Combines Help Cornhead dropping on F

You have a seal bad in system. With those lift cylinders being one ways, I would start with rebuilding the control valve. Now that being siad I had a leak down problem on a K2 for a while. Finially chased that one back to a pin hole in the steel line under machine, across the top of drive axle. It was a pain to find. It did not leak with header support stop in place and no way this dude was crawling under a leaking down head to check for problem.

Barring external leaks, three possibilities, 1. bad poppet 30-3056163, 2.leaking check valve 71171713 or trash in it, or the o ring around the check valve 70923376 finally 3. bad seat in the 4 way header valve that the poppet seats on. Remove the poppet and look in at the seat, it should look round and like a drill bit was just going through the metal in an inverted cone. This is the seat the poppet sets against.

Been there, done that! I owned a CII with your exact symptoms. I did the seal and poppet valve and still had the problem. Does it hold for a while when you first start the machine then start the drop_lift syndromIJ If so, then you have a cracked spool valve. As the oil heats, the crack opens and gets progressively worse. Easy enough fix but the spool valve isn't cheap. Changed the spool valve on my CII and didn't have a problem again with the corn head dropping or the flex head bobbing up and down and kicking you in the butt with every cycle to maintain float. My dealer had only had one other Gleaner crack that valve and had no reason for it, just happens sometimes. Good luck!