B7800 Relief Valve - Loader and 3pt

[JPinnell]

I've had a B7800 with the LA402 loader for almost 5yr snow with about 250hrs on it. It seems like the loader doesn't have quite the lift that it did new. I have been pushing it a bit harder than usual lately (building a limestone retaining wall) and hitting the relief valve. I know I've lost some capacity by building the pallet fork attachment and adding the Kubota branded quick attach.

If I lift something too heavy now and the relief kicks in about half the time the 3pt drops too. That means my 700lb counterweight drops and drags the ground. I don't recall it doing this when new. Luckily the loader doesn't drop, just whines like it should.

So where is the relief valve located for the loader circuit?
Is it the same one as used by the 3pt? Wheres the 3pt valve?
Is something amiss (pressure valves out of sync?) because the 3pt drops now?

I've searched about how to make a gauge to test what my pressure is (spec I believe is 2000psi) and am going to tackle that once I find out where the valves are.

 

[KennyV]

Something else is up with your 3pt...
The hydraulic pump is NOT what holds the 3pt up... it is the oil that should be trapped in the 3pt lift cylinder... KennyV

 

[JPinnell]

That makes sense to me, but I didn't know if there was a "main" overload valve that was getting tripped. 3 pt only drops when I'm working at the absolute limit of the loader, like lifting something just with the curl to drag it off the trailer. I have a 35 gal plastic barrel filled with concrete as my counterweight which should be around 700lbs, but I can occassionaly still lift a rear tire and quite often that's when the 3pt drops.