Changing the drive wheels, has someone done it?

Hi,

My Electrolux Pure i9 (1st gen.) has developed an error: It leaves the charging station and runs for a minute or two, then displays E15 and says "I'm stuck, please move me a little" on a smooth parquet floor. It looks like it is the drive wheel that is either malfunctioning or needs a cleaning.

Has anybody done a tear down of this model?

I would really like to know how hard I can push on the plastic bits, because I am a bit worried about taking off the front bumper, since it seems to stick to the front of the machine, even if I get the sides loose.