brake fluid reservoir leaking
 

I have a 1987 190E 2.3 16V and the brake reservoir is leaking at the bottom right side hose. the hose has rotted. My questions are;

1. what is the hose for and where does it go to.
2. can I just cut off the rotton part and reconnect the hose? while I order a new one.
3. Is it very hard to change out.

your help is very much appreciated

Rommel