Hydraulics fail when tractor warms up?

[brain55]

The hydraulic pump is on the right hand side of the engine as you are sitting on the seat, and the hard line running back to the gear box is the suction line. Where that line goes into the gear box is also where the suction screen is located. When you change the hydraulic oil you will want to pull that screen out and clean it also. One last question to confirm that your loader is being operated off the main pump and not an auxillary pump off the front of the engine, which was common on the older B6100's. On top of the hydraulic pump on the side of the engine, there is also a steel line coming off the top of the pump running to the back of the tractor. Right in front and above the brake pedals there could be an aluminum block with two hydraulic hoses going to the loader valve, if you have this then you only have the one hydraulic pump, which I am pretty sure is what you will find. When you are changing the hydraulic/transmission oil there is more than one drain plug, there will be the one at the bottom of the mid-pto case and there will also be one on each rear axle reduction case, you want to pull all three of these plugs to drain all of the fluid. You will want to refill it with Universal Tractor Hydraulic Fluid. I'm assuming the since you used the term "petrol" you are not in the US so I won't be much help telling you where you can find the oil. I am still pretty convinced that your hydraulic pump is worn out, especially since the 3-pt is showing the same symptoms.

Brian

 

[JohninCT]

The below thread may be of help to you.

http://www.tractorbynet.com/forums/kubota-owning-operating/67415-kubota-b6100-hydraulic-issue.html

This place will email you a parts diagram that might also help you
Kubota B6100 Parts

Like others have said, getting an owners manual for the tractor would be a wise investment.

 

[autocol]

Hey guys, fantastic help, thank you!

Jim, honestly I'm under no illusions as to how much of this repair I can take on myself, but before I take it to a dealer and spend $500 plus, I'd rather change the oil and clean up filters/screens myself, to see if it's worth the effort. Especially seeing as both front tyres and toast and require replacement. I'm trying to ascertain whether I can get this tractor back in working condition for a reasonable sum, or buy a better condition unit second hand. Sentimental attachment says I would prefer the former

Brian, thanks heaps for your descriptions, I'll go and have a look now and see what I see. You correctly surmise that the US of A is not my location (though I have lived in Eugene OR for a time), because I'm an Aussie.

I think I'll change the oil and clean the screen, and see what happens. I'll come back and let you know what happens

 

[autocol]

Brian I went and had a look, as you guessed there's a block just in front of the brake pedals which has a couple of soft lines heading up to the loader valve.

I spoke to my Dad's best mate as well and he remembers thinking there was something amiss in the loader valve block. For a minute there I was excited to think I might have narrowed down the problem without doing any work :thumbsup: ... but then I realised that the rear 3PT exhibits the same symptoms so it couldn't be that, could it?

Or, would a leaking valve in the loader valve block potentially cause a pressure reduction in the whole system? I'd love it to be the valve block. Getting at the pump looks like a "remove the exhaust manifold" job, and by the looks of things that would mean "remove all the broken studs along the way"!! This old girl has spend some time out in the weather

I've ordered a workshop manual so hopefully that will start to shed some light too.

 

[brain55]

You can eliminate the possibility of it being the loader valve by bypassing it. Take one of the hydraulic hoses by the brake pedals and loop it from one fitting to the other so the loader valve won't be in the system, if the 3-point still operates the same you know the problem is not in the loader valve. If the 3-point functions properly then it is in the loader valve, likely the relief valve. If it is the hydraulic pump it is really not that tough of a job. You wouldn't need to remove the intake manifold, just the fuel filter assembly and the 2 steel hydraulic lines. Kubota uses plated bolts so they would have to be very corroded to have issues with them breaking.

Brian

 

[autocol]

Brian, you're a gun. I'll test the bypass and report back. Love your work

 

[autocol]

G'day Brian (and any other interested onlookers),

I finally got around to trying the bypass today (I'm moving house so it's all a bit chaotic at the moment).

It confirmed what you suspected Brian, which is that the hydraulic pump is probably shot. The 3PT exhibited all the same mis-behaviours as it did when plumbed through the loader valve.

A couple of questions before I go and buy and new pump:

1. What should the hydraulic oil look like? I'd describe the stuff that came out as an opaque creamy colour (with some dirty patches too).

2. How much oil should there be? I had to take off both hoses leading to the aluminium block and replace them with one I borrowed from the front of the loader in order to get a hose with the right size threads at both ends. None of the hoses appeared to be "full" of oil when I took them off, which wasn't what I expected. I would have thought that a correctly operating system would be absolutely full to the brim with oil? Like bleeding the brake line in a car, I can't imagine air in the system helping!

If it's possible that the tractor just needs a good drain and refill - how do know how much to put in, and is there some kind of trick to refilling the system and bleeding the air out? Should I be trying this before buying a new pump?

Thanks again for your help

Col.

 

[J_J]

I would definitely drain the milky fluid. It apparently has water in it. That in itself will cause poor performance. After you drain the fluid, then work all the hydraulic functions through the motions and the air should purge itself.

 

[Steve_Miller]

Was there another relief besides the loader relief valve on those tractors? I had one 15 years ago but can't remember.

Steve

 

[autocol]

I'm slowly progressing on my little tractor fellas.

Firstly, the manual I bought on eBay has arrived which has helped a bit - though unfortunately I could only find a DVD version so I have to keep coming back inside to refer to it.

However, I've now drained all the fluid (which I'm sure would have HORRIFIED you blokes), and pulled out the suction screen filter at the base of the sump which has - I suspect - highlighted the problem. The screen was nearly covered in little black chunks of what used to be a seal. I can be certain it used to be a seal, in fact, because I managed to fish a decent sized slice of it out with my finger.

So, I'd say that makes it a very good chance that if I find out where that seal is from, I'll solve my problem. So... um... how do I do that!? If a slice half an inch long managed to find it's way to the suction screen, does that give us a clue, or could it have been dragged there from anywhere in the system?

So, to put my current questions in point form:

1. Other than refilling the hydraulic oil, is there something else I can/should flush through there to get the major crap out?
2. What steps should I take to try to find my missing seal?

Thanks.
Col.