Stop being angry because seat is broken (6,4)

I believe the answer is:

settle down

I'm a little stuck... Click here to teach me more about this clue!

'stop being angry because' is the definition.
I can't tell whether this definition defines the answer.

'seat is broken' is the wordplay.
'seat' becomes 'settle' (settle is a kind of seat).
'is broken' becomes 'down' (both can mean not working).
'settle'+'down'='SETTLE DOWN'

Can you help me to learn more?

(Other definitions for settle down that I've seen before include "Become quiet and orderly" , "put down roots" .)

I've seen this clue in The Irish Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.