Hydraulic pressure test done - it's way low - now what?

[Teikas Dad]

OK, thank again Lou. I'll have to check some of the local shops around here and see if anyone has one of those units.

 

[JWR]

...
Before you go adding any shims I suggest you/we need to fully understand your system and where you are adding shims.

Be patient, increasing by 50 to 140 psi wont make a difference you will likely notice! ...

Dave M7040

Dave is usually right. I'm puzzled by your original post for this thread. If you get 2050 psi repeatably and the low end of spec normal is 2090 then you are less than 2% below that number. That is not what one would call 'way low' is it ? What problem or symptom did you have that caused this investigation or the motivation to change shims and change pressure ? So far I've seen nothing in the thread that seems like a problem.

( Was there some long history to all of this that is just not revisited in the thread?)

 

[Tractor Seabee]

Not familiar with the B line but my BX only has one relief valve for the implement circuit. It is integral to the HST but adjustable externally with shims. It is mounted behind the left rear wheel. Specs are 1 mm changes pressure 39 PSI. If you had the Workshop Manual all the info you need is there. Worth its weight in gold. The BX is speced to operate at 1850 PSI. I raised mine to 2000 and it increased load capability enough to tell the difference. I was tempted to go higher, but did not.

Ron

 

[Teikas Dad]

My tractor has a difficult time lifting anything more than half a bucket full of topsoil, stone or snow. I'm looking to increase the pressure at least to the top of the spec range in an attempt to improve the cabability of the loader. The tractor only has 92 hours on it so I doubt the pump is worn out. I did check the shop manual for the B3200. It explains how to replace the shims, it lists the different sizes of the shims but nowhere does it say what each shim thickness equates to for PSI increases. I wish it did...would make things much easier.

 

[Fallon]

Not familiar with the B line but my BX only has one relief valve for the implement circuit. It is integral to the HST but adjustable externally with shims. It is mounted behind the left rear wheel. Specs are 1 mm changes pressure 39 PSI. If you had the Workshop Manual all the info you need is there. Worth its weight in gold. The BX is speced to operate at 1850 PSI. I raised mine to 2000 and it increased load capability enough to tell the difference. I was tempted to go higher, but did not.

Ron

HST & impliment circuits are completely separate. HSTs are a closed center type system where impliment circuits on all CUTs & SCUTs are open center. They share a common sump & fluid, but are otherwise independent.

 

[JWR]

My tractor has a difficult time lifting anything more than half a bucket full of topsoil, stone or snow. I'm looking to increase the pressure at least to the top of the spec range in an attempt to improve the cabability of the loader. The tractor only has 92 hours on it so I doubt the pump is worn out. I did check the shop manual for the B3200. It explains how to replace the shims, it lists the different sizes of the shims but nowhere does it say what each shim thickness equates to for PSI increases. I wish it did...would make things much easier.

Yep, I understand the clarification. Of course it makes sense to get what you can out of the machine. I'm a little surprised in that my smaller Kubota BX2200 has plenty of lift to do things you have no business doing with that size tractor. I actually adapted a 50% larger bucket to mine. And my hydraulic pump has always seemed slow and anemic too. But that's a very different machine.

I'd have to say that you probably have too small a machine to to the loader work you are wanting to do with it. It's always better I think when you operate in the midrange of capacity rather than on the hairy edge.

 

[Teikas Dad]

Yep, I understand the clarification. Of course it makes sense to get what you can out of the machine. I'm a little surprised in that my smaller Kubota BX2200 has plenty of lift to do things you have no business doing with that size tractor. I actually adapted a 50% larger bucket to mine. And my hydraulic pump has always seemed slow and anemic too. But that's a very different machine.

I'd have to say that you probably have too small a machine to to the loader work you are wanting to do with it. It's always better I think when you operate in the midrange of capacity rather than on the hairy edge.

I agree completely about operating in mid range but at the very least I should be able to fill the front bucket at least to the rim with topsoil and lift it. Same thing with snow, it will lift a bucket that's almost full and snow doesn't weigh all that much. I'm not trying to lift 1500lb rocks or tree stumps, just want to be able to get a full bucket worth of material when I'm working around the yard. I don't even like driving on hills so I'm not one to go crazy trying to overload the machine. I figure if the engineers designed it to run at 2205psi then there's probably a certain safety factor built into that number. I have no intention of exceeding the specified maximum, I would just like to get a little more lift out of the loader. If an increase of 150psi will give me the ability to lift a couple hundred more pounds with the loader I'll be more than happy.

 

[Tractor Seabee]

I agree completely about operating in mid range but at the very least I should be able to fill the front bucket at least to the rim with topsoil and lift it. Same thing with snow, it will lift a bucket that's almost full and snow doesn't weigh all that much. I'm not trying to lift 1500lb rocks or tree stumps, just want to be able to get a full bucket worth of material when I'm working around the yard. I don't even like driving on hills so I'm not one to go crazy trying to overload the machine. I figure if the engineers designed it to run at 2205psi then there's probably a certain safety factor built into that number. I have no intention of exceeding the specified maximum, I would just like to get a little more lift out of the loader. If an increase of 150psi will give me the ability to lift a couple hundred more pounds with the loader I'll be more than happy.

A far as I know the B line is heftier than the BX. My BX lifts a full load plus. I lift 500# of Diesel with forks on the bucket, in and out of my PU. I believe you have a problem somewhere in your system. Looking it up in your Owners Manual what is the specified lifting capacity? I would be talking to the dealer's shop foreman. Are you still in warranty? possible the priority valve (PV) that apportions the hydraulics between the power steering and the implement circuit is not working right.

What is happening with your 3 point? W/O the BH the FEL is the first implement after the PV. This is all based on my BX diagram, the B may be different. Post the WSM flow diagram and we may spot your potential glitches. The WSM should have the pressure change per MM, mine does. The 39 psi change is probably the same.

Ron

 

[newbury]

Thanks for the input Lou. My tractor only has 80 hours on it so I'm hoping that Kubota built the pump to last a bit longer than that! I hear what you're saying about pressure to unseat the relief valve but wouldn't that show a quick spike on the gauge when the pressure is applied then drop back to the max sustained reading? I held the valve open for 15 seconds or so to let the system settle and when I had several seconds of the gauge not moving any higher I released it.

If you look back in the older posts, probably 5 or so years ago, there was a lot of discussion on people receiving Kubotas which were up to 10% under spec. It was discussed that if a dealer set the hydraulics slightly low they could rather easily turn it up. Setting it to high breaks things.

 

[JWR]

A far as I know the B line is heftier than the BX. My BX lifts a full load plus. I lift 500# of Diesel with forks on the bucket, in and out of my PU. I believe you have a problem somewhere in your system. Looking it up in your Owners Manual what is the specified lifting capacity? I would be talking to the dealer's shop foreman. Are you still in warranty? possible the priority valve (PV) that apportions the hydraulics between the power steering and the implement circuit is not working right.

What is happening with your 3 point? W/O the BH the FEL is the first implement after the PV. This is all based on my BX diagram, the B may be different. Post the WSM flow diagram and we may spot your potential glitches. The WSM should have the pressure change per MM, mine does. The 39 psi change is probably the same.

Ron

And you said "...but at the very least I should be able to fill the front bucket at least to the rim with topsoil and lift it. Same thing with snow, it will lift a bucket that's almost full and snow doesn't weigh all that much. I'm not trying to lift 1500lb rocks or tree stumps, just want to be able to get a full bucket worth of material when I'm working around the yard. "

Yeah verily. Absolutely. I think Seabee is on to something. Almost has to be something else wrong besides the measured pressure. I have used a JD4700, a BX2200, a B2150 and a MF 2660 and ALL of those would rather easily lift a full bucket of loose soil. Three of the 4 would pick up a bucket very full to overflowing with HEAVY wet clay mud (which no doubt exceeds each of the advertised capacities.) The other one I have not tried such worst case mud. I am not knowledgeable at all on the apportioning valve, etc. Seabee mentions.

But for sure, if this is new enough to be under warrantee (maybe even if it isn't) get the dealer to observe the behavior and to comment.