BX25 Hydraulics not working correctly

[scrappin35]

Hello everyone, new to the forum and did a search to see if there was another problem consistent to mine but came up empty.

about a month ago I discovered a very small leak in one of my hoses that went to my loader. Before I could repair it my hydraulics started acting up.

My symptoms are that as long as the RPM's are below 2200 everything works fine. But if I hit the end of either the 3 point hitch travel on the way up, the top of the boom or bucket travel then everything stops working. I know that there's a release valve in play with the normal operation that kicks in when you reach these stop points, but some how that is now being triggered by my described symptoms and not releasing. The only way to get it to reset is to turn the tractor off and restart. I did a slow rev-up and again right about 2200 I can hear the pump/engine change and the hydraulics stop working.

• I've replace the leaking hose and do not see any additional leaks. I then made sure the system was topped off. (Didn't really need anything since not much leaked).
• Did a complete Hydraulic fluid change to include filter and suction screen cleaning. (screen was almost completely void of material.
• Removed the relief valve and checked for anything unusual in the spring or shims but nothing. I'm not sure how to service the valve and haven't seen any related video's info in internet searches.
• I've also disconnected the 4 Bucket lines to see if it was perhaps related to just the bucket but the 3 point hitch still acts up.

I believe it may still be the relief valve but not sure how to proceed. Any and all assistance is greatly appreciated.

 

[85Hokie]

Welcome to the Forum!

To me it sound like you are sucking air - thus the pressure can build and the relief valve will NOT kick out due to air being in the system.

" I discovered a very small leak in one of my hoses that went to my loader. Before I could repair it my hydraulics started acting up. "

which came first? Leak or problem? Problem come after the leak?

 

[scrappin35]

Welcome to the Forum!

To me it sound like you are sucking air - thus the pressure can build and the relief valve will NOT kick out due to air being in the system.

" I discovered a very small leak in one of my hoses that went to my loader. Before I could repair it my hydraulics started acting up. "

which came first? Leak or problem? Problem come after the leak?

Yes the problem came after the leak, so you think I still have a leak somewhere?

 

[85Hokie]

Not a leak - rather as the pump "Sucks" fluid - it is picking up air somewhere......

 

[scrappin35]

Thanks...im not sure where it could be sucking air from if there wasn't a leak. When I look down into the filler hole there's no foaming or air bubbles either which would lead me to believe there is still a leak...i could be wrong.

I still believe it has something to do with the relief valve or whatever happens when you hit the top of travel for say your 3 point. It makes the same exact sound as that when you hit around 2200 RPM.

 

[Dave_eng]

The BX25 WSM that i have shows a FEL and hoe.

Do you have the hoe on your machine now?

The hydraulic circuit is from the pump to a priority flow control which ensures the steering receives 2.1 gpm with the balance of the flow going first to the backhoe valve, then from a PB port in the hoe valve to the FEL, 3 pt, etc

The outflow from the steering controller goes to the pto clutch pack and the HST

If you do not have the hoe installed, do you have the backhoe loop properly connected? If the loop is not connected to the correct ports strange things could happen.

Dave

 

[scrappin35]

The BX25 WSM that i have shows a FEL and hoe.

Do you have the hoe on your machine now?

The hydraulic circuit is from the pump to a priority flow control which ensures the steering receives 2.1 gpm with the balance of the flow going first to the backhoe valve, then from a PB port in the hoe valve to the FEL, 3 pt, etc

The outflow from the steering controller goes to the pto clutch pack and the HST

If you do not have the hoe installed, do you have the backhoe loop properly connected? If the loop is not connected to the correct ports strange things could happen.

Dave

I have one but its not connected right now and although I hadn't checked that I just did. Its on properly and the problem still exists. I'm wondering if there is something blocking the relief valve is that possible or would it not display those symptoms?

 

[85Hokie]

I have one but its not connected right now and although I hadn't checked that I just did. Its on properly and the problem still exists. I'm wondering if there is something blocking the relief valve is that possible or would it not display those symptoms?

As Dave pointed out, if you dead headed the pump, the relief valve would be screaming all the time and the fluid would heat up very quickly.

I am sure you have heard the squeal of the relief valve in the past, do you hear it now? Or that noise not there?

 

[Dave_eng]

I have one but its not connected right now and although I hadn't checked that I just did. Its on properly and the problem still exists. I'm wondering if there is something blocking the relief valve is that possible or would it not display those symptoms?

Your symptoms do not sound like a relief valve problem to me.

I just looked on the Messicks site for details on your hydraulic pump.

It is getting its oil supply by being directly connected to the transmission and utilizing O rings to create seals.

Others have suggested the pump is sucking air. If one of the O rings was not sealing well it would allow the pump to suck air.

You may want to consider investing in a pressure gauge and some fittings to allow you to Tee into the IN line to the loader valve so you can see what is happening pressure wise when it acts up.

Dave

 

[scrappin35]

As Dave pointed out, if you dead headed the pump, the relief valve would be screaming all the time and the fluid would heat up very quickly.

I am sure you have heard the squeal of the relief valve in the past, do you hear it now? Or that noise not there?

I do so I apologize if that's wasn't clear. no squealing or screaming and hydraulics working perfectly until you either:
a). reach the top of the movement on the 3 point, where it is suppose to scream and it does... only difference is it won't release until you restart the tractor and start all over again. If you try to go down it works as designed, but as soon as you try to go up it only slips an inch or 2 down and won't go up as though its at the top.
b). same situation for the bucket as a.
c). increase RPM until about 2200 and then it starts screaming, and the hydraulics won't work.

This is why I keep thinking there is something wrong with the relief valve.

 

[scrappin35]

Your symptoms do not sound like a relief valve problem to me.

I just looked on the Messicks site for details on your hydraulic pump.

It is getting its oil supply by being directly connected to the transmission and utilizing O rings to create seals.

Others have suggested the pump is sucking air. If one of the O rings was not sealing well it would allow the pump to suck air.

View attachment 47958

You may want to consider investing in a pressure gauge and some fittings to allow you to Tee into the IN line to the loader valve so you can see what is happening pressure wise when it acts up.

Dave

I've ordered one from BXpanded, but not sure it will be here before the long weekend. I'm always open for new tools but logically I think I know what's happening. as soon as that valve opens pressure is being diverted away from the implement circuit . Thanks to both of you guys for chiming in I appreciate it.

 

[85Hokie]

I've ordered one from BXpanded, but not sure it will be here before the long weekend. I'm always open for new tools but logically I think I know what's happening. as soon as that valve opens pressure is being diverted away from the implement circuit . Thanks to both of you guys for chiming in I appreciate it.

Could the problem be in your valve body?
I realized one day that the slop in my joystick was way out of whack..... there is a nut that hold everything tight up under the stick - it is under the black plastic cover.
Not sure that it would have anything to do with this problem but .......

 

[Dave_eng]

I've ordered one from BXpanded, but not sure it will be here before the long weekend. I'm always open for new tools but logically I think I know what's happening. as soon as that valve opens pressure is being diverted away from the implement circuit . Thanks to both of you guys for chiming in I appreciate it.

Remember, the needed test is not the usual relief valve test where the gauge is at the end of a circuit.

This time you need to be Tee'd into the circuit so you can observe what is happening as the symptoms arise

Any hydraulics shop can sell you a gauge and necessary fittings.

Dave

 

[scrappin35]

Remember, the needed test is not the usual relief valve test where the gauge is at the end of a circuit.

This time you need to be Tee'd into the circuit so you can observe what is happening as the symptoms arise

Any hydraulics shop can sell you a gauge and necessary fittings.

Dave

Well I've had a hard time finding anyone that can can work me up a T fitting, but I did get the end of circuit gauge and have tested it out. When using the bucket control I get 1750 pounds of pressure when I hit the control in any direction. As soon as I let go however it slowly starts to loose pressure and will not pressure up again. It continues to loose pressure until it gets to 500 and then stays there. If I go in the opposite direction it immediately goes to 0. Meaning... say I lift the bucket 1750 when I stop it goes down to 500 until I hit the lever to go down then it goes to 0. Restarting the tractor restarts the conditions. I also placed it on the back of the tractors hydraulic port that services the backhoe. Similar situation...It hold pressure at 1750 until I hit the bucket and then the same process as previously described.

 

[85Hokie]

Well I've had a hard time finding anyone that can can work me up a T fitting, but I did get the end of circuit gauge and have tested it out. When using the bucket control I get 1750 pounds of pressure when I hit the control in any direction. As soon as I let go however it slowly starts to loose pressure and will not pressure up again. It continues to loose pressure until it gets to 500 and then stays there. If I go in the opposite direction it immediately goes to 0. Meaning... say I lift the bucket 1750 when I stop it goes down to 500 until I hit the lever to go down then it goes to 0. Restarting the tractor restarts the conditions. I also placed it on the back of the tractors hydraulic port that services the backhoe. Similar situation...It hold pressure at 1750 until I hit the bucket and then the same process as previously described.

The 1750 psi is a perfect number...... however the rest is obviously not - maybe you do have something amiss in the relief system. Pressure should hold until the fluid is cut off or machine stopped. It sounds as if it is bleeding off somewhere. Hydraulic gurus should be able to point to a possible location of anywhere the system would bleed off pressure.

 

[scrappin35]

The 1750 psi is a perfect number...... however the rest is obviously not - maybe you do have something amiss in the relief system. Pressure should hold until the fluid is cut off or machine stopped. It sounds as if it is bleeding off somewhere. Hydraulic gurus should be able to point to a possible location of anywhere the system would bleed off pressure.

Thanks... Hopefully some Hydraulics gurus will chime in soon!

 

[lugbolt]

didn't see it, but have you cleaned the suction screen?

 

[whitetiger]

My symptoms are that as long as the RPM's are below 2200 everything works fine. But if I hit the end of either the 3 point hitch travel on the way up, the top of the boom or bucket travel then everything stops working. I know that there's a release valve in play with the normal operation that kicks in when you reach these stop points, but some how that is now being triggered by my described symptoms and not releasing. The only way to get it to reset is to turn the tractor off and restart. I did a slow rev-up and again right about 2200 I can hear the pump/engine change and the hydraulics stop working.

I think that you have a faulty coupler or tip at the backhoe supply hose. When the flow and or pressure increase to a certain point, it is pushing the ball in the coupler or tip into its seat blocking the flow. When you shut off the engine, your pressure drops, and the ball is then pushed off of its seat and the circuit is open again until you increase pressure or flow and it seats again.

Your hydraulic oil flows from the pump to the steering priority valve. It supplies steering demand and the rest goes to the backhoe or loop line if the hoe is detached. The oil then goes to the loader valve, then on to the three-point valve. If the coupler fails, stopping the flow, the pump is deadheaded and no oil can get to the loader or three-point. Your steering and PTO will probably still function.

 

[scrappin35]

didn't see it, but have you cleaned the suction screen?

Yes I did as well as a full fluid change with filter... thanks

 

[scrappin35]

I think that you have a faulty coupler or tip at the backhoe supply hose. When the flow and or pressure increase to a certain point, it is pushing the ball in the coupler or tip into its seat blocking the flow. When you shut off the engine, your pressure drops, and the ball is then pushed off of its seat and the circuit is open again until you increase pressure or flow and it seats again.

Your hydraulic oil flows from the pump to the steering priority valve. It supplies steering demand and the rest goes to the backhoe or loop line if the hoe is detached. The oil then goes to the loader valve, then on to the three-point valve. If the coupler fails, stopping the flow, the pump is deadheaded and no oil can get to the loader or three-point. Your steering and PTO will probably still function.

Thanks on post #14 I was able to actually measure the pressure and report the results. So it appears that just letting go of the bucket controls initiates a power drain down to 500lbs. If I go in the opposite direction with the bucket it then goes to 0 which I believe is deadheading. Yesterday I discovered that one of my couplers was seized to the tip on the bucket. I'd never removed it in the 11 years I have owned it and it appears that at least one of the ball bearings was rusted. I replaced it with a new tip, coupler, and hose but the problem is still there. I don't have an issue with replacing that hose/coupler/tip as well and will today since I think its under the most stress being arc'd 180. I think my troubleshooting leads me to believe that I must be leaking internally somewhere. Could a cylinder being leaking if its not the relief valve? how would one isolate that? oh and I'm also hoping to have a T pressure tester made today but not sure what difference that makes. Thanks for your post!