Brake issue

[Sven Koch <sk-svenkoch@gmx.de>]

#2224 has some problems with the brake pedal.

When I take my foot of the pedal after I stopped the car the pedal stays 
in the pushed position, the rear brake light is stillon and the brakes 
aren't totally opened.
The engine has to push against the brakes until I pull the pedal back 
with my foot!!

What could be the problem?? The booster or the master cylinder?? How can 
test the function of each without the other part??

Thanks in advance for your help

Sven #2224