We removed the expansion valve to replace the o-rings. The original (red) o-rings are over 30 years old and have become hard and formed a taper which will reduce the sealing ability of the A/C system and eventually lead to a leak. We replaced the o-rings with new green ones from the JP3 kit. It is important to use a light layer of Vaseline to lubricate these o-rings when installing them.
We used a pick to straighten out a few of the bent fins in our evaporator core, which now looks brand-new.
We reassembled the evaporator box and used replaced the disintegrating 30-year old foam with Resilient Polyurethane Foam Strip from McMaster Carr (PN: 93275K32).
With our evaporator box assembled, we were ready to reinstall it back in the passenger footwell of the car. We can 
The installation of the evaporator box was as easy as the removal, requiring only (2) 10mm nuts to be tightened which holds it in place.
