My clutch pedal goes to the floor and will not come back up

Hello,

There are few reasons for the clutch pedal to go to the floor.
One of the common reasons is to have a broken clutch cable. Over time with wear and tear the clutch cable can break or come off of the bracket, which will allow the pedal to go to the floor.
Another reason could be due to low fluid level. Also having a bad master or slave cylinder can trigger the same symptom.

First you want to make sure that the fluid is at the correct level, and you do not have any leaks.

Check the clutch cable from the pedal to the transmission. One of the common failures is at the connection to the pedal on these 535i's.

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.

https://www.2carpros.com/articles/clutch-doesnt-work-sometimes-or-not-at-all