door mirror weatherstrip question

[venom90s]

the piece of weatherstrip in between the mirror and the inside mirror corner has a piece missing and is cracked. so when ever i wash my car water leaks through and it gets the interior wet. i was thinking of using bondo to replace the missing piece and seal the cracks but i don't know if it would stick and hold to the weatherstrip. what do you guys think? do you guys suggest something else i could use?

thanks in advance

[SkinnyKibbles]

More like Bondon't, either replace the stripping or use silicone if you can.