790/300 loader hyd. issue when going down

[Phineas7]

<<Sorry, just realised I posted in the wrong forum!>>

I've got an odd problem. I suspect something in the valve. It loads the engine to go down with the loader. Up is fine, bucket movement is fine, 3pt hitch and T&T all work normal. With the engine off, going down barely moves. It just slowly creeps down.

I did change the hydraulic fluid a few hours ago. It seemed to happen just from one day to the next. Nothing really stands out as "happening" to the loader. I wasn't even using it. Just lifting it up off the gound for some BB work.

Any thoughts?

Regards,

P7

 

[kennyd]

Check the QD's, unplug each one and then re-connect. I'd almost bet one is not seated all the way.

 

[GREENCO]

CHECK LOCK OUT LEVER ON LOADER CONTROL LEVER

 

[Mech]

If it goes down normally when pushed into float then it isn't anything mechanical binding so, as Kennyd said, it must be something blocking flow in the hydraulics.

 

[Phineas7]

I did check the lock lever, seemed ok.

I don't think it's anything mechanically binding because it acts the same regardless of where is in the stroke and I'd expect to see some sort of twisting of odd movement if it were.

Will definitely check the QD'd when I get home. It would be easy to kick one what getting on.

Now that I think about it. I should be able to swap the lift and bucket lines as a test. If the problem moves to the bucket, it's in the valve.

 

[kennyd]

Sure you can swap hoses...but just re-seat the QD's first. There is nothing really in the valve that can go wrong.

 

[Phineas7]

I cleaned and re-seating the QD'd had no affect. I reversed the direction of the lift cylinders and noticed that there was some additional load when going up, but not as much. This would indicate the blockage is on the return circuit of the tractor side of the QD.

It's almost as if the spool on the return side it not working and that's it's working against the over pressure bypass.

I guess I need to pull off the front pannel to get a better look at the valve.

 

[prosperity]

I had the exact same problem with my 2520 w/200cx loader.

I also did the same as you did by switching the lines to isolate the problem.

It is the quick coupler - female end that is attached to the tractor.
When I called my dealer about this, he immediately said to switch out the coupler.

There is a spring and seat inside the coupler that gets cocked at a wrong angle inside - he said he has had a lot of these go bad lately.

 

[Phineas7]

ok, thanks. Had you ever disconnected your loader?
Until this issue I've never touched the QD's.

I'm going to try and talk to the dealer this week. It's a chain: They're nice guys and seem to try, but they don't appear to be the sharpest pencils in the cups. I've never talked to their mechanic though.

 

[prosperity]

ok, thanks. Had you ever disconnected your loader?
Until this issue I've never touched the QD's.

I'm going to try and talk to the dealer this week. It's a chain: They're nice guys and seem to try, but they don't appear to be the sharpest pencils in the cups. I've never talked to their mechanic though.

Yes - I've disconnected it a few times - shouldn't make a difference though. Mine didn't go bad right after a connect or disconnect. In fact, I was doing some loader work for ~3 hours when it suddenly had the same exact symptoms as yours.

My dealer said he has had a few of these go bad lately - must have been a bad batch. After I took the fitting off, and took it in, we looked closely at it, and couldn't see anything wrong visibly. But, I put the new one on and has worked perfectly since.

What happens is there is a ball, seat, and spring inside - the seat gets dislodged somehow then blocks the fluid flow.

Mine was covered under warranty - don't know if yours is or not, and don't know the cost of the fitting.