A little restoration is good for the soul...
Summer is over, the chain saw and wood splitter are put up for the winter and the plow is on the Mog. Time to get back to work on the old GMC.
I restored/modified the A/C unit for the truck. I decided to do it now because of my paranoia from the air cleaner housing debacle. I want to make sure that I know where the all parts will be when I finally come up with an air filter design.
Even though I purchased the truck in an area where good A/C is important (St. George, UT), I knew that there were issues. The brass gate valve in the heater hose was the first clue:
In the 5 years that I drove the truck before I started this project, the A/C performance was disappointing. I checked the pressures and they were good - so there was plenty of Freon and the compressor worked fine.
After I disassembled the A/C unit, I found that the warm/cold air damper was binding on both sides so it would not seal in either heat mode or cool mode. In fact, the gap on either side at full travel was more than an inch. No wonder, the A/C didn't work satisfactorily. The only good news is that the heater puts out so much heat that it was able to overcome the cold air coming through the evaporator (at 9000' elevation, heat is much more important than A/C). A little trimming of the damper gaskets solved the problem. Now it snuggles into the gasket on both sides and seals well.
I also decided to convert from the continuous running POA style control to the cycling compressor control. This meant a new evaporator and accumulator had to be installed. I will modify the wiring later when I complete the engine compartment harness.
Here's what it looks like all cleaned up and sitting in the truck:
Now that I have both ends fixed, I can start working on the tubing and hoses for the refrigerant.