Mystery Leak LA402 Loader

Default Mystery Leak LA402 Loader
Hello everyone, I've got a question for all of you orange pros. I have a mystery leak coming from the FEL on the b2910. There is a few drops of oil appearing just below the loader valve. Last year we replaced the 4 lines going to the loader cylinders, we have not changed the in/out liner or the return line.

I've looked all over the loader valve area and can't seem to find the root to the leak. The return hose has a very small wet spot on it, therefore I think it has a miniature pin hole in it or something. The strange thing is, if you wipe everything clean it will stay dry for a week and then all of a sudden there is some fluid on the steel below the loader valve. I noticed it yesterday after moving a dozen buckets of top soil. Another spot I need to closely check is the loader cylinder packing, I gave it a quick look and it seemed dry.

All fittings are dry, relief valve is dry, as well as the two cylinders attached to the handle that move in and out in the spool. Sorry, I don't know the correct term for that. So it's not coming from the valve itself or any quick couplings.

Is the return line going to the rear tank always pressurized?
School me in why it has a return line, I thought it was an open center system?

If you guys need pictures I can snap some tomorrow.

Thanks Wolfman, I'm going to change all three just for good measure . The part I don't get if it is pressurized, it should leak all the time while running and working, just not a small amount on Tuesdays and Saturdays. The manual describes #80 as a return line, and it looks to go back to the tank... This is what's making me scratch my head. Does it have something to do with the float? Then again, we a rely use the float position....