Moving forward on 72 Ford A/C system. For some reason I've been avoiding it. I drug all the **** out of storage but it has just sat for 3 months on my workbench. Usually I keep my bench clean and void of anything that is not an 'active project'. I hoped that the clutter would motivate. Not so much as I build a bumper instead.
I guess it is because each piece has a road block of some sort, so no easy progress on any aspect. Although I had the system working, almost every component had some type of problem.
-All wiring burned out; fuse block, fan switch, A/C function switch
-Fan motor bearing shot (hence why all wring was damaged)
-Defrost duct missing
-All foam and seals shot, so heater core overwhelms A/C. disconnected hoses, no heat. heater valve shot.
And with engine swap, need to build a new compressor bracket, but the comp clutch contacts the fan. Need to decide on solution for that before building bracket, although the bracket has to be adjustable somewhat. Can't move fan forward, as there is no room between radiator. So have to modify the crank pulley or move all the drivetrain back to allow fan spacer. Can't buy a 1/4" fan spacer, so have to make one. Can get a 1/2" spacer, but can't move motor that far. There are pulley shim kits that I could stack, but that is cheesy. Tried to cut down crank pulley in lathe, but my lathe is too small.
The condenser doesn't fit in between trans cooler and grill, so grill mods and mount brackets will need to be built. The drier was mounted where the coil over tower is now, so need to find a new location and build a bracket. This will require new hoses to be made, or maybe a combo with hard lines.
I did put in provisions for wiring upgrades. I ran a dedicated 30A circuit for fan motor so current doesn't go through the main harness. Converting clutch control circuit to low current, just driving a relay to the EFI system. But EFI is active low logic so added inverter, and EFI has end control on A/C clutch.
So I started on rebuilding the HVAC box in the cab, gathering parts. Factory A/C parts are hard to find and expensive, so I repaired what I had. Fan switch also does A/C clutch control. Medium speed didn't work at all, high was intermittent. I pulled switch apart and cleaned contacts. Had to reshape the wiper to get robust operation.
The system has a switch to lock out compressor clutch when not in A/C mode that is actuated with one of the cables. It was also burned out due to the inductive nature of the clutch coil. When A/C is shut off, the magnetic field collapses and the stored energy produces damaging high voltage/current in the circuit. This switch will become isolated behind a relay, and relay protected with a 'flyback' diode.
The heater core is the last item to come out of the assembly, making it the worst thing to have to service. It wasn't leaking, but I pressure tested it and cleaned it.
I imagine you can relate.
