I recently acquired a Parker 21 that is missing its sac. The metal aerometric shell is in place, just no sac. I would like to replace it myself but can't find any info here or on YouTube about putting in a replacement sac for a Parker 21.
My experience level-I have extensive knowledge of 45s but little on older pens with sacs. I have replaced the cracked hood on another 21 I bought. I have watched Danny Fudge replace several sacs on Esterbrook Js.
1) Are there any videos or guides for replacing the sac on a Parker 21?
2) Will I need to remove the hood to remove the aerometric filler?
3) Do 21s have a breather tube? (I don't see one on mine)
Thanks for any suggestions and advice.