stopping power is poor.extreme force used will not stop very good!!

Sounds like a brake booster issue. You have covered all the bases. There is a professional service called Identafix. http://www.identifix.com/info/about_us.htm They only deal with professional repair shops. They are in the Minnesota 651-633-8007 begin_of_the_skype_highlighting 651-633-8007 end_of_the_skype_highlighting. You do all your diagnosis tests, and discuss your problem with a team of professional technicians great service cheap and very bright people. If your stumped this is a great service. This company only deal with automotive repair shops and don't answer questions for the general public but are an amazing knowledge base. Are you a member of iATN great network (like Linkedin for us guys that work on cars).