Kabota 7950? or a 7970 Pto issues

[Peeteeo]

Hi I am new to farming and this is my very first farm tractor . anyone know whats wrong with my pto its engages fine for about 7mins then the pto starts to slip I think. I have put another 14 litre of oil because of the oil light is stuck on but its still full and the dip still says its full. i am driving a sickler bar mower. I can stop the mower with my had . any ideas. cheers for any help

 

[Stumpy]

You've got a hydraulically actuated clutch pack in there that engages the PTO. This guy was(is) having the same problem. He measured the pressure of the hydraulic clutch circuit and found it to be low when engaged. Don't know if he's found the problem yet but I'll tell you what I told him.

It could be a faulty relief valve in the valve body that actuates the clutch, that's what I'd be checking for first. Next I'd be looking for a broken oring in the valve itself and failing that I'd be looking for signs of an internal leak in the piping to and from the clutch assembly. Maybe Vic or one of the techs has some first hand knowledge of the problem but that's what I'd be doing in your shoes.

 

[Peeteeo]

You've got a hydraulically actuated clutch pack in there that engages the PTO. This guy was(is) having the same problem. He measured the pressure of the hydraulic clutch circuit and found it to be low when engaged. Don't know if he's found the problem yet but I'll tell you what I told him.

It could be a faulty relief valve in the valve body that actuates the clutch, that's what I'd be checking for first. Next I'd be looking for a broken oring in the valve itself and failing that I'd be looking for signs of an internal leak in the piping to and from the clutch assembly. Maybe Vic or one of the techs has some first hand knowledge of the problem but that's what I'd be doing in your shoes.

Tanks mat for the reply. Me knowing nothing about machanics will pass that info on the service guy who hopefully is going to come up in the next few day coz I live so farway from a town. Hopefully I wont get a guy playing me up. cheers

 

[Peeteeo]

well that guy was not helpfull at all all he wanted was my tractor in his work shop he didnt even take it for a drive to test pto. well start again...by the way any one know where i can get a repair manual for my tractor, cheers .

 

[Peeteeo]

You've got a hydraulically actuated clutch pack in there that engages the PTO. This guy was(is) having the same problem. He measured the pressure of the hydraulic clutch circuit and found it to be low when engaged. Don't know if he's found the problem yet but I'll tell you what I told him.

It could be a faulty relief valve in the valve body that actuates the clutch, that's what I'd be checking for first. Next I'd be looking for a broken oring in the valve itself and failing that I'd be looking for signs of an internal leak in the piping to and from the clutch assembly. Maybe Vic or one of the techs has some first hand knowledge of the problem but that's what I'd be doing in your shoes.

hi stumpy to do what you said what does it involve? I am having trouble finding some one who anything about my tractor, the nearest K dealer has only been one in the last years he brought his book out and didnt know if it was a dry clutch or wet one? and more help please?..

 

[Stumpy]

Well to check the valve I'd probably remove the slide and relief valve with the valve body still on the machine and see if there are any bum orings or gunk clogging the passages. If you take the slide out be careful not to scratch or drop it, it's a precision ground piece. You can find some diagrams of what I'm talking about by going here and entering your machine's number. Then goto transmission and PTO clutch valve and PTO clutch.

If it's not something simple like that I'd probably be here asking for help myself or consulting a workshop manual in blind hope. The next step I think would be a pressure test like the other guy did to confirm it's a pressure problem to the clutch. I'm not sure where the port he used is though so you'd need a workshop manual and a high pressure gauge with the correct fitting.

 

[Bulldog]

Just for a shot in the dark, what kind of oil did you put in the system? Some oils are not compatible with a wet clutch system.

 

[Peeteeo]

hi again thxx for any help this is my first tractor and my last for that dealer. well thats what you get when you dont get into motor car instead (girls) the tracor was on the market for over a year , i thought it was because it was rough looking...
so my tractor is a wet clutch? the 2 guys who came out both didnt bring anything with them the secons brang a book but didnt know if the tractor was a dry or wet clutch.. yet he has now quoted me roughly 8000 dollars he says the tractor need to pulled appart in 2 to get to the clutch,.. the oil i put in was valvoline farmplus hydra trans i hope this means somthing... sae viscosity 10w-30 api gl -4, sae 80w, iso 68allison c3, c4 caterpiller to -2

matt that link didnt work its says not to ouside north america i am in australia... M 7950
i have done a few antadottle self tests myself the hydrolics work fine on the bucket under load no matter how much i have used it. i drove the thing around for 15 mins and used the bucket with a full load. then went into the paddock to cut some hay with the finger mower i got to about 100metre before the pto stoped well jamed because of the grass in the fingers of the blade clooged up, if i remove the clogged up grass the pto will work again but not under any load to the finger blades it stops, i can stop the the pto with my hands . the next day i started the engine drove the same path and in the exact same spot it stopped working again yet the bucket works fine under load, i moved some big logs..the first gauge on easychecker light disply which i assume is the hyrolics always comes on when the revs are above 2.5that light has always been on since i had the thing.cause i am new to the area all the farm mach around here are new to this tractor it seems . I am not sure what to do next or who to talk to. cheers for any help...

 

[Peeteeo]

Hi any more insite anyone?

 

[Stumpy]

Definitely sounds like a PTO clutch problem. The PTO clutch has a dedicated low pressure hydraulic pump driven off the back of the 3pt hydraulic pump on the right side of the engine. This picks up oil from the transmission sump (I think) and sends it to the PTO valve at I believe about 2-300 PSI which in turn pressurizes the clutch basket to engage the PTO. The front bucket may use another pump driven off the front of the crank which is why the bucket is unaffected.

I looked that oil up, it seems to be comparable with wet clutches so that's probably not the issue. About all I can offer is to get yourself a service manual and start going through the system or keep searching for someone who can troubleshoot the problem. Either the system pressure is low because the valve or pump has an issue, there is a leak somewhere in the system, or the clutches discs are worn out and need to be replaced. Oh and please don't touch the PTO with your hands!

 

[Peeteeo]

Definitely sounds like a PTO clutch problem. The PTO clutch has a dedicated low pressure hydraulic pump driven off the back of the 3pt hydraulic pump on the right side of the engine. This picks up oil from the transmission sump (I think) and sends it to the PTO valve at I believe about 2-300 PSI which in turn pressurizes the clutch basket to engage the PTO. The front bucket may use another pump driven off the front of the crank which is why the bucket is unaffected.

I looked that oil up, it seems to be comparable with wet clutches so that's probably not the issue. About all I can offer is to get yourself a service manual and start going through the system or keep searching for someone who can troubleshoot the problem. Either the system pressure is low because the valve or pump has an issue, there is a leak somewhere in the system, or the clutches discs are worn out and need to be replaced. Oh and please don't touch the PTO with your hands!

Thanks stumpy. I carnt find a leak anywhere but went for another drive today with the hay mower hay season finished 2 months ago and i still have a whole paddock which i have given up on but tried again to see if 4 time it was stop working in the same spot but this time it stopped 1/3of the distance of the other time today was much hotter day and had the revs up slightly higher too.
btw does the tractor have to be split in 2 to get to the clutch?
I will get a manuel for this tractor which all the tagges have come off them when I bought it they sold it as a 7970 but I believe its a 7950 not sure if there much difference between them the manuel has both models. but I dont think a manuel will help me a 1000 million building plan will but not a automative manuel.cheers thank for your imput..