Kubota LA302 FEL doesn't go down

[CVF]

I've read a lot of similar threads but want to make sure I'm thinking about this right under the circumstances. Have an LA302 loader on a Kubota B7500 tractor. The lines from the quick disconnects on the joystick control to the metal lines on the FEL started leaking. Had new hoses made and replaced all four. Everything worked when the hoses came off, but now only the tilt works. The loader goes up SLOWLY (15 minutes+ from ground to top) and doesn't go down at all. I was able to open the first fitting and drain the fluid to get the FEL to drop.

Do not believe it is air in the lines. Tried replacing the quick disconnects and have plugged and unplugged dozens of times so don't believe it's a seating issue. Have also moved the disconnects around between working hoses to rule out a bad one.

So, from what I've read, I think it has to be a hose collapsed inside or debris in the return line. Could it be something else, and how would I go about diagnosing either of those problems? I'm mechanically able, but this is the first time I've ever dealt with a hydraulic system. Thanks in advance.

 

[J_J]

Bypass the QD's, and remove the hoses at the cyl and place in a bucket and activate the valve, and see if there is flow.

Put a gage on the end of the hose and take a pressure reading, or plug a gage into one of the QD's

 

[grsthegreat]

Just a quick question. When you replaced the first set of hoses, did you also replace the quick disconnects on those hoses? or reuse the old ones?. I ask this cause John Deere once replaced a line for me and installed the wrong male connector. It fit into the female connector but it wasn't long enuf to open the shut off ball in the connector. Check the number markings on the quick connects and see if their compatible. Just a thought cause it happened to me in the past.

 

[CVF]

Wish it could be as simple as a different disconnect. Only replaced one, and it's on one of the tilt lines that work.

@ JJ - I'll pick up a gauge next time I'm in town and see what I can figure out. Would I remove the hose at the head of the cylinder (furthest from the shaft) or where the shaft goes into the cylinder? Does it matter if I do one side or the other, or should I do both at once? Thanks.

 

[SSdoxie]

If it goes up really slow and will not come down means the rod and base end of cylinders are seeing the same pressure (equal pressure in both ends of the cylinder will slowly extend the rod). Double check your coupler connections. Simialr happened to me when I took loader off and put it back on. Worked for few time then quite. Took me a while but finally looked at the valve and 1 male coupler was sticky out about 1/4", didn't get locked in good.

 

[J_J]

Wish it could be as simple as a different disconnect. Only replaced one, and it's on one of the tilt lines that work.

@ JJ - I'll pick up a gauge next time I'm in town and see what I can figure out. Would I remove the hose at the head of the cylinder (furthest from the shaft) or where the shaft goes into the cylinder? Does it matter if I do one side or the other, or should I do both at once? Thanks.

You would want to test both hoses. If the hose are good, the pressure will build up to the relief valve pressure, and the relief should activate. Only do this momentary. The cyl's are connected to a tee, so plug in at the tee.

 

[Egon]

Check the hose connections making sure they are in the correct place. also look at the joystick control linkages.

 

[J_J]

Wish it could be as simple as a different disconnect. Only replaced one, and it's on one of the tilt lines that work.

@ JJ - I'll pick up a gauge next time I'm in town and see what I can figure out. Would I remove the hose at the head of the cylinder (furthest from the shaft) or where the shaft goes into the cylinder? Does it matter if I do one side or the other, or should I do both at once? Thanks.

You said new hoses made, so did the new hoses connect to the valve correctly. Check your hose connections using this as a reference. Scroll to the bottom. Fig #2

http://www.surpluscenter.com/Instruct/I9-7401.pdf

If fluid was blocked to the cyl's, the relief would activate.

If you had flow and pressure, and the fluid could not escape from the cyl, the relief would activate.

 

[CVF]

Finally got to work on it again this afternoon. One of the replacement hoses was bad - no flow through at all. Going to exchange it tomorrow and should be ready to roll. Appreciate all the help. :drink:

 

[J_J]

Who ever made up those hoses, should have blown air through the hose to clean out any debris from the cutting and make up of the hose. If it were blocked, they would have caught the blocked hose.