Sure, it's possible to get out of the LJBF category. What matters though, is the terms that the friendship was based on. Were you the guy that always let her cry on your shoulder while she b*tched about some jerk? If you are, then you're going to have to do a lot more work. With these salvage jobs, it is always your duty to slowly transition the relationship into something else from which it already is. Patience is the key here. Become more 'busy' and not being available for all her b*tch sessions is the key. Feel free to tell her about 'other' women you've had your eye on. It will get her jealous. The goal of all of this is inducing the proper feelings in her and stimulating her mind to the point that she is receptive to your advances.
If you're her tear rag, she's coming to you as a venting session. You are her diary. She comes to you full of rage and cries, whines, and moans until she's into a cool calm. She will then proceed to leave without so much as a 'thanks'. That's her association with you. You are her emotional toilet, on which she sh*ts her problems, and then flushes (she leaves). You have to change that cycle. The problem is that she's feeling real sh*tty when she visits you and leaves the meeting all calm. Being in a calm doesn't induce one to take action. Being passionate is not having a clear mind. You have to inject some sense of horniness or other exciting feeling into her before she leaves, other than the mellowness of friendship. That boring,"lets talk your problems out and let me be your psychologist" routine WILL NOT WORK.
Whenever she looks like she's about to come over and go into her whining sessions, you have to be up front with her. "Girl, I don't want you to wallow in anger or whatever other negative feelings you may have at the moment. Right now, I want you to come over to have fun. Let's get your mind off all of those unpleasant things."
Basically, what you are trying to do is change her mindstate. Get her mind off all the bullsh*t. Once she's calm enough to have a little fun, play some games or tell her some stories that can get her mind, body, or both stimulated. I'll elaborate later, but I'm tired right now. Stay tuned.