New owner 4020 LPG questions

Rapidrob

Member
I was given a 4020 LPG Syncro tractor today. It has been in the desert since it was sold.
It is in very good condition and has almost new rear tires.
The owner had it for sale for many years with no buyers due to bad propane leak and cost of propane.
I took the cover off of the engine and found the problem was a cross threaded T-fitting in the gas solenoid valve. An easy fix.
The tractor has not been run for eight years.
I pulled the spark plugs and squirted oil into the cylinders and turned the engine over. Every thing is free to move. No rot or other problems noted.
I re-filled the coolant.
The oil is clean buy I'd like to replace it. What filter does it take? Is the filter behind the four bolt plate on the left side,rear of the engine?
What oil do you recommend to use? it gets 100 here in the summer...-15 in the winter.
The tractor will only be used to pull a plow to maintain a dirt mountain road.
I found a Youtube vid on how to drive the tractor but not how to start it.
There are two valves going to the LPG tank. Not sure which valve does what? Left/Right
The front axle is set to max width. This will not work well on my tight dirt road which is very steep with no areas to turn around. If I close in the axle to the thinnest width will this allow me to skid steer and turn the tractor around in a smaller radius?
I have no manuals on this tractor,just some info I found on the net.
Any info is appreciated.
Thank you.
 
With your unfamiliarity with a 4020 tractor, particularly an LP model, it is extremely important to obtain an owner's manual. I suspect there will be others who will agree with me. Now, I do not have an owner's manual for every tractor I have, but I have manuals for most of them. I also have models of tractor that are similar to one another, too. I wouldn't have the slightest idea on the start up and operation of an LP burning tractor, as mine are either gasoline or diesel powered. Perhaps you will get a response from someone who can at least help get you and your tractor started.
 
I'll second the motion to get you a manual. It will assist you more than you will know. If you were given the tractor, then a few bucks spent on ebay (or elsewhere) for a manual will be a good investment.

As for some of your questions- I believe the Deere number for the filter is AR26350 (going from memory here). It is indeed behind the 4 bolt cover on the side of the pan.

Narrowing the width of the front end will not reduce the turning radius any more than the width narrowed. You can use the brake to assist in making a sharper turn.

If your tractor was a diesel, I'd recommend a good brand of 15w40. Not sure on a gas one.

Good luck. And spring for the manual.
 
You start these engines on vapor and when warm
switch to liquid! The engine oil can bevaried. I used
a diesel oil in mine to clean out the sludge in the
mistreated engine, then went to a low ash oil for
continuous running. It's been a long time since I
started a Deere on lpg. Our Minneapolis moline lpg
tractors has a primer on the heat exchanger /
converter to help the engine start after being parked
for a time period! Some are solinoid operated but
just can't remember on a Deere!
 

IIRC oil for LPG engines is suppose to be "low ash" oil. Ditto on engine oil filter part number connie minnie(AR26350). Engine oil filter is in engine pan held by cap with 4 bolts.
 
An alternate for the AR26350 oil filter is NAPA Gold 1242.

A gasket comes with the NAPA filter if the 4020 uses a gasket. The AR46350 filter does not, you have
to buy it separately, A519R.
 
IIRC the A519R only fits the 2 cyl. the 4020 takes a different gasket. NAPA one should come with both styles.
 
A narrow front (roll-a-matic ) will allow the tractor to turn almost in its own tracks with the brake applied .
 
Thank you for the replies so far.
I found a manual on line and stayed up until the wee hours reading it.
I noticed that JD recommends their "Special Oil" for the hydraulics.
Is it really needed? Tractor Supply sells a generic oil. Can it be used?
The Propane delivery guy should be here today and I hope to get the tractor started. Purging air does not look hard to do.
No one has seen the ignition key for years. I will have to jump the wires to fire it up.
So far I have checked everything that needs to be checked and it looks like it should fire right up.
I do not know if the Idiot Lights on the panel work. Someone cobbled in an direct engine oil pressure gauge so I should have at least an indication that the pump is working.
I'll let you know how it goes.
 
DO NOT use generic hyd. oil in these or brake lining failure is sure to happen ! Might be too late ?
Use ONLY JD hy-gard to be safe.
 
If you need help with the propane aspect of
it, I can help. Plus, as you said, your
propane delivery guy will probably be really
savvy too. Any questions, you can email me,
email is open. Good luck. Hugh
 
If the switch takes a two pronged key, a flat blade screwdriver works to turn the ignition switch on those tractors. A replacement keys is also available many places, they were not coded.

Use the "special oil".
 
I got up a dawn and made a key out of two Allen wrenches and a piece of brass plate. works well.
The propane guy showed up at 1100 AM and filled the 55 gallon tank.
I purged all the air out of the gas system and tried to start the engine. No start. Good speed cranking,sometimes a fire but but no go.
I tried the two valves independent of each other,then together it ran for two seconds and stopped.
I noticed the propane gas solenoid strainer leaks badly at the two half joint AND at the magnetic coil????
This part will need to be replaced as using a gasket sealer did not help much,a little yes,but the 250 PSI Propane was just too much for the old casting.
OK, back to starting. The high pressure gas to 14" of Water Column Gasafier(?) had a center button that when pushed would flood the air filter with propane. No instructions in the manual on this.
I found this quite by just playing around.
The air intake flooded with gas did the trick and I hit the starter and on the third ten second cranking the engine fired.
A shower of rust from the exhaust and a cloud of desert dust being drawn through the radiator covered the tractor.
The idle was set too high at 1,000 RPM,but the engine ran very smoothly.
Before the tractor was moved I had to add seven gallons of JD hydraulic oil. ( this tractor sat for 8 years remember)
Oil pressure gauge was showing 40 PSI.
The temp after 20 minutes was normal via gauge.
I did a walk around to check for leaks.
The oil pressure sending switch to the idiot light is leaking around the switch,not the threads. It will need to be replaced.
The Generator is NOT producing 12+ volts. I'm getting 2.5 VDC at 1500 RPM. Something is not right. The voltage regulator looks new inside. I burnished the points,no help.
All the terminals are clean. Original wiring in good shape,not great.
Four of five head lights I got to work. The rear head light is only getting 8 VDC. The quick disconnects could be bad.
All of the grounds were poor. Lots of work to get them to show less than two Ohms resistance.
I took the tractor for a test drive.
Right off the bat I noticed that the Synchronous transmission did not want to go into the gears I want it to go into.
I had to really fight the lever to find any Reverse gear it would engage. Linkage is tight on the transmission,underneath the tractor.
Letting the clutch out at 1500 rpm only produced the rear end to jump upward. The brakes were not releasing.
After driving forward a few feet then backward the same things seemed free up.
The tractor was on a steep incline,nose down. We blocked the wheels if the tractor stalled and tried to drift down the mountain.
I used the foot accelerator to boost the engine rpm just a little and tried to back the tractor again. This time after a few hard bounces,the tractor moved and I was able to back it to level ground.
Once I was able to get it into park ( it was never in park) I was free to try the hydraulics. Every thing worked well with no leaks.
Now to try the steering from stop to stop.
The wheels would turn to the left all of the way,but not fully to the right. Also there was a banging sound coming from the front of the tractor,like a coupling was striking a cowling.

After the engine came up to Normal Temp I tracked down the knocking sound. It seems to be coming from the Power Steering??? the large device with the Pittman Arm at the very front of the tractor.
The wheels are now moving fully in both directions. The noise is still there. No idea just what is causing it in the Power Steering.
It was time for a test ride on level ground,dirt road.
The transmission is still not going into the gear I want it to be in but I was able to get it into 3 and 7 and the third notch down reverse.
The tractor moved with no real effort and tracked well with no play in the steering. I tried the brakes tied together and they are there,not great but there.
I unhooked the brakes and tried a locked wheel turn. The brakes on what ever side were not happy and really made a very loud noise . The tractor did do a very tight turn which is needed on my mountain road. The brakes will need to be used a lot to get them normal again. Sitting all these years has not helped.
The tractor looks like it will fill the bill to keep my mountain road usable year round.
I will need to replace:
Oil switch for idiot light.
Propane strainer/solenoid
perhaps the generator
 
Mike,
You're absolutely right. I should have said the NAPA filter comes with two gaskets, with one of them for the 3010/3020 and 4010/4020. Mentioning the A519R in this case was my mistake.
 

Knocking noise up front is more than likely worn frt hyd pump pump drive coupling or bushings. Also be sure coupling is tight on pump shaft.
4 ea-R45822 Bushing - ADD 2.43 USD 9.72 USD

40526.jpg
 
Thank you for the diagram. I used a sound transducer and the noise is at the far front of the coupling as it enters the pump.
**************
After looking for a replacement fuel strainer, I will try to seal it first.
I have not found a rebuild/seal kit for the device yet.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top