M819 swivel mystery electrical part?

[CUCVFAN]

Can any of you guys tell me what this marvelous little mystery part is/does? The dotted line part inside the red circle. I have not dug through every page of every manual yet, but I thought it was interesting that this is the only part on this drawing in the -34P without a number. Even the bolts and gasket have numbers!

It is mounted to the top of the swivel assembly under the boom. The single wire was not hooked to anything, but it makes me think it was some kind of pressure(?) switch that would provide a ground for a light somewhere in maybe a civilian(?) application of the boom? The M819 does not have any lights in the crane operator cab that I know of, and it would not make sense to have a light in the truck cab that nobody would see...

Apparently, it decided to spring a leak out around the wire grommet.

 

[gimpyrobb]

Should be 2 or 3 lights on the boom and operator bucket, that supplies the voltage.

 

[Csm Davis]

Gimpy is correct it should be 24v for floodlights and any other electrical around the gondola like heater. If I remember correctly it was controlled by the floodlights switch in the cab on the 816 and 819.

Sent from my SM-G930V using Tapatalk

 

[CUCVFAN]

OK, that makes sense. It was rainy and getting late and I wasn't even thinking about where the voltage for the lights would come from (not that they were hooked up, but it makes perfect sense).

So, after messing around with it, it appears to leak fluid when the boom hits the stop after getting fully retracted or extended while operating the hoist at the same time. I guess the pressure spike at the stop on each end is causing something inside to leak? Yay... It doesn't seem to leak when the boom is raised to the top nor lowered all the way. I did not rotate the boom to the stops and see if it happens at that point. I also might check if it happens just on the boom extension without the hoist operation, just for curiosity.

Any suggestions as to what may be leaking? I have never taken it apart, so I'd guess there's an o-ring or something that is failing under the pressure spike? Or, does that thing actually have some type of sealing capacity (hence the gasket)?

Thanks!

 

[Guyfang]

Can any of you guys tell me what this marvelous little mystery part is/does? The dotted line part inside the red circle. I have not dug through every page of every manual yet, but I thought it was interesting that this is the only part on this drawing in the -34P without a number. Even the bolts and gasket have numbers!

It is mounted to the top of the swivel assembly under the boom. The single wire was not hooked to anything, but it makes me think it was some kind of pressure(?) switch that would provide a ground for a light somewhere in maybe a civilian(?) application of the boom? The M819 does not have any lights in the crane operator cab that I know of, and it would not make sense to have a light in the truck cab that nobody would see...

Apparently, it decided to spring a leak out around the wire grommet.

The reason it has no part number, is because its located on another assembly, or is part of an installation kit, or is installed only on certain models of the truck. If I had to look for it, I would start with the truck wire harness, but sometimes logical thinking and Army TM's are worlds apart.