L295DT Hydraulic Issue

[dhs]

Im hoping someone out there can help me

I have a 1979 L295 DT manual trans with only one hydraulic pump mounted to the rear of the fuel pump and a model 1200 loader with 2200 hrs that I only use occasionally
Was using it the other day and loader and bucket functioned properly and shut it off after 5 - 10 mins of use
Started tractor up again in the afternoon and loader and bucket would not operate I noticed that the 3 point hitch works but seems very slow , checked oil level - ok , removed supply line from loader controls and ran engine with hose into a bucket had good flow ,removed relief valve on loader control valve no debris found , removed suction screen on rh side of engine below pump and washed out screen only found some fuzz on screen , installed a tee between supply hose and loader control vavle and check pressure had no pressure on 0-5000 psi gage
Loader gets its supply from a block on lh side top of diff and returns to block as well as trans sump
I am wondering if there is another filter and relief valve somewhere in the system other than the one on the loader control valve

Thanks Don

 

[AllDodge]

You sure the loader valve is moving when the handle is moved?

 

[North Idaho Wolfman]

L295 Relief valve:

 

[dhs]

Yes the loader valve is moving when the handle is pushed forward and back
I removed the relief valve in the block on lh side under the seat spring was not broken and no debris found

 

[Dave_eng]

There would be no pressure showing in the manner in which you did your test.

Your tractor's hydraulic system is an open center one so flow is going on at low pressure all the time and it is only when there is a request for pressure caused by moving a control valve that the system pressure would rise.

This time, while your gauge is Tee'd into the system, activate a control lever and see if there is any change in pressure. A 5,000 psi gauge is OK for a properly operating system but may not be sensitive enough if there is a real pump problem. The system likely maxes out around 2,500 psi.

How many hoses are on the loader valve. 6 or 7?

Is there any other hydraulic stuff on your tractor. A stuck open control valve will just bleed off any pressure increase.

Need to consider a way to break the 3 pt and FEL apart hydraulically to try and see where your issue may be.

Once you answer the question concerning # of hoses on FEL valve,. some suggestions can be provided.

There is a free shop manual here which would be a good reference to have regardless.
https://www.manualslib.com/manual/1101745/Kubota-L185.html

Do you have power steering? There are possibly two types mentioned in WSM. If you do, identifying which one you have would be useful.
Dave

 

[dhs]

Yes the spool is moving when the leaver is pushed fwd or pulled back

 

[dhs]

There are 7 hose on the loader valve 4 to the rams 2 returns and one supply
Only one pump mounted to the rear of fuel pump
No power steering
I removed the check valve at the block at the rear of tractor no broken spring 2 shims no dirt
or debri found
I hooked up a flow control valve at the inlet of the loader valve get 2.5 gpm flow and 100 psi with load valve open 4 gpm and 1500 psi at 2000 rpm and load control valve almost closed
Im thinking that the loader controls are dumping the pressure to the sump

 

[dhs]

Thank you for your input. Im a Truck /Cummins ISX. mechanic not an Equiptment guy
Where I work we have equipment mechanics but all they know is tiger cat and linkbelt. forestry Equiptment they have an idea but have never worked on a farm tractor so they are not exactly sure but the consensus seems to be that the loader controls might be the issue

 

[Dave_eng]

There are 7 hose on the loader valve 4 to the rams 2 returns and one supply
Only one pump mounted to the rear of fuel pump
No power steering
I removed the check valve at the block at the rear of tractor no broken spring 2 shims no dirt
or debri found
I hooked up a flow control valve at the inlet of the loader valve get 2.5 gpm flow and 100 psi with load valve open 4 gpm and 1500 psi at 2000 rpm and load control valve almost closed
Im thinking that the loader controls are dumping the pressure to the sump

Lets work with the basic information you have now provided. A loader valve with 7 ports has one port called a "Power Beyond port." The identification of the port may not say PB because the valve might have been modified to add the power beyond feature through the use of an internal plug when the loader was installed. This feature is not on all loader valves which then have 6 hoses. You state two returns but this must be wrong. Try tracing both and see if one of the two does feed the rear of the tractor. If these two "return" hose were swapped recently for some reason, you might have the power beyond one in the wrong place.

The PB (Power Beyond) is present to feed pressure to the rear of the tractor likely for the 3 pt hitch and any rear remotes you might have.

Your test flows and pressures are puzzling to me. Am I correct in thinking you did the two flow tests at different engine speeds? If so this just creates confusion. You have a higher flow at high pressure than at low pressure.

Suggest you redo the test at high rpm's.

On page 55 of the WSM you downloaded, there is an exploded view of the filter arrangement for you hydraulic pump. Make very certain it is clean. I know you said you cleaned it but I just want to make certain you cleaned the one in the illustration.

Once you report back, I might be tempted to suggest you temporarily cap the hose believed to be the power beyond one to isolate the hydraulic system into just the loader. Let me think on this before you do it.

Dave

 

[North Idaho Wolfman]

Pictures of the hydraulic to tractor hook ups will help!

 

[dhs]

Yes i cleaned the filter that is on page 55 of the manual
I did do the test at 2 different rpms
I installed a new loader valve tonight and the loader works
I still think the 3 pt hitch moves slower than i remember but i will see when i connect the mower deck to the rear
The hoses had not been off the loader controls in the last 11-12 years I have had it
two hoses from the block on lh rear of tractor go to loader valve and the other hose goes into the main body of the trans case - standard trans no power steering

 

[Dave_eng]

Yes i cleaned the filter that is on page 55 of the manual
I did do the test at 2 different rpms
I installed a new loader valve tonight and the loader works
I still think the 3 pt hitch moves slower than i remember but i will see when i connect the mower deck to the rear
The hoses had not been off the loader controls in the last 11-12 years I have had it
two hoses from the block on lh rear of tractor go to loader valve and the other hose goes into the main body of the trans case - standard trans no power steering

Just double checking, did the new loader valve come with the power beyond plug or sleeve?

Dave