As Dave said a clear tube would be better. Also you should have a little room for expansion so when things heat up you don't pressurize the system. Think upper and lower levels on the front brake reservoir. The only reason I mention that is you said when the bolt went in some fluid came out, telling me there is no room for expansion. That may cause your rear break to drag as things get warm, making more heat and worsening the problem
Just a thought.. have fun be safe!