https://youtu.be/ABT2MRlmeSo
Contamination and leaks are usually caused by the piston slipping in the brewing unit.
You can find the video for cleaning the piston and replacing the seals under the YouTube link above.
Silicone grease and seals are available on the Migros homepage.
37 cm (the sieve is round at the front, which is the greatest depth, at the sides it is only 33 cm deep). However, the power cable is at the back. So if you push it in somewhere, you might have to add another 2 or 3 cm to avoid kinking the cable.