loader. They all look like closed center. Perhaps someone replaced the valve? Your image looks right, but I need part numbers.
The image below is the closest one I found but the plug looks wrong.

I'm going to replace the supply lines first, because if the pump is not getting enough oil flow there is no point in checking anything else.

On the steering, I pulled everything apart, completely stripped it down. I replaced one shim that was worn with one off the the spare steering valve. No signs of wear otherwise. The only thing that may be a problem is one of the tiny valves was not operating very well. I cleaned it and would guess it was at 90% when I put it back in. That was the upper valve. I would have just swapped the valve but the other spare one was much worse. I should have seen a major improvement after the rebuild, even if the new valve was not 100%.

 

[Tx Jim]

You can find schematic for convertible(OC to CC & vice versa) valve in JD parts catalog for model 37,48 & 145 loaders plus probably more catalogs.

On steering if one or more of the 6 large o-rings is leaking it can make hyd's do strange things especially heat up & cause frt pump to cavitate.

 

[mb1020]

thanks Jim.

Yeah all the orings got switched out, but it could be possible one got out of place when the valve assembly was inserted in the housing. Not exactly easy to get back together.

Just doesn't make sense to me the new (different) valve would have the exact same issue as the old one I removed.

I've had issues for a long time with the steering locking when stepping on the brakes a lot especially when using the bucket, however this new problem of the steering pulling right started not long after the last time we split the tractor. The tractor is also much easier to steer while moving then when stopped. Most of the time I have no power steering to the left, and as soon as you let go of the wheel it pulls all the way right every time.

 

[Tx Jim]

Applying brakes on a JD utility tractor of this era should have little to no affect on operation of hyd's because only thing hyd's do is keep brake valve reservoir full by means of trans pump pressure.

 

[mb1020]

Gene, yes the steering housing was swapped as well. I looked at it pretty carefully and couldn't see any obvious flaws.

 

[mb1020]

Ok I think I may have just stumbled on something but I need someone to confirm this.

Sorry again for the pics, they are upside down. i tried turning them on my computer, even turned them upside down, but they still upload wrong...oh well.

These are pics of the parts tractor with brake and steel oil lines removed. Am I correct that the line from the oil cooler attaches to the outermost (passenger/right side) hole which feeds directly into the brake cavity(reservoir?)? If so then my mechanic swapped the lines and the pump is probably drawing from the brake.
The innermost connection being the output from the trans pump to the hydraulic pump?

 

[gene g]

The reason I ask is because I had a remanufactured valve do the one way creep and I found the problem in the lower part of the housing . Im sorry I cant give the exact
detail on the repair . I do not remember its been several years ago . I remember that I had to remove the entire valve to find the problem and make the repair . I was
not happy with the DO OVER when it was a mistake at remanufacture . I hate old age . I will look at some of my books tomorrow and see if will jog some old details .

 

[gene g]

I dont know which line goes where . But some small utility tractors had a check ball in one line . A parts book would answer what models used the check ball

 

[mb1020]

(quoted from post at 12:17:51 12/05/17) I dont know which line goes where . But some small utility tractors had a check ball in one line . A parts book would answer what models used the check ball

Yes the line going to the pump has a check valve.

 

[gene g]

Some times you can see a mark on the end of the lines at the trans. end where the keeper was holding them into the case .