don't sandblast the insdie of that pan you'll never get the sand out
buff the rust spots with steel wool and a lite oil then wipe the pan dry and hose it down with wd40 to keep it from rusting again
I have a set of guages if you just want a blow and go buy some 134a in the little cans and pm me I'll help you out....
if you want a real shop NTB downtown has an ac machine and a qualified tech
the amplifier is the module on that system if you call me thursday between 8a and 4p with the number on your amplifier I'll see if i can get you one to try and see if it fixes the problem
80psi on the low side is too high most cars should be between 15psi and 50psi
if you are sure the system is fully charged you may have a blocked orfice tube or expansion valve
all 4 wheels were toast they carved up the steering wheel with a knife and stabbed some holes in the arnrests and it stinks inside cosmetic stuff mostly
we found some paperwork in the van and figured out who stole it and more importantly where they live now I just have to make myself send the cops and not go handle it personally