BX25D PTO Oil Pressure low!!!?

JamRockBX25

Member

Equipment
Kubota BX25DLB
Aug 27, 2020
40
1
8
Jamaica
Sounds like you got it! I just hope the clutch pack wasn't damaged too much while the pressure was low.
We have been testing the PTO and notice e.g. that after a hour or more the pressure at the valve test port gets gradually lower i.e. for each session run from cold the start pressure is 64+-psi after a hour or so of continued use the pressure drops to around 40+-psi, Note unlike before the PTO will still engage but is noticeable slower in reaching full speed and torque!... would this be a indication the "clutch pack" has been damaged ?
 

DrankTheOrangeKoolaid

Member

Equipment
M6800/M920, Case 780B
Sep 24, 2019
99
34
18
Alberta
I can't see a damaged clutch pack causing low pressure, more the other way around.

It is possible that your relief valve is partially blocked by the same stuff that was fouling your clutch valve. Or your relief valve could need replacing. It is also possible that your hydraulic fluid is contaminated.

The problem is, when you drain the system, you never get all of the old fluid out. If the old fluid was badly contaminated, you need to refill, run and drain several time. Each time you dilute the contamination until you get it down to "near zero". I have been waging a long drawn out battle with a tractor i bought last year. The hydraulic fluid was severely contaminated and I have now flushed it 12 or 13 times and the fluid is still somewhat cloudy when it drains. I am not confident that I am close enough to "near zero" for the tractor to operate properly in the cold this winter.
 

PoTreeBoy

Well-known member
Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
2,815
1,532
113
WestTn/NoMs
would this be a indication the "clutch pack" has been damaged ?
I don't think so. Probably internal leakage at the piston ring. Or I think there is a shaft seal ring that could be leaking off a little. Bear in mind that I'm no expert on these things, but you might ream that valve passage a little larger. Just a little. If you go too far, the PTO engagement will be abrupt and there could be other implications.
 

JamRockBX25

Member

Equipment
Kubota BX25DLB
Aug 27, 2020
40
1
8
Jamaica
I don't think so. Probably internal leakage at the piston ring. Or I think there is a shaft seal ring that could be leaking off a little. Bear in mind that I'm no expert on these things, but you might ream that valve passage a little larger. Just a little. If you go too far, the PTO engagement will be abrupt and there could be other implications.
now i am totally lost!
 

JamRockBX25

Member

Equipment
Kubota BX25DLB
Aug 27, 2020
40
1
8
Jamaica
I can't see a damaged clutch pack causing low pressure, more the other way around.

It is possible that your relief valve is partially blocked by the same stuff that was fouling your clutch valve. Or your relief valve could need replacing. It is also possible that your hydraulic fluid is contaminated.

The problem is, when you drain the system, you never get all of the old fluid out. If the old fluid was badly contaminated, you need to refill, run and drain several time. Each time you dilute the contamination until you get it down to "near zero". I have been waging a long drawn out battle with a tractor i bought last year. The hydraulic fluid was severely contaminated and I have now flushed it 12 or 13 times and the fluid is still somewhat cloudy when it drains. I am not confident that I am close enough to "near zero" for the tractor to operate properly in the cold this winter.
where can we locate the "relief valve" in question ??
 

DrankTheOrangeKoolaid

Member

Equipment
M6800/M920, Case 780B
Sep 24, 2019
99
34
18
Alberta
where can we locate the "relief valve" in question ??
Heck of a good question, I find the WSM less than helpful.


C42100.png

The parts catalogue is a little more helpful, but still doesn't identify if this is for the PTO clutch or not. I think parts 100, 110,80 and 90 constitute the relief valve.
 

JamRockBX25

Member

Equipment
Kubota BX25DLB
Aug 27, 2020
40
1
8
Jamaica
Heck of a good question, I find the WSM less than helpful.


View attachment 48868

The parts catalogue is a little more helpful, but still doesn't identify if this is for the PTO clutch or not. I think parts 100, 110,80 and 90 constitute the relief valve.
Thanks, DrankTheOrangeKoolaid for your,

Can anyone else confirm "PTO relief valve" location pic would be nice!?
 

JamRockBX25

Member

Equipment
Kubota BX25DLB
Aug 27, 2020
40
1
8
Jamaica
Guys thanks for all your ongoing input, note the PTO is working much better:) e.g. after the auction taken from the good advice received to date. so over the past week's of testing, we found the PTO still only works for up to a 1Hr+- from a cold start before it begins losing power and stopping, its an improvement on the 30+-min run time before, hence in our efforts to fully resolve we seeking more help!

Question1: @ PTO clutch valve R1/8 test port what is the optimal PSI reading we should be getting?

Question2: where is the "PTO clutch Relief Valve" located on the BX25DLB ? is this it Fig2-S40? if so, how would we know it's clogged! and or blocked....

Thanks
JamRockBX25
 

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JamRockBX25

Member

Equipment
Kubota BX25DLB
Aug 27, 2020
40
1
8
Jamaica
Help! please! Q. Where is the "PTO clutch Relief Valve" located on a BX25DLB ?

Thanks
JamRockBX25