Replacing VP2 anemometer bearings

Fow a while it has become apparent that when the wind is light, the wind cups stop spinning far too readily. This is a common issue caused by the tiny bearings - which can be replaced rather than change the whole unit. I bought a set (two) from an ebay seller and they arrived several weeks ago but only just got round to installing. Once on the ground the unit can be opened using just a small hexagonal/allen key. I already had a suitable one but it is very small, no idea the exact size. I feared the studs might be seized but it opened easily enough, I think they are stainless. The cups are completely separate from the Vane, which you do not need to open but it won't hurt, and makes it easier to handle with it taken off. You need to open the central area by taking out the larger screw on the stem too. Inside a magnet spins in the central section. on the bottom a small circlip is all that stops the shaft and attached magnet sliding upwards and out. The bearings have a small flange and can be wiggled out with a small screwdriver or similar. Replacements just press in. The major risk is losing the tiny circlip, I guess a bit of wire might do to replace it. Tweezers are useful to position it for delicate replacement. Once re-installed lower speeds are being recorded much better. There was an obvious roughness in the old bearings as you spun it, however a possible temporary improvement might be made by opening it up and squirting with WD40 or similar. I was a little surprised they were somewhat rusty - but it isn't exactly sealed inside, so much as free draining. If water gets in it *should* drip out. I may be wrong but the upper section with vane does not appear to have a bearing, and might also benefit from slight lubrication. In any case it seems to be moving freely on mine, which is only about 5 years old having been replaced previously.