As a long time tanker, my advice to you is simple. If you want to tank, don't play a brute. They can do it, some, but not nearly as well as a true tanker. Tanks have more health, can hit the defense and/or resistance caps easier than brutes, and have more and better tools for grabbing and holding aggro. I'd post your question in the tanker forum, and I'd re-roll your rad/rad as a tank instead.