11-17-2012, 03:04 AM
JD 1020 hydraulics problems
I think this is the righ forum for this size tractor. I have hydraulic problems with my JD 1020. I pretty much know the hydraulic system. No reverser, std pto with the side lever.
Tractor sat for 5 years. Its a gas model. No loader. Cranked it up, hydraulics slow but started working. Power steering worked, brakes worked. Hyd. Dip stick indicated hyd. oil ok before start up, fluid clean. After start up, I got milky oil.
Changed out filter, checked suction filter in transmission and pump. New oil, no hydraulics. Ran at high idle, did not pick up. Checked flow from transmission at hyd header tank, lots of flow. No hydraulics at all. Let sit over night, same thing.
Was working, now it is not working. Something changed or stuck.
Have not checked the pressure control valve located just behind the filter. Had some water in the brake lines I should note. Bleeding the brakes fixed the brakes. Do not know how water got into system. tractor was under a good shelter.
11-17-2012 03:04 AM
11-18-2012, 03:39 AM
Water can accumulate from condensation in a tractor that has not been in use. Also a frequent area water can get in is around the shift lever boots. The boots get torn or cracked and allow rain water in.
The loss of hydraulics could be many things. Are all functions not working? No power steering, 3 point, or scv operation? The hydraulic pump coupling may have failed. The woodruff key could have sheared. The pistons in the pump could be stuck from lack of lubrication from water contamination. The stroke control valve in pump could be damaged.
11-18-2012, 01:02 PM
JD 1020 hydraulics problem
None of the hydraulics work now. Had everything when I first cranked it but the fluid was clear on the dipstick when I first cranked it. Got milky afterwards. Yes I have a cracked boot on one of the shifters. I will get that fixed. No pwr steering or 3 point. Coupler is ok, pump is turning.
Originally Posted by jd110
The tube nuts on the hi pressure line running back to the power steering and priority valve were frozen to the tubes. I finally got them to free up after connecting a vibrator to the lines and spraying PB blaster on them. Heat and tapping would not break them loose. The vibration worked like a charm. Now I can loosen them if need be to bleed or whatever.
I did not check the filter bypass valve when I changed the filter. Did not check the pressure relief valve for the transmission pump either.
Mine does not have the reverser system on it. Looking at the hydraulic schematic, I guess the output of the gear pump feeds directly to the charge port on the front pump. My front pump is a 8 piston type. I did check the suction screen in the front piston pump, it was clean. As I noted before, I had water in the brake lines running to the rear end. I disconnected them and let it drip out. I then bled the brakes and they seem to work fine now.
I guess I need to check the filter bypass valve and gear pump pressure relief valve. As for the piston pump, I see there is a pressure relief valve, and that poppet valve that seems to be used to set the system pressure in the neutral hydraulics position.
Any suggestions on the order of checking things? I have been cleaning up the electrical and have it all working correctly now. Neutral switch was bad and I fixed that also. It was jumped out. Bad bulb on the oil pressure light, bad circuit breaker, had to clean the ignition switch and light switch but both are working fine now. I have expertise with electrical and I am familiar with hydraulic systems as I worked on them for years in the plastics industry as a process Engineer. Just do not have any experience with tractor hydraulics.
I read the shop manual on the hydraulic system and was amazed at the number of adjustments needed to correctly balance the 3 point operation, system pressure and such. I am still studying the 3 point system and the load control shaft. Did not know about any of the draft adjustments.
Hoping something is just stuck open somewhere and the system will operate after I find it.
Suggestions welcome. I am just taking my time with it. Kind of getting attached to the tractor.
11-18-2012, 09:52 PM
JD 1020 Hydraulics problem
Originally Posted by gacannon
My son helped me to day to check a few things. We inspected the oil filter bypass valve. Looked clean and in good shape. Re-installed. Inspected the pressure control valve spool assy and it was clean and in good shape. Inspected the stroke valve assembly. It was clean in appeared in good shape. Set it back where it was before I took it out. Re-checked pump stroke valve filter, clean, no problems seen.
Then we performed the flow test on the return to transmission line from the top of the Hyd. header tank. This consisted of hooking a piece of pipe to the rubber hose and putting a TEE on it with a gate valve feeding down. The other end of the TEE had a pressure gauge. Test was for 1 gal flow in 10 seconds at 35 lbs. Tested ok, lots of flow. This tells me the transmission pump is pumping just fine and supplying charge pressure to the 8 piston front hyd. pump.
Finally, I disconnected the power steering feed line from the high pressure line feeding from the front pump. Absolutely nothing coming out of the pump.
The 8 piston hyd pump has charge pressure from the gear pump in the transmission. Nothing is coming out of the 8 piston pump.
With this information, can anyone chime in here and advise me.
For some reason or failure of a part, the piston pump will not pump any fluid into the out put chamber of the pump / hi pressure output line.
Also, The manual says the transmission oil pressure should be 100 to 140 PIS. If I turned the gate valve off, which dead headed the output line from the header tank, I got a 400 PSI reading on a know good gauge. Either the gear pump is putting out 400 PSI or the piston pump is charging the suction side of the pump!
This pressure of 400 PIS is not correct? Is this an indication of a failed inlet valve. Can a failure of one inlet valve cause zero system output pressure from the piston pump?
Just think the 400 pis pressure indication is indicative of what has failed. That header tank is not built for 400 PIS. Normally the outlet line is hooked to the sump in the transmission so no pressure can build at that point, but it sure did when I closed the gate valve on the test rig preventing flow into a bucket. That deadheaded the header tank and the pressure was 400 psi. I have not performed a gear pump pressure test. There is a pressure relief valve to regulate the charge pressure to 100 - 140 PIS according to the manual. Where did the 400 psi come from.
11-19-2012, 05:25 PM
JD 2010 hydraulic proble
Originally Posted by gacannon
I connected a 0-3000 psi gauge on the front piston pump as shown in the Deere tech manual. They call that pressure the standby pressure. I got 1500 PSI. I ran the SV out some and the pressure dropped off to 1000. Ran the SV all the way in and got maybe 1700 PSI. Tech manual says when standby pressure is 1500, nothing works. I guess that means the pump is not reaching the pressure necessary to unload the ouput check valves because there is nothing flowing in the high pressure output line of the piston pump, nothing.
I cleaned and inspected the SV. Nothing the eye can see anyway.
Pump gets noisier when the SV standby pressure is lowered and quieter when the pressure is raised. But max of 1700 PSI standby pressure.
Pump problem with seals or bad stroke valve?
Figure its one or the other.
11-19-2012, 05:46 PM
I'm just a beginner when it comes to hydraulics, but is there an internal high pressure relief valve that is leaking/broken spring that is by-passing the pressure before the output check valves?
Originally Posted by gacannon
Just my 2 cents.
2011 1026R/R4's -- H120 FEL/49" -- 260 BH/12" -- Bro-Tek Ripper -- Artillian Forks
11-20-2012, 04:05 AM
JD 1020 Hydraulics problem
Originally Posted by Tomfive
That is what I am thinking. As 1700 PSI is as high as I can get the standby pressure to go with the Stroke Valve all the way in. Something is leaking down the pressure internally and the pressure is not enough to even open the output valves. When I tested the charge pump (gear pump in transmission) the book called for disconnecting the return line from the hydraulic header tank and installing a tee with pressure gauge and gate valve. Test called for putting the tractor in PARK with clutch pressed. Then crank engine. Then release the clutch and adjust the gate valve to maintain 35 lbs pressure and measure 1 gallon flow into a bucket in 10 seconds. It passed this test, but when I closed the valve, the pressure went to 400 PSI. I opened it back up quick as 400 PSI on the header tank scared the crap out of me. Where did 400 PSI come from? Had to be the piston pump feeding back into the suction line. The pressure should not be over 140 PSI max from the gear pump.
I guess I am going to remove the pump and disassemble it to see what is wrong. Does not look like too big of a job. JD seems to have done a good job with the design on this tractor as far as working on it goes.
I have a operation scheduled in a week to remove my kidney and was hoping to get this thing going before then, but looks like that is not going to happen. I enjoy working on older machinery. Keeps my mind off cancer. I am getting attached to this old JD tractor.