Will be changing the brake fluid on my 96 turbo wagon. I notice the inside of the plastic reservoir has a dark film on it, and from my 240 days I've removed the plastic reservoir after jerking it loose from its rubber seat so I could get to the back compartment via the bottom opening and clean it with alcohol.

I notice on the 850 there is a single torx bolt holding the reservoir to the top of the master cyliner, and, because it easily moves back and for a little bit, I suspect an o-ring at the bottom. Before I remove the torx bolt and try to pry loose the reservoir so I can clean it thoroughly and see the color of my brake fluid, is there anything I need l(like a new o-ring before I start?) to be aware of so I don't ruin or break something? Dick