JD 2720 Hydraulic Issues

[smashedtoe]

Hi.

I have an interesting one which I am suspecting with get one of two responses:

• Crickets
• You should talk to the guy who changed the charge pump

Here is why I am here typing to you today.

I replaced the charge pump in my JD 2720 as I was experiencing some steering related issues and the PTO quick working. Ended up finding the inner charge pump rotor broken and a sheared key on the shaft; pump changed with no issues.

Start the tractor, PTO works amazingly however, the steering is still almost non-responsive and there appears to be some air in the lines. Here is where things get a little weird; when I engage the PTO the steering improves (not perfect) but the hydrostatic drive whines more.

I am suspecting a relief valve and praying for a miracle.

Oil levels fine, but when I loosen the test port on top of the charge pump the oil is filled with plenty of little bubbles and "appears foamy" which settles down to clear oil after a few moments. I loosen another line and air seems to "burp" out, but I dont know if this is normal and I should continue to run the tractor/add oil to purge any air?

Any help would truly be appreciated.

Thanks

Jeff

 

[beenthere]

Seems you have a couple years of problems that may, or may not include this pump. How do they all tie together, or do they not at all ??
Feel sorry for your problem, but wonder if there is a common thread here that is important to a solution for you. Hang in there.

John Deere 2720 - Zero Hydraulics, Zero 3-Point Hitch, Zero Answers...

Hello all. First, my apologies if I am posting this in the incorrect location. I have a John Deere 2720 with 419 hours. Approximately 3 months ago i noticed the hydraulics (loader, snow blower) and 3-point hitch were moving much slower than usual so I did what every other newbie would do...

www.tractorbynet.com

John Deere 2720 - Kanzaki Hydraulic Pump

Hello all, I am looking for a rebuild kit for the Kanzaki PW1-D-8A hydraulic pump off my John Deere 2720 utility tractor. Interanal rubber gasket/seal (?) is broken and I can not justify spending $700 CAD on a pump when the aforementioned seal is the issue. Anyone here know where I can...

www.tractorbynet.com

John Deere 2720 Hydraulic Pump Seal Issues

Good Day all. I have a John Deere 2720 compact tractor which I just repaired by installing a new hydraulic pump. Everything seemed fine, but for some reason the shaft seal keeps blowing and leaking hydraulic oil into the engine. Any suggestions or recommendations as to what would cause...

www.tractorbynet.com

John Deere 2720 No PT0 No Power Steering....No Clue

Hello once again friends. Okay I am faced with another issue with my JD 2720 and I am looking for some advice.....and no, not the advice which suggests a different colour tractor, etc. This past winter during an extreme cold snap (-42C) my son wanted to be helpful and clear some snow. He...

www.tractorbynet.com

 

[seville009]

Make sure that the hydraulic filters are tight; not letting a little bit of air in. They probably are fine, but you never know…..

 

[smashedtoe]

Seems you have a couple years of problems that may, or may not include this pump. How do they all tie together, or do they not at all ??
Feel sorry for your problem, but wonder if there is a common thread here that is important to a solution for you. Hang in there.

John Deere 2720 - Zero Hydraulics, Zero 3-Point Hitch, Zero Answers...

Hello all. First, my apologies if I am posting this in the incorrect location. I have a John Deere 2720 with 419 hours. Approximately 3 months ago i noticed the hydraulics (loader, snow blower) and 3-point hitch were moving much slower than usual so I did what every other newbie would do...

www.tractorbynet.com

John Deere 2720 - Kanzaki Hydraulic Pump

Hello all, I am looking for a rebuild kit for the Kanzaki PW1-D-8A hydraulic pump off my John Deere 2720 utility tractor. Interanal rubber gasket/seal (?) is broken and I can not justify spending $700 CAD on a pump when the aforementioned seal is the issue. Anyone here know where I can...

www.tractorbynet.com

John Deere 2720 Hydraulic Pump Seal Issues

Good Day all. I have a John Deere 2720 compact tractor which I just repaired by installing a new hydraulic pump. Everything seemed fine, but for some reason the shaft seal keeps blowing and leaking hydraulic oil into the engine. Any suggestions or recommendations as to what would cause...

www.tractorbynet.com

John Deere 2720 No PT0 No Power Steering....No Clue

Hello once again friends. Okay I am faced with another issue with my JD 2720 and I am looking for some advice.....and no, not the advice which suggests a different colour tractor, etc. This past winter during an extreme cold snap (-42C) my son wanted to be helpful and clear some snow. He...

www.tractorbynet.com

This really has been a frustrating one with this tractor; oddly enough so low hours on it (I purchased it brand new so I know the hour meter is bona fide).

I had a fella call me today and thought maybe some debris from the sheared charge pump key is caught in a relief valve which is a little scary as i would have no idea how to clear that out. Also had some great suggestions to check tomorrow morning; sump screen, loose/plugged filter or plugged orifice.

Needless to say, I went to JD today and eyed up a new 2038R but my stubborn side says "hang in there Jeff....the solution is right under your nose."

I am going to buy a pressure gauge tomorrow as well and see what the pressure is testing at....for my own sanity.

Time for this good run of bad luck to run out.

Thanks to you all for your support, suggestions and ideas. You have no idea just how grateful I am for this forum.

 

[smashedtoe]

Seems you have a couple years of problems that may, or may not include this pump. How do they all tie together, or do they not at all ??
Feel sorry for your problem, but wonder if there is a common thread here that is important to a solution for you. Hang in there.

John Deere 2720 - Zero Hydraulics, Zero 3-Point Hitch, Zero Answers...

Hello all. First, my apologies if I am posting this in the incorrect location. I have a John Deere 2720 with 419 hours. Approximately 3 months ago i noticed the hydraulics (loader, snow blower) and 3-point hitch were moving much slower than usual so I did what every other newbie would do...

www.tractorbynet.com

John Deere 2720 - Kanzaki Hydraulic Pump

Hello all, I am looking for a rebuild kit for the Kanzaki PW1-D-8A hydraulic pump off my John Deere 2720 utility tractor. Interanal rubber gasket/seal (?) is broken and I can not justify spending $700 CAD on a pump when the aforementioned seal is the issue. Anyone here know where I can...

www.tractorbynet.com

John Deere 2720 Hydraulic Pump Seal Issues

Good Day all. I have a John Deere 2720 compact tractor which I just repaired by installing a new hydraulic pump. Everything seemed fine, but for some reason the shaft seal keeps blowing and leaking hydraulic oil into the engine. Any suggestions or recommendations as to what would cause...

www.tractorbynet.com

John Deere 2720 No PT0 No Power Steering....No Clue

Hello once again friends. Okay I am faced with another issue with my JD 2720 and I am looking for some advice.....and no, not the advice which suggests a different colour tractor, etc. This past winter during an extreme cold snap (-42C) my son wanted to be helpful and clear some snow. He...

www.tractorbynet.com

Oh, I nearly forgot to respond beenthere...

So the first two hydraulic pump postings are not related to the latter two. Albeit these are both odd scenarios as the JD dealership Parts Depts. have no record of ordering these parts for anyone in the past...heh heh heh....definitely not the external pump (thank you to Yanmar for that).

I have grown up on JD and continue to use these machines every day....maybe this 2720 should have been painted Lemon Yellow. I dont know but I do know I am not going down without a fight.

 

[oldnslo]

A couple of questions come to mind.
1) What caused the original charge pump to fail. Did it seize or get scored generating debris that went into the system.

2) Is steering, PTO and charge all from same pump? Suspect yes from symptoms

Do you have service manual with hydraulic schematic? If yes can you please post it since that could help us arm chair mechanics determine items to check.

Deere normally is good about having test ports for doing diagnostic work.

 

[smashedtoe]

Hello oldnslo (love that name!)...

I believe what caused the pump to fail originally was my son started the tractor during extremely cold weather without allowing a warm up period, placed it in High Range and proceeded to back out of the cold storage shop. Tractor reversed about eight feet and quit moving (suspecting this is when the key sheared on the shaft/breaking inner rotor on charge pump).

Yes, the steering and PTO function off the charge pump; implements work off an external, engine mount pump.

I do have the JD Technical Manual and have attached some pages as requested.

Thank you so much!!

 

[oldnslo]

Smashedtoe ( been there done that also)
in looking at schematic valve O the charge regulator is what also supplies excess oil to PTO circuit. I would start by checking your charge pressure since you stated engaging PTO seems to help steering but now HST whines. Charge is critical so you don’t damage the very expensive HST.

next I would check steering pressure since should be secondary pressure compared to charge.

Cold oil shouldn’t cause the pump to shear drive if system is designed properly. That being said my Branson blew the HST filter from cold oil and system not being designed to allow cold oil flow so definitely could be the cause.

admire your attitude of stubbornness will overcome common sense

 

[smashedtoe]

This is where I begin to draw a blank as i have no idea where to find "Valve O" or where to place my pressure gauge to test? Come on Google!! What you are saying does make sense though oldnslo.

I believe I know which port to tie into to check the steering pressure....read that in the technical manual. As soon as the Traeger has dinner ready and my belly is full I will venture back into the shop and see what the gauge tells me.

Thank you so much for the feedback!

 

[oldnslo]

I am surprised that the service manual does not have a trouble shooting or diagnostic section for the HST and steering. Is there another section in the manual for diagnostics?
Schematic shows what I suspect is a test port for pump pressure but the section you posted certainly does not state where it is.

As a point of reference valve O is drawn as pressure reducing valve vs relief valve but again where is it and where is test port for charge vs steering vs PTO?