Mitsubishi 1.5 ton excavator hydraulic issue

[vdubstreets]

I have a gray market Mini-ex ME-15 which I believe to be a Mitsubishi 1.5 ton machine. Perkins diesel.

I recently replaced one of the hoses to the right pilot controls and now having issues with both sides pilot controls.

Machine tracks back and forth no issues. Left Side pilot controls is working intermittently, I can curl and move the arm left/right.

The right side pilot control is not moving at all, this brings the arm up towards the cab of the machine. Machine worked fine before replacing the hose, confirmed resivior was full. Tried working controls to get air to bleed out.





Is there any method to bleeding the system? There is a red error light on the machine that says "pilot".





I can find a parts manual no luck on repair manual as of yet.

 

[vdubstreets]

I've put some work into troubleshooting in the last couple weeks.
I went down the rabbit hole of a possible electrical issue given the intermittent nature and I could of sworn that when I wiggled the connectors under the arm where I replaced the hose, the functions seemed to work better. After re-soldering - new spade connectors etc I was still with the same issue, no change. This included the terminals that are the safety switch on the arm. (you can see in the picture blue wire) this is they saftey switch that wont let the machine operate when the arm rest is up.


So what I am finding now is, if I move the machine tracks, then try the arm functions MOST of the time for a short period of time. When the arm does function it moves with full power and speed. The left pilot seems to work better than the right. When I turn the bolt to swap functions I can get all the functions in the arm again at full speed and power.
I did crack open the line I replaced and I'm getting fluid out of it, fluid is clean as I ran the machine for a little while before I replaced the leaking hose constantly topping off the fluid so its got fresh fluid.

My next steps is to locate and check the pilot system filter. I'll have to dig through what documentation I have. Any other suggestions?

 

[mrmikey]

Definetly sounds like a pilot problem for sure.
Decades ago installing plow and dump body hydraulics on new tandem trucks, (worked for DOT) . We had just installed a new system that had a total of 8 valve sections and started up the truck to work everything. No matter which function you tried it would only work for a total of 2-3 seconds and then nothing until you loosened up the valve bank thru bolts and retightned them and then same thing. Ended up one of the pilot ports on the end cap was not drilled so once the passages filed there was no pilot supply from the pump to stroke it
I think you've narrowed it down by the fact that if you operate another function the screwy one will work.
N-E way, purpose of my story is, I'm wondering if the new hose is somehow collapsed internally....maybe? Dirt somehow got into the system. The system I'm used to used small, less than 3/16" diameter, ball checks to sense the highest pressure required between sections so it wouldn't take much to muck it up.
There shouldn't be a need to bleed anything as it's a flow thru system....or at least I presume it is if it's a load sensing variable displacement setup?