Case Drain – KX41-2V

[xenophon.nl]

I'm looking to rent a hydraulic flail mower for my Kubota KX41-2V and I've run into a bit of a snag with the hydraulic setup. The mower I'm interested in requires a case drain, but I’m having trouble locating where this should be connected on my excavator.

Here’s the situation:

• I’ve been told that there should be a valve somewhere to convert one of the hydraulic aux line to a case drain. However, despite searching, I haven’t been able to find anything that looks like it could be a case drain connection.
• I need to figure out if there’s an existing connection I’m missing or if I’ll need to add one.

Questions:

1. Should there be a case drain connection on my Kubota KX41-2V? If so, where exactly should I be looking?
2. If I can’t find a case drain connection, how can I add one? Are there any specific parts or modifications needed to make this work?

Any advice or guidance would be greatly appreciated. Thanks in advance for your help!

I also included some pictures and diagrams.

 

[TheOldHokie]

I csnt abswer as to what is on your machine but the operators manusl should.

Functionally a case drain is simply a hose connection from the implement that goes straight to tank on the machine - aka third line. It should present as little back pressure as possible to the implement.

You can rig one yourself by adding a coupler that goes straight to tank on your excavator.

Here is a fancy OEM third line outlet manifold on a Case skid steer. The two larger lines are the normal A and B bidirectional pressure connections to the control valve. The smaller middle third line is one way into the skidsteer and does not go to the valve. It goes straight to tank.

Dan

 

[GreensvilleJay]

hmm, maybe look at the hydraulic 'drive' motors ? If they have a small 3rd hose, that'd be a 'drain' line, follow it back to the tank ??
The WSM is 'somewhere on the net' as I grabbed a copy years ago.
The challenge will be physically plumbing it. Aint a whole lotta room in the beaties for 'upgrades' !

 

[xenophon.nl]

Included is the hydraulic diagram in case of anyone is able to read that and determine if there should be a valve to activate the case drain.

 

[GreensvilleJay]

the dotted line from tank...left...up...to motors is the 'drain'. You could/would Tee into that...IF you can access it !

 

[Henro]

Included is the hydraulic diagram in case of anyone is able to read that and determine if there should be a valve to activate the case drain.

LOL… That highlighting looked familiar! I must’ve posted that image somewhere because I looked at my file for the KX-41-2V workshop manual and the highlighting is the same as I have here!

I don’t have an answer to your question. But I can say, and I think TheOldHokie would agree, that the return to tank is generally , and may be always, an unrestricted line that goes back to the tank. So if you need a return to tank route, you need to find either a line serving that purpose or you need to feed your return back to the tank somehow on your own.

 

[TheOldHokie]

LOL… That highlighting looked familiar! I must’ve posted that image somewhere because I looked at my file for the KX-41-2V workshop manual and the highlighting is the same as I have here!

I don’t have an answer to your question. But I can say, and I think TheOldHokie would agree, that the return to tank is generally , and may be always, an unrestricted line that goes back to the tank. So if you need a return to tank route, you need to find either a line serving that purpose or you need to feed your return back to the tank somehow on your own.

Yes.

Another attribute of case drains is that they should terminate below the fluid level in the reservoir.

In a pinch that could be as simple as removing the tank fill csp and sticking a hose in the tank with the end below fluid level.

Installung a tee in a valve or motor return line is frowned on.

Dan

 

[Henro]

Yes.

Another attribute of case drains is that they should terminate below the fluid level in the reservoir.

In a pinch that could be as simple as removing the tank fill csp and sticking a hose in the tank with the end below fluid level.

Installung a tee in a valve or motor return line is frowned on.

Dan

I never heard the term case drain before. Is there a reason for that term? I’ve always just heard return to tank line or something like that.

In other words, was there a point in time when some kind of hydraulic case was drained back to the tank? Just an intellectual curiosity question. An answer is likely of no use in the real world today.

 

[TheOldHokie]

I never heard the term case drain before. Is there a reason for that term? I’ve always just heard return to tank line or something like that.

In other words, was there a point in time when some kind of hydraulic case was drained back to the tank? Just an intellectual curiosity question. An answer is likely of no use in the real world today.

Its called a case drain because that is what it does. Hydraulic motors and pumps all bypass oil internally and that bypass oil gets forced into the case area outside of the pumping chamber. The result is the case gets pressurized and damages the pump/motor. Shaftvseals are psrticularly vulnerable. The cure is to plumb a dedicated drain line between the case on the pump/motor and the reservoir on the machine. That bleeds off the pressure and protects the pump/motor.

Dan