our ten year old futura millenium is having a problem with getting an air lock in the hydralic system. about one a month the wobblers and gantry speed with slow to the point i have to disassemble the hydralic valve mechanism and bleed off a small amount of hydralic fluid. there is always some sputtering air that comes out as well. i reassemble, add a couple of qts of fluid and it runs fine for another month or so. also, my pressure gauge reads 1000 psi when machine is off and 2000 psi during operation. is this normal?