Tilt trim issue

My cap on the resovior was leaking, so I replaced it and the o ring. Now I have milky fluid and it doesn't want to go up and down unless I take off the cap and let some pressure off. Any ideas? '01 Vmax 200..

milky usually means water contamination, drain, fill, operate, repeat, till clean fluid is coming out

With the cap off, place a large oil drain pan under the motor, raise all up, fill with ATF oil, lower trim. Repeat till clean ATF oil comes out. Have had to do this many times. Found that Yamaha doesn`t like the heavy tilt and trim oil. Causes it to sound like it has air in the system, especially in cold weather.