The brakes are by far the most sensitive parts of the T. Bad construction, cheap solutions. The price of neglect is high when out of guarantee. Once a month a nice clean with the pressure washer, and your T will love you.
On the German Forum are two How-To's. One for the front brakes and - you guessed it - one for the rears.
I asked the German thread-starter if it was allowed to translate his work and using his photo's, but till now I got no reply.
So I give you the links to the two Ho-To's. And have fun with Google Translate
How-To front brakes maintenance
How-To rear brakes maintenance