I hope it's okej to post a question in english (i cannot speak Russian)
There are very few ЮМЗ exkavators in Sweden and not many people to ask.

I need to change the hydraulic oil/fluid on my ЭО-2621B.

1. Should I just empty the big hydraulic oil-tank and then fill it up?
2. What kind of oil/fluid should I use?
3. How much oil/fluid should I use? 100liter?

Anything else I should think about?