The bearing is visible when you pull the handle, drag/bushings off, but you need to get at it from the inside. When you have done it a few times, 10-15 minutes is all it takes. Shimano is real good about sending parts when you need them. Cecelia Acuna is a great contact (949)470-4196 for parts and help. They will also provide you with a small vial of grease if you ask for it … a little dab of that on your drag washers makes for a real smooth system. A few symptoms of anti reverse bearing failure include, freespooling on a hookset, screeching on the cast, and occasionaly, you might be lifting a bait out of the water and it slips back a few inches before it catches again. You can check it by pulling on your line in front of the reel in crisp jerks, if it is bad, it will give up line and the handle will spin backwards…
Hope this helps…