The only reason to work on the air conditioning that I can
see while the dash is off is to get air distribution system working. That is all under the dash and could be
easier to work on or check out if the dash is out of the car.
I replaced the dash in my 82 which should be the same as
yours.
Here is my check list of things to do while the dash is
off: Not all of them I did and I’m sorry
I did not checkout the air distribution system while it was out and now I get
to work under the dash which is always fun.
1. 1. Replace heater core (I would put in valve to keep hot water out
of core I have those part number also)
2. 2. Replace all light bulbs (I have a good source
for the bulbs about $0.40 each instead of $2.50)
3. 3. Replace radio speakers with good quality 8 ohm
speakers (original speakers were 4 ohm
and eat up a lot of power if mismatched to new radios which are designed to
output into 8 ohm speakers)
4. 4. Replace center console if necessary (I purchase
a standard and cut out the a place for a new type radio save some money)(I will
tell you how if anyone is interested)
5. 5. Check all vacuum hose that are under dash and
replace any that show any signs of old age
Anybody else got any additions?
Be aware if your dash is old you will most likely crack it when you take it out. I do not know of anyway not to flex it to get it out. If it is bridal it will crack. I replaced min and have had it in and out for different reasons (poor planning on my part) . You will also most likely have to take off the plastic on the windshield (inside) I'm not sure you can get the dash off without doing that. Which means you will be taking all of the plastic of the inside of the windshield.
If you have to replace the dash, you will need to use the old dash as a template when installing the new one.
If you do that let me know and I have some tips for you in that area. Things I wish I had known before I did it.