Audi 80 B3 driver door closes only half

Hello, with my Audi the driver’s door does not close properly. If I lock with the key, then all the buttons go down as they should, only the button on the driver’s door goes up after about 1 second again a few mm. If you pull now in the locked state at the driver’s door, then the a few cm goes up to a certain point, when I pull then a little stronger then the door is open. If I lock with the key at the driver’s door and calculate vigorously after ts spin and wait 5 seconds, then it cracks, the button sinks a few mm lower than the others and the door cannot be opened, as it should be. Now I have installed a radio central lock and thus you can open the driver’s door with a little force, because the button does not go down. I don’t want to lock with keys now. Is the locking motor (Hydraulik) completely broken? Or do I just have to put a little oil there somewhere. is it going right again?