Crack below bay window

[JustInTime2021]

Should I be worried in the crack, this is below a bay window on a 1930's property.

I'm looking at changing the window, should I fix the crack before replacing or wait until the new window has been replaced and been in place for a few months.

 

[Wayners]

Not my area of knowledge but some information I picked up over the years.

Bays have no weight pushing down so if ground swells then dries with weather they are first to move.
Also a 100 years ago drainage was put in houses that run under bays sometimes, but they never compacted soil so it settled cracking wall.
Id think about drainage around the bay, and the concrete should not be tight to bricks.
May have had gravel around or even some sort of drain that was removed many years ago..
Check route of underground drains that could be causing ground erosion. Local water company will come and camera it for free in older houses I think if you can identify drain as a potential problem.

If you can't work out why it's cracked and having real concerns, its worth getting it looked at.
To fix.
Find matching brick and replace.
Use correct mortar as maybe lime based.
Coat bricks with storage dry.
You can also fit bars in the wall to strengthen

 

[^woody^]

Whats going on above? That bay corner post may be load bearing.