FEL Control Question

[dhostetler]

Hello, first post here. I've posted this on another forum but thought I'd run it by hear and see if I can get more feedback. Long story short, I've had issues with my 3pt hitch lifting on a kubota L245. I've narrowed the issue down to my FEL circuit. If I bypass the FEL circuit at the block that feeds it by just taking a small section of hose and looping it from the loader hyd. supply and return - the hitch lifts fine.

So, I tore the FEL control valve apart - o rings looked good and cleaned out the relief valve. Still having the same issue. Which leads me to my question... There's three hoses connecting to the controller; excluding the hoses that connect to the FEL cylinders. Here's a picture:



If I have them mounted correctly, the left one is 'supply in' from the block, right bottom is 'supply out' back the block, right top goes to top of tranny case. The plumbing within the valve suggest that the 2 right hoses always have access to each other's fluid, with no valve control regulating the flow between the two. If fluid is freely going to the tranny through the return, how can it supply power beyond to my 3pt lift?

So... can anyone explain the reason for the tranny return line? Can I block it off? Is there some sort of check valve in-line that gives power to the hitch? Thanks in advance - I apperciate it. DH

 

[Oldtractorfixer]

Not sure of your specific tractor but you have an open circuit system. Pressure goes through the FEL valve and if not used goes on to the next item in line, maybe the 3pt. Therefore the two lines you mention are pressure in and pressure out. Often they go to a place on the other end where a line was disconnected and redirected to the FEL then back to the original line. The dump to the top of the transmission is return like when you lower the bucket and the oil (not under hyd pressure) has to return to the reservoir. So fluid should not be freely flowing back thorugh the return. If it is no pressure is going to the 3pt. It sounds like it is plumbed incorrectly. Seems like the left one should be a right one. If it is plumbed correctly and you blocked the return you wouldn't be able to lower the FEL. I hope this helps.

 

[dhostetler]

Thanks for the fast reply... your answer does help.

So in regards to testing could I disconnect the two returning lines (currently on right side), and crank the engine...if fluid comes out of one, that's my powerbeyond and need to go back to the block. If I actuate my buck drop, I should see fluid come out of the other line and that needs to go to the return on the tranny....?

 

[Oldtractorfixer]

It likely wouldn't come out either. One to trans return one to 3pt. I would connect the two that don't go back to the trans to the right. That should make the 3pt work but the FEL might not. If not reverse those two lines. Be sure you mark them so you can get back where you started if you need to.

 

[Leejohn]

If I may jump in here Oldtractorfixer, if he does like he just said oil well come out the powerbeyond port but should not come out the tank port until when one of the levers is move. If it comes out both port when turning over engine then he has no powerbeyond fitting. When checking with both ports open he might put something over the port that oil is coming out and see if it moves to the other hole. Shouldn't be any psi there to mount to anything. His picture doesn't look like it has a powerbeyond fitting, but it could just be a pipe plug inside the valve.

 

[mjncad]

First, from one Colorado member to a new Colorado member...welcome to TBN.

Second, I'm of little help in diagnosing the problem you're having; but I'm going to assume you're new to tractors and hydraulics, and I want to extend a piece of safety advice. Be careful around high pressure hydraulic fluid as the last thing you want is a hydraulic-fluid-injection-injury. From the pictures I've seen of these injuries; the term "nasty" is an understatement. Use a piece of cardboard to check for leaks at fittings. I use a piece of drywall shim cardboard. Avoid the temptation to use your fingers to check for leaks like you might do with your house plumbing. I have to keep reminding myself of that when I work on my hydraulic system.

 

[J_J]

Thanks for the fast reply... your answer does help.

So in regards to testing could I disconnect the two returning lines (currently on right side), and crank the engine...if fluid comes out of one, that's my powerbeyond and need to go back to the block. If I actuate my buck drop, I should see fluid come out of the other line and that needs to go to the return on the tranny....?

You could use air to determine the ports.

You are correct in your assumption, but hyd fluid will get messy.

PB is usually in the center of one end of the valve, and might have an extra fitting in the port.

If you put a gage in the IN port of the valve, you can use it to trouble shoot and monitor the hyd system.

 

[dhostetler]

Thanks for all the help and warm welcome. I might give air a try - that's a good idea. The valve is off the tractor and clean from tearing it apart yesterday. From what I'm hearing, PB should have fluid acces once there's fluid at the 'in' port.

I am new t tractors and hydraulics and apperciate any safety warnings. I just want to make sure I'm not missing something obvious due to my green status. LeeJohn mentioned a PB fitting. The right angle fitting on all the hoses are the same. Does the PB connection has special valving?

 

[J_J]

There are two different PB fittings.

Some valves have a hex screw that screws inside a port,. and the other PB adapter is a fitting like this.

Surplus Center - BRAND POWER BEYOND KIT

Surplus Center - P-BEYOND & CLOSED CENTER PLUG 8 GPM MB VALVES

No special valving, it is a fitting that separates the return flow and the PB flow.

Show a pic of what you think is the PB port.

 

[dhostetler]

In the first post pictur, it would be the top horizontal valve on the right. Let me know if you need a close up of the guts, or inside.

I just blew air threw the the control. All three valves have access to each other's fluid - unless some one thinks there's an easy fix, i'm thinking new controller because something is wrong (like the application) with mine.