Farmall 560 hydraulic pressure

[Petro]

5 hours ago, snoshoe said:

Reason I asked was to open it and see if it was bad. Correct would be a flow rater between pump and valves. If you noticed no difference in pumps I have to assume it is not pump.

One more question on regulator. Does unloader piston fit in bore past flush without touching ball? Reason I ask is seat can back out and piston can not backup far enough to let ball seat.

Recently finished a thread where a piece of casting was missing from valve body. Op couldn't see problem. Neither could I from here. Symptoms were different but we could be working with something similar here. These are closed center valves. When the unloader closes. pressure is applied to all three valves. If one leaks to return. Pressure is lost to all. What I would have you do is remove one valve at a time. Use pipe spacers to put end cap on. If you get down to the hitch valve. Unhooking followup linkage will allow you to pressurize. If you still don't get your pressure back. It just leaves the housing valves are bolted to. 

The unloader piston fits way far into the bore before it touches the ball. Like a quarter inch or more. 

[VacDaddyt]

Not sure if mentioned but there will not be pressure until the pilot circuit is activated, so 500 at idle with no valve actuation is OK. It is designed to go on pressure of 12-1300 when a valve is moved only. If the screen and orifice is drilled too large to compensate for wear in the spools of the valves you may get what is happening. I have not had one get that far yet. Put gauge on and pull the lever and watch the gauge when the valve is dead headed, if it goes to 12-1300 then it is not a pump or pressure relief problem.

[Petro]

23 minutes ago, VacDaddyt said:

Not sure if mentioned but there will not be pressure until the pilot circuit is activated, so 500 at idle with no valve actuation is OK. It is designed to go on pressure of 12-1300 when a valve is moved only. If the screen and orifice is drilled too large to compensate for wear in the spools of the valves you may get what is happening. I have not had one get that far yet. Put gauge on and pull the lever and watch the gauge when the valve is dead headed, if it goes to 12-1300 then it is not a pump or pressure relief problem.

I've been checking pressure through the rear hydraulic remotes with the valve activated . . .    At idle or just above, it is making just above zero PSI with the valve dead headed.

[VacDaddyt]

I got fittings and went right on the plate the pump is mounted to also but this sounds like either the valve bodies are junk or the pressure block or both if the given you said about  pump was replaced. One plug is for the power steering the second for the main pump. I should also add maybe you restricted it too much and blew the pump which I have heard from past mechanics, been told it can be destroyed in seconds. Not sure I can add any more. Sounds weird that you can get pressure occasionally but not steady.

[VacDaddyt]

On 6/23/2022 at 1:45 AM, snoshoe said:

These are closed center valves. When the unloader closes. pressure is applied to all three valves. If one leaks to return. Pressure is lost to all.

I need clarification here. I was taught that this is considered a modified open center system. The unloader valve moving changes the flow with little pressure to flow with pressure when the pilot circuit of the valve is changed through the recesses of the valve spool being changed when you move the valve control handle. Or was I taught wrong. Here is some info from the service manuals.

[VacDaddyt]

One thing I keep coming back to is the settings for the D and S firmly set in their detents.

[Petro]

Yeah I have the same service manual. I've scoured that thing trying to find an answer but no luck. I've never seen the fluid flow picture before.  I also was told this was an open center system but maybe I was told wrong also.   "These are closed center valves. When the unloader closes. pressure is applied to all three valves. If one leaks to return. Pressure is lost to all"  Does this mean one of the valves could possibly be bad even if they all seem to function?

[snoshoe]

39 minutes ago, VacDaddyt said:

need clarification here. I was taught that this is considered a modified open center system

Can't argue. Pump is open center. If unloader closes for any reason. There is no flow through valves and system goes on pressure. Unless a spool is moved. To me that is closed center.

 

45 minutes ago, VacDaddyt said:

One thing I keep coming back to is the settings for the D and S firmly set in their detents.

This only affects the pilot ports. Can cause system to go on pressure when you don't want it to but will not cause the leak we apparently have here

[snoshoe]

4 minutes ago, Petro said:

Yeah I have the same service manual. I've scoured that thing trying to find an answer but no luck. I've never seen the fluid flow picture before.  I also was told this was an open center system but maybe I was told wrong also.   "These are closed center valves. When the unloader closes. pressure is applied to all three valves. If one leaks to return. Pressure is lost to all"  Does this mean one of the valves could possibly be bad even if they all seem to function?

Yes

[Petro]

6 minutes ago, snoshoe said:

Yes

I have a parts tractor that i know for a fact had good working hydraulics, maybe Ill pull all three valves from it and swap them in and see what happens. That maybe easier than trying to eliminate one valve at a time with spacers.

[snoshoe]

It seems unlikely to be a spool valve as it would have to leak past a work port to get to return. By eliminating pump. Anything that can cause this is unlikely. What I've listed is what I think is possible.

[Petro]

13 minutes ago, snoshoe said:

It seems unlikely to be a spool valve as it would have to leak past a work port to get to return. By eliminating pump. Anything that can cause this is unlikely. What I've listed is what I think is possible.

I'm going to spend some time on it this afternoon and go over everything again. I really appreciate your help.

[Petro]

Found the issue. Should have listened to you guys right away and checked the pump out because sure enough, this new pump is all scored inside.

[snoshoe]

I admit to being suspicious of pump from the start. This picture tells me pump is not well but does not prove it is the problem. Is the outer edge of that thrust plate where the gear teeth ride worn deeper than where smooth part of gear rides? Any slop between shafts and bushings? What does inside of housing look like? Clearance between gears and gear teeth and housing. are seals under thrust plate deformed or blown?

We're looking for a space large enough for entire output of pump to escape. The seals that pressure load the side plates would be my first suspect. I would also be looking for signs of heat, cavitation or contamination.

[Petro]

1 hour ago, snoshoe said:

I admit to being suspicious of pump from the start. This picture tells me pump is not well but does not prove it is the problem. Is the outer edge of that thrust plate where the gear teeth ride worn deeper than where smooth part of gear rides? Any slop between shafts and bushings? What does inside of housing look like? Clearance between gears and gear teeth and housing. are seals under thrust plate deformed or blown?

We're looking for a space large enough for entire output of pump to escape. The seals that pressure load the side plates would be my first suspect. I would also be looking for signs of heat, cavitation or contamination.

Both plates on the top and bottom of both gears are severely scored. There is a big chunk missing from one and the plastic seals inside are all but gone.  My picture doesn't do it justice. It's bad enough that that I'm surprised it was moving any fluid. The housing itself is good, the rest is junk. I called abilene machine and they said theyd send me another one in the mail. I told them what I found and that I opened it up to look inside, they weren't concerned a bit and told me they'd cover it without a doubt.  Fantastic customer service. 

[snoshoe]

29 minutes ago, Petro said:

Both plates on the top and bottom of both gears are severely scored. There is a big chunk missing from one and the plastic seals inside are all but gone.  My picture doesn't do it justice. It's bad enough that that I'm surprised it was moving any fluid. The housing itself is good, the rest is junk. I called abilene machine and they said theyd send me another one in the mail. I told them what I found and that I opened it up to look inside, they weren't concerned a bit and told me they'd cover it without a doubt.  Fantastic customer service. 

Sounds suspiciously like it was run under pressure. I would not install new pump without pulling orifice from regulator and making sure screen and orifice is clear. Sounds like we're getting somewhere.

[Petro]

1 hour ago, snoshoe said:

Sounds suspiciously like it was run under pressure. I would not install new pump without pulling orifice from regulator and making sure screen and orifice is clear. Sounds like we're getting somewhere.

Definitely wasn't running under pressure, been running my father's 560 for 20 years and it's very apparent when the tractor is under pressure. Just by the way the engine sounds and the pump itself. I'd never be able to pull this swather down the road in 5th gear up hills if it had been under pressure. With that said, I'm not 100% sure why it failed. I noticed when I installed it, that it did seem very difficult to turn the pump gear by hand, maybe the tolerances weren't correct.  After installing the pump, I ran the tractor for about a half hour, then installed the filter extension the next day. When I pulled the filter cover off to remove the old filter, the screen had a bunch of metal shavings on it.  I've since checked the screen 3 times in the last 6 hours of operation and it hasn't had a single bit of metal. I'm wondering if that pump did start to come apart immediately and has just been getting progressively worse. I guess time will tell. Should have it back together Monday or Tuesday. 

[jass1660]

8 hours ago, Petro said:

Definitely wasn't running under pressure, been running my father's 560 for 20 years and it's very apparent when the tractor is under pressure. Just by the way the engine sounds and the pump itself. I'd never be able to pull this swather down the road in 5th gear up hills if it had been under pressure. With that said, I'm not 100% sure why it failed. I noticed when I installed it, that it did seem very difficult to turn the pump gear by hand, maybe the tolerances weren't correct.  After installing the pump, I ran the tractor for about a half hour, then installed the filter extension the next day. When I pulled the filter cover off to remove the old filter, the screen had a bunch of metal shavings on it.  I've since checked the screen 3 times in the last 6 hours of operation and it hasn't had a single bit of metal. I'm wondering if that pump did start to come apart immediately and has just been getting progressively worse. I guess time will tell. Should have it back together Monday or Tuesday. 

Probably had enough metal wore away wasn’t a tight tolerance to make any more shavings after filter extension put on. 

[Petro]

1 hour ago, jass1660 said:

Probably had enough metal wore away wasn’t a tight tolerance to make any more shavings after filter extension put on. 

That was my thoughts. I'm assuming there was an issue with the pump right away and it self clearanced in the first 30 minutes of run time, creating the metal shavings. I'm assuming that's why I haven't seen any since.