Custom Brush Overlap Gaps

As most adobe flash users know, there is a large problem in the brushes (default ones) that you can use, or custom brushes if you don't know what you're doing. The problem is that the brush thinks intersections are endpoints or similar, which reduces width of that section, ruining lines. I haven't actually been able to find a proper solution for this, which is... odd. So, I'm asking you guys to post instructions/guides on how to fix this problem! Note that a custom brush will be used, no complex shaping though.
Hopefully, less people will get stuck at this problem, due to this post (and it's comments)!

[If you dont understand, or need examples, here are some examples below!]