Forwarding trailer grapple/boom trouble-shooting

[fluidpowerpro]

I also noticed that it kills the engine when closing the grapple if I don't release the control quickly when the grapple is fully closed. It did not do that in the past (if the grapple was already closed and I accidentally moved the lever in the wrong direction when trying to open it, the engine would grunt a bit, but keep running, probably pushing against the pressure relief.)

This seems to suggest something is up with the engine.

[fluidpowerpro]

Of all the functions on my loader, the swing function bogs down the engine the most - whether empty or loaded; more so when the valve is fully open than throttled to a partially open position. Other functions load the engine noticeably only when running a full load, and even then not as much as swinging empty. Have always wondered why that is - never came up with an answer.

I think this is why.
Because of the length of the loader arm, quite often a lower speed is desired for the swing function. In basic systems this would be accomplished by simply installing restrictors (orifices) in the swing circuit. Because most of those systems use a fixed displacement pump, the pump is putting out a set amount of flow. In order to reduce speed by restricting the flow, the system must go the the max relief valve setting and whatever amount of oil not being used passes over the relief to tank. In this condition your drawing max HP even though your not doing max work 

[Wlmedley]

Fluidpower,I think you are right on the swing system.That's the only thing that makes sense.Manufacturer probably figured most operators will feather lever on swing function anyway as not wanting to go to fast and if it is pulled fully restrictors will limit speed.With a fixed displacement pump and probably using off the shelf parts that is about all they could do. Thanks for your explanation, I was wondering about it myself.

[Wlmedley]

Did you ever get your machine working properly.Kind of curious what the problem was.

[John Mc]

I have used it a bit. I have the impression that it will not lift as much as it used to, but no easy way of measuring that.

I have not had the time to get in to figuring out what might be going on. Health issues with my 91 year old mother, a daughter who is about to graduate from high school (winning academic awards and getting offered scholarships from all over the map, and playing on her high school softball team which has a very good chance of being state champs in their division this year), and just too much else going on in my life at the moment.

I'll get to it one of these days. I've cetainly been given enough leads to consider.