hi, sorry, i can fix a car, but I am a total computer idiot, don't even have a cellphone! by choice, not lack of financial ability!, so, I do not have a camera that will interface with the pc, and even if i did, wouldn't know how to do this. but, I'm supposed to be getting one next week, so maybe one day I'll figure this whole mess out. Again, nice Spirit! I can't believe how clean the engine bay is! Ya done GOOD! And , wow, power steering and MANUAL brakes! I did not know that AMC still did that in 81, and I have been driving AMCs exclusively since 1986. While manual brakes are a cool "old school" touch, replacing the master cylinder is a PITA. It unbolts from the INSIDE, under the dash, so, and i hope you are younger than me, it takes a few contortionist style moves to replace that thing! Uh huh, upside down , backwards, and in the dark! At my age, (56), I try not to do this anymore! But, it must be done, good brakes are your life. The one difficulty here may be actually FINDING a new manual brake master cylinder. Most auto parts places will NOT have one, it is a fairly rare part. You may have better luck contacting one of the AMC vendors, such as APD, Galvins, or Blasers. You may even end up sending yours out for a rebuild, resulting in some downtime on the car. Yours does not look that old, so you may be lucky, still, have it checked.
Anyway, if I ever figure this computer/pic thing out, I'll send a couple. good luck, gz