2550 hydraulic problem

[DLHWoodstock]

Your tractor may not have a screen in the hyd. oil system. So understand you changed the hyd. oil filter when you changed the hyd. oil. What condition was that oil?

Sorry for the slow response but I’ve been on the road back yo GA. I changed the hyd oil and filter back about four years ago after I got her. But I only changed the hyd oil about a month ago when I changed the load control bushings and seals. The hyd oil that came out looked good and of course the new oil is so clean that it’s hard to see it on the dipstick.

 

[DLHWoodstock]

Photo below shows trans oil screen location. DO NOT TURN STROKE CONTROL VALVE SCREW without possessing a 5000 psi gauge to check stand-by pressure which should be 2250 psi! I think you're confusing "stroke control valve'' & "de-stroking valve". De-stroking valve if present will be on upper side of hyd pump.

Keep in mind over the yrs many hyd pumps have been replaced WITHOUT PERFORMING GOOD HYD DIAGNOSTICS only to determine that the replaced hyd pump in fact was good & not the hyd problem!!!!!!!!!!!!

First I need to correct one thing, we (my son and I) did check and clean the screen in the past. I had forgotten that, but he reminded me of it today.

Yes Sir you are correct I was confused and thought it was one and the same.
That is my fear! I don’t want to change anything unnecessarily and that is a real possibility when you are guessing, and I’m guessing. But I do want to thank everyone who is trying to help me. I do have a 4000 psi gauge to set the pressure when needed.

I decided to take my toys and go home. So I loaded the tractor this morning and came home today. I was informed that I needed to be in Florida tomorrow night. I should be back on Thursday night so I will not get back to it before this weekend or possibly Monday.

My plans will be to back off on the de-stroke valve while idling. Then check screen again, and change hyd filter If needed. Does that sound correct? About how far can I back out the de-stroke valve?

Thanks again

 

[DLHWoodstock]

Your tractor may not have a screen in the hyd. oil system. So understand you changed the hyd. oil filter when you changed the hyd. oil. What condition was that oil?

Yes Sir it does. That was my mistake as we (my son and I) did clean it in the past. But I will check and clean it again just to make sure.
Thank you

 

[Tx Jim]

My plans will be to back off on the de-stroke valve while idling. Then check screen again, and change hyd filter If needed. Does that sound correct? About how far can I back out the de-stroke valve?

Thanks again

Are you referring to de-stroking screw(item 43) or stroke control valve(item 27)? The 2 valves have different applications? De-stroking valve is turned clockwise(in not out) to open stroke control valve seating area to stop pump from pumping oil. Then de-stroking screw is turned CCW to allow stroke control valve to seat allowing hyd oil pumping to begin again.

 

[DLHWoodstock]

Are you referring to de-stroking screw(item 43) or stroke control valve(item 27)? The 2 valves have different applications? De-stroking valve is turned clockwise(in not out) to open stroke control valve seating area to stop pump from pumping oil. Then de-stroking screw is turned CCW to allow stroke control valve to seat allowing hyd oil pumping to begin again.

View attachment 810910

Good Morning Jim
I am glad you are willing to help, so thanks again. I have been reading through this a few times and I do think I understand (now anyway) what you are telling me about the de-stroke valve (43) so I will look for it on Tuesday. I just returned home last night from Florida and I have Japanese Pastors in for the weekend, so I will go down to the camp on Tuesday to pick this back up.

If I do have a de-stroke valve (at the top of my pump) I will turn it clockwise to release the seat while idling. Then after a few moments I will bring it back to let it reseat the Stroke control valve. Whether that works or not I will pull the screen and check it, just to see if there is anything there.

Have a great weekend!

 

[Tx Jim]

You're welcome
When you remove plug to access hyd oil screen be aware you need to block off hyd filler hole with something so as to create a vacuum or drain hyd oil reservoir. Yes one utilizes de-stroking as you stated.

 

[DLHWoodstock]

Hey Jim
I am going down in the morning to work on my tractor and I do have another question, if I may. Does 42 screw into the top of 43? I found a picture of my pump “I took in the past” and that’s what it looks like to me. I believe I do have the 40 CM pump.

Thanks

 

[DLHWoodstock]

IT WORKED!
Praise the Lord and thank you very much Jim!

This is what I did. I pressure wash away the dirt and grease so I could see what I was working on. I installed my pressure gauge and checked pressure. The pressure at idle was bouncing from 500 to 600. Then I backed out (CCW) the de-stroke (43) about 3 or 4 full turns and pressure was still about 500. I let it run for about two minutes then, I started turning in the de-stroke screw in. At some point I heard the sound of the pump changed, and the pressure started coming up. As I turned it back in the pressure came up to 800 then 1000 and by the time it was seated back into place it was at 2350. With everything back in place I backed off on the stroke control so that the pressure was set at 2250 at idle. FEL and TP worked as it did before I had this problem.

Jim I cannot thank you enough! I was afraid I was getting into something I knew little to nothing about and that I would make it worse. But with your help I had to give it a try. Thank you for the information and your patience with all my questions.

To everyone who asked questions and or gave me suggestions, THANK YOU AS WELL!

This form has saved me a lot of time and money! Thanks everyone.

David Hardin

 

[Tx Jim]

David
You're very welcome. I'm glad this Old Cogger could help you.
Jim