JD 4610 - No Tilt Function on Loader

[kcjengr]

So today I let my neighbor use my JD 4610 tractor to pull some junk out of the woods, and for some reason half way through the job the tilt function on the JD 460 loader quit working.
I checked the usual suspects (loose QC fittings, blown hose, hydraulic level), and can not find any obvious issues.

I did notice that there is a huge amount of air in the tilt cylinders, so much so that I can manually push / pull to full extent of travel.
At first I thought maybe a piston seal failed, but if I connect the tilt hydraulic lines to the boom fittings the tilt works fine, and the boom no longer works.

Next I tried disconnecting all the QC fittings and pushing the check valve in with a screwdriver, and I am getting hardly any fluid out of the tilt QC fittings when moving the control valve to the tilt up or down positions. The odd thing is that the engine bogs as if it is building pressure.

Would what cause no fluid to these ports, but everything else on the tractor to work fine?
I am completely stumped at this point, any advice would be appreciated.

Tractor is a JD 4610 with hydro trans, factory fitted hydraulic top link and rear hydraulic ports controlled by the same lever as the loader, with factory diverter to select front or rear control.

Thank you!
Kurt

 

[K5lwq]

Is this a joystick or two separate handles? If a joystick I would suspect the pivot block under the handle boot is broken or has come loose from the curl spool.

 

[kcjengr]

It is a joystick type!
I thought of that, but the pivots appear intact and the engine bogs when the curl spool is moved one direction or the other, so the value appears to be working.
But there is no flow to the QC fittings, which does not makes any sense since its only about 24" of hard line to the QC fittings from the valve.

 

[K5lwq]

What about the rear remotes? Does the loader valve still work both remote functions when you divert flow?

 

[oldnslo]

Kc
With the engine off look at the amount off spool movement you get when moving the joystick for lift lower vs curl dump. I suspect K5 is correct in that something has worked loose on the ball joints for the curl dump have worked loose so spool is moving far enough to start blocking system flow but not allow flow out to the work ports.

 

[Hoss710]

have you looked under the bottom of the joy stick to see if and branches or sticks are stuck under there ? I had that happen once when my brother in law borrowed my tractor.

 

[kcjengr]

Thanks for all the replies!

I have rechecked the linkages, and the spools seems to be moving fully (based on the mud and rust lines on the spool).

I checked, and there is also no pressure to the rear QC ports corresponding to the tilt lines at the front.
I guess this pretty much narrows the issue down to the SCV or the diverter value.


Reading the manual, I see there is a "regen" function on the SCV when moving the joystick to the far right.
I can't say I have ever knowingly used the regen function...

From the manual

Move the lever right to divert fluid to the red connector line and return through the yellow connector line. Move the lever to the full right or “regen position” to divert fluid and apply pressure to both connector lines

What does it mean by applying pressure to both connector lines?
Could the regen valve be stuck, blocking all flow from the tilt spool?

 

[oldnslo]

Regen is another position of the main spool similar to float on lift lower so would no effect on getting pressure to QD. If diverter is just for this function i would double check to see if it is shifting.

 

[kcjengr]

The diverter looks like it diverts all functions.
I'm not extremely familiar with hydraulics, could the diverter valve get stuck in an in-between position?

 

[oldnslo]

Possible but if diverts all functions the loader would not raise.