BX25 mid-PTO loss of power

[cbrookre]

Hi all, first post here. I have a BX25 that was originally sold in 2010, but I purchased used in 2013. I bought a 54" mower deck for it and obviously still have the bucket and backhoe. Recently, the mower deck has started to lose power whenever it gets into mildly thick grass, not overly heavy and have mowed through much thicker grass in the past. The problem seems to be getting worse and gets worse the more the tractor is used. Tractor has only 450 hrs on it, had 250 when I got it.

I serviced the whole tractor including the mower deck transfer case and regularly grease all of the fittings and that does not seem to have majorly helped. The mower deck turns relatively easy by hand so I cannot believe that it is anything there. Plus when the mower deck slows or stops there is no significant change in RPM of the tractor, and all other hydraulics work fine (I can raise/lower the bucket, and the mower deck, with no problems, and the drive to the wheels is not affected). I have verified that the PTO shaft stops turning when this happens, so it is not a belt slipping on the deck. This last weekend the mid PTO stopped completely until I let the tractor rest for a while then it started working again but with the same decreased power. I do not have any accessories that attach to the back PTO so I cannot verify if it would lose power in the same way.

My guess is it is the PTO clutch or clutch relief valve, but my local dealer has said it will be ~6+ hours of labor just to figure out what is happening if it is inside of the transmission housing, and they have never seen or heard of this issue before. Searching into this forum and on the internet has not shown a similar problem. I have checked the PTO levers and they appear to be moving properly, is there anything simple that I may have missed or could be doing wrong?

Thanks in advance, this seems to be a good forum with helpful folks!

Chris

 

[cerlawson]

Sounds to me like plugged fuel filters, a common problem I have with my BX.

 

[cbrookre]

Sounds to me like plugged fuel filters, a common problem I have with my BX.

Thanks for the reply. Would that cause only the PTO to lose power? Or maybe the PTO is the first thing? About a year ago the whole tractor was losing power when climbing hills, etc, but it was basically shutting off. I replaced the fuel filters which completely fixed the issue, but this is only with the PTO, not the rest of the tractor power. I did change the rear fuel filter when I serviced it last month, but not the front one on the side of the engine.

Thanks,

Chris

 

[bxray]

Does the back pto stop as well?
Maybe the hst filter or fluid level?

 

[cerlawson]

Is there any loss of power just moving the tractor? The hydraulic pump for the HST runs all of these. The oil filter is not in that PTO line, per my book. After the pump there is the power steering controller, then the PTO clutch valve. Front and rear PTO are driven via gears after the clutch pack, so a bad clutch would affect the rear also. . With a car, sometimes the piston zone is full of crud, but I suspect that is too early for this situation.

 

[cerlawson]

There is a pressure relief valve that may be the culprit. Apparently it can be accessed from outside. If that is the case, may be an easy fix.

 

[Daren Todd]

Could it be the belt slipping on the mower deck itself?

 

[cbrookre]

Could it be the belt slipping on the mower deck itself?

Unfortunately no, the PTO shaft completely stops turning when this happens

 

[Daren Todd]

Unfortunately no, the PTO shaft completely stops turning when this happens

That sucks was hoping it was foolish and simple

 

[cbrookre]

Does the back pto stop as well?
Maybe the hst filter or fluid level?

When I tried all three positions (when the Mid PTO stopped turning altogether), the back PTO only would turn in the rear position only, it was not turning when it was selected to both.

When you say the HST filter is that the one that is white and mounted on the bottom basically next to the mid-PTO? That one was changed, and I also removed and cleaned the strainer (accessed behind the left-rear wheel). Fluid levels are not low and has clean fluid as of a month ago.

Thanks for the input!

Chris

 

[cbrookre]

Is there any loss of power just moving the tractor? The hydraulic pump for the HST runs all of these. The oil filter is not in that PTO line, per my book. After the pump there is the power steering controller, then the PTO clutch valve. Front and rear PTO are driven via gears after the clutch pack, so a bad clutch would affect the rear also. . With a car, sometimes the piston zone is full of crud, but I suspect that is too early for this situation.

No, only the PTO seems to be affected. The tractor still goes forward and reverse just fine, and the steering has no noticeable change in function, only the PTO bogs down and stops in this instance. I have to assume it is the PTO clutch not fully engaging. I was expecting if it just got overloaded it would affect the RPM's and drag the whole tractor down.

Thanks,

Chris

 

[cbrookre]

There is a pressure relief valve that may be the culprit. Apparently it can be accessed from outside. If that is the case, may be an easy fix.

That would be great, but I have no idea what I am looking for. Found the hydraulic circuit diagrams on the web, but it does not give any indication of where the parts are and what they look like, so that does not totally help (though the relief valve should be there to save the PTO from being destroyed I would guess, so it is likely). Electrical diagrams are very straightforward and easy for me, being an electical engineer, but not as experienced with anything more than basic maintenance with hydraulics. Any idea how to find and check it?

Thanks,

Chris

 

[bxray]

this may help?!
I see two in the parts list.
Maybe the one for left side?
pn 080

 

[cbrookre]

this may help?!
I see two in the parts list.
Maybe the one for left side?
pn 080

Oh great, thanks for pointing this out! Looking at the part list on Kubota website, there are two relief valves, it says "F" (080) and "R" (110). On the schematic that I saw here:

http://www.plumbers.cc/images/kubota/bx25-hyd-circuit.jpg

it shows two relief valves. It shows (8) the PTO Clutch Relief Valve and (11) a general relief valve. I am going to assume that the part (080) is for the PTO Clutch Relief Valve, anyone else know?

Either way, I will try to find the plugs and take that apart to see if anything obvious is going on in there.

Thanks,

Chris

 

[cerlawson]

Is there any chance tht the mower has found some wire and that wire is bound onto spindles and causing a drag on the torque there.

 

[cerlawson]

I copied two pages from my shop manual.

 

[cbrookre]

I copied two pages from my shop manual.

Thanks those diagrams are good, this says it is for the BX18 and 23 but I assume that it is similar to the BX25. This means that the PTO clutch pressure release valve would be on the left side if looking toward the back of the tractor. I wonder if it could have some sort of debris or blockage that prevents it from fully shutting which would sap off some of the hydraulic pressure going to the PTO. Does this sound reasonable? Either way, at my next opportunity, I will try taking it apart and see.

Best Regards,

Chris

 

[ShaunBlake]

I copied two pages from my shop manual.

cerlawson, those pages are excellent! Is that manual a Kubota publication, or another publisher? (I have pretty good Kubota manuals for B6100s but they don't compare to some of the other publications, particularly to those that NIW has access to. I'd sure like to upgrade the quality of my little library!

 

[cerlawson]

Manual came from Messicks 877-260-3528

Says for a bunch of BX tractors. Cost 85.82 including shipping.

Photos look so good it is hard to believe it is a copy. Sections have tabbed sheets.

 

[bxray]

Thinking about it and if the rear pto has no problem and the two are using the same hydraulic circuit and safety system.

The problem may not be in the safety valve.

It maybe the mmm shaft is binding.


Is there a way to put a load on the rear pto?