Loader stopped raising

[Ben755]

The Koyker 155 loader on my Yanmar FX28D tractor has been raising very slowly for several months, and today it stopped raising at all. When I attempt to raise the bucket, it moves maybe 1" and makes a strained deadheading noise.
I routed the fluid return line from the loader control valve into the fluid sump and verified fluid flow. The lift cylinders on the loader show no fluid leaks and the curl and dump function appear ok. The 3-point lift also works fine. I'm suspecting
that maybe the loader control valve could have a problem. Has anyone experienced this problem and have any thoughts on a fix ?

 

[oldnslo]

Do you have quick disconnects in the loader lift lower lines? If yes disconnecting and reconnecting them. Also try swapping the lift lower lines with curl dump. Quick disconnects can fail and act like check valves.

 

[Ben755]

I replaced the quick connects with couplings some time back due to leakage issues.

 

[oldnslo]

Do both spools in the control valve move the same distance. Example: Pull the handle and both travel 1/4 inch

Should travel approximately the same distance both directions excluding float

 

[Ben755]

When the joystick is moved forward and back the top spool moves in and out about 3/8" for the lower and raise functions . The bottom spool responds to left and right movement (also about 3/8" each way) of the stick for the dump and curl functions.

 

[LD1]

If the pump is indeed making a dead heading sound, but flow verified at the outlet of the valve, that oil must be bypassing via the relief in the valve.

Either you have a blockage in one of the lines / pinched hose,

Or you have a mechanical reason for loader not raising.

When is the last time you greased the pins?
Do you have a house or Jack or some other method of raising the loader?
If so, try unhooking the lift cylinders and manually lifting the loader to see if something is binding

 

[oldnslo]

The Koyker 155 loader on my Yanmar FX28D tractor has been raising very slowly for several months, and today it stopped raising at all. When I attempt to raise the bucket, it moves maybe 1" and makes a strained deadheading noise.
Has anyone experienced this problem and have any thoughts on a fix ?

Like LD1 states: raises an inch and then stops indicates that oil is getting to the lift cylinders. Can you remove the rod end hose from the valve and place it in a bucket and then try raising the loader to see if it works now. This would isolate the loader return from the valve to potentially help isolate which component is the problem.

 

[Ben755]

Yes, I was considering removing the low pressure return when lifting line (at the cylinder) just to check for fluid bypass in the cylinder when pressure is applied. Since the bucket has been lifting slowly for some time now, maybe only one cylinder was functional and that cylinder finally failed.

 

[LD1]

If you had a cylinder.bypassing causing a slow or low powered lift, it shouldn't sound as if the tractor was going into relief and deadheading the pump