I had some time today so I decided to remove the evaporator so I can investigate having it modified for R134a gas. The evaporator is housed inside the RH fender, around the corner from the HVAC. Below is a pic looking to the rear of the RH fender cavity.
First step is to remove the power antenna
Next step is to undo the screws holding the unit in. Once all are removed, the unit is easy to remove, and leaves a big hole.
The evaporator unit is fully enclosed, and is quite compact.
4 bolts and nuts hold the case together. Once I removed them it split open easily. The evaporator is a genuine Harrison unit.
I will speak to some AC specialists this week and see if the evaporator can be modified to suit a R134a system.
If the evaporator can be modified (removing the heat bypass pipes), then I should be able to get the AC working. I anticipate I will need a new modern compressor, higher efficiency condensor, a new receiver/dryer and a full set of new hoses. It won’t look original, but it is about getting it to work well. I can see dollars! 😦