Prime the Hydraulic pump

[sshort4014]

I have a JD 5210 that I recently changed the hydraulic oil and filter. My son apparently started the tractor before I had refilled the reservoir with fluid. Consequently this evacuated the hydraulic pump and now that I have filled it with fluid the pump will not pick up. How do I re-prime the pump? Any help would be appreciated.

 

[Brimstone10x]

There maybe othe ways but I would remove suction line from the top of the pumps and pour some hyd oil in maybe crank the engine over for a second and pour some more in and reconect the suction line and it should be fine.the pumps are mounted on the engine on the rh side . clean off any debris in the area first.

 

[JD5210]

I reviewed the 5210 technical manual to include the section that speaks to removing and installing the hydraulic pump and there is no mention of a need to re-prime the pump. The pump itself creates the suction, lines coming off the top of the tandem pump are pressure lines. The line coming from the filter is the suction line.

I have replaced the hydraulic fluid and filter and cleaned the pickup screen on my 5210. While I did not startup the tractor no re-priming was needed.

The following is from the tech manual.
THEORY OF OPERATION:
The hydraulic pump assembly contains two pumps, each of different displacements. The 20-cc hydraulic pump supplies oil for the rockshaft and other tractor hydraulics. The 12-cc pump supplies oil for the steering system and transmission lubrication. Both pumps operate identically and use a positive-displacement, external-gear design that moves a set volume of fluid with each revolution. Output volume changes only when the speed of the pump changes. The engine drives the hydraulic pumps from the camshaft drive gear. As the pump gears (C) rotate, they continuously move in and out of mesh with each other. When the gears separate, a vacuum develops which draws oil into the pump inlet (A). The oil continues to move with the gears as they turn. As the gears come back into mesh, they form a seal which prevents oil from returning to the pump inlet. Further meshing forces oil out the pump outlet (D) and into the hydraulic system. This cycle repeats continuously as long as the pump turns.

The following is the URL痴 to the 5210 operator manual.

//manuals.deere.com/omview/OMRE71736_19/?tM=
The following are some URL痴 from the John Deere web-site you may find informative.
//www.deere.com/en_US/ag/servicesupport/tips/augusta/5000/instrpanelfog.html
//www.deere.com/en_US/ag/servicesupport/tips/augusta/5000/leakfuelcap.html
//www.deere.com/en_US/ag/servicesupport/tips/augusta/5000/backlash.html
//www.deere.com/en_US/ag/servicesupport/tips/augusta/5000/modelyear.html

 

[sshort4014]

Thanks for the info. I'm pretty sure that the pump is working - when the engine is running it builds pressure in the resevoir. I can here air escaping from the hyd. oil dipstick. The rockshaft will also raise and lower with no weight on it. No power steering and the FEL will not work. It was working before the fluid and filter were replaced.

 

[JD5210]

Not being an expert in this area, I need some other info. Was there a reason you changed the hydraulic fluid and filter other then routine maintenance? Did you clean the pick-up screen (transmission oil strainer) how did it look and did you put it back in correctly? If I recall correctly it did not seem that hard to put it in backwards. I have included the URL to JD parts, if you do not have it, to see how the pickup screen looks. You might consider loosing the filter a little to see, if some fluid leaks out. This would tell you if the fluid is getting that far. If you are concerned about damaging the seal, you could loosen the pickup screen bolts. I would not loosen anything on the pressure side. For what it is worth there is nothing in the tech manual about bleeding.

The flow is fairly simply. The engine drives the hydraulic pump from the camshaft drive gear. As the hydraulic pump turns, a low-pressure area develops in the suction line. Oil then moves from the transmission case through mesh filter and 25-micron filter canister, then on through suction line to the inlet side of the hydraulic pumps.

John Deere - Parts Catalog

 

[jd110]

How long has the engine been run with no oil in the transmission? If the pump is run dry too long, it can damage the pump. A pump in good condition should not need priming. A worn pump can still operate satisfactorily though. I would remove the top fittings on the pump and fill those ports with oil. I then would remove the hose from the bottom of the pump and pour some oil in there - you probably won't be able to fill it since the oil will siphon through the filter and back to the transmission. Also you could overfill the transmission to get the oil level closer to the pump level. You could also put the front of the tractor down hill to try to get the flow to the pump started. Or jack up the rear of the tractor.
I would also double check the oring on the filter. If the oring gets cut, the pump can suck air.

 

[sshort4014]

Thanks to all for the suggestions - I will investigate further and try these recommendations this weekend. I will let you know what I find out.

 

[LaVerne]

Here's your answer. If your pump is not damaged this will work.
Take the pump outlet fittings off Take a shop rag and an air gun. Put the air gun in the fill port, and wrap the shop rag around it real tight to make a seal. Blow all the air you can into the case until oil comes out the pump fittings. Have an assistant immediately reassemble the fittings on the pump while oil is still leaking out. This pushes oil into the pump. immediately start the tractor when the fittings are tight. You can safely pressurize the tank to 5 PSI, but don't make a contest out of it. You need clean dry air. And in the future when you drop oil, add it back right away as soon as you can. This can happen easily with worn pumps, or if the sump is left dry for a long time. If you look in the port, and you see aluminum filings DONT START IT. the pump is trashed, and you will just ruin your steering and rockshaft valve if you try to use it. Get a new one - the old one will never work if there's trash in it from running it dry.

 

[Dave Pert]

Here's your answer. If your pump is not damaged this will work.
Take the pump outlet fittings off Take a shop rag and an air gun. Put the air gun in the fill port, and wrap the shop rag around it real tight to make a seal. Blow all the air you can into the case until oil comes out the pump fittings. Have an assistant immediately reassemble the fittings on the pump while oil is still leaking out. This pushes oil into the pump. immediately start the tractor when the fittings are tight. You can safely pressurize the tank to 5 PSI, but don't make a contest out of it. You need clean dry air. And in the future when you drop oil, add it back right away as soon as you can. This can happen easily with worn pumps, or if the sump is left dry for a long time. If you look in the port, and you see aluminum filings DONT START IT. the pump is trashed, and you will just ruin your steering and rockshaft valve if you try to use it. Get a new one - the old one will never work if there's trash in it from running it dry.

+1 on this. I don't know how many hours or days this just saved me but worked like a charm. Oil on my hinomoto had been dropped for a couple of weeks and linkage didn't function upon recommissioning.