LarryC
Curator of #10105275
About the time that I was starting to rebuild the AC system last summer, my AC-Heater blower started to become balky. So that halted my AC project, which I will pick up in my other thread when I finish a re-build of the AC Heater box. It is just as well, since I discovered that the upper flapper on the AC_Heater box had been stuck so I was running a constant blend of external and recirculated air and didn't know it.
Also, the factory used copious quantities of some sort of tar like gunk to seal the upper housing. This had hardened over the years and eventually started to come apart and drop down into the blower. Hence the strange scrapping and flapping sounds that had begun a few years ago whenever I turned on the heater. Meanwhile the blower motor bearing had started the slow process of seizing and was gradually getting stiffer and stiffer.
That plus all the leaves, debris, and dirt collected in there over the years meant that a rebuild seemed like a good idea before proceeding with the AC restoration.
Removal of the box occurred over the last couple of days. As others have said, the process is mostly tedious but not impossible. Definitely more tedious than the master cylinders. I drained the cooling system via the two bolts on the lower coolant tubes under the frunk, and disconnected the heater hose connection at the rear to further drain the heater lines before starting in on the heater hoses at the box. The antifreeze was crystal clear, so no problems there.
Getting the box out is not too bad once you discover the angles to approach the various screws. Also there is a generous cut-out just forward of the accelerator pedal that you can get a hand through to undo the forwardmost heater hose. A deep socket 10mm is necessary for the four mounting nuts. Then the whole box gets wiggled and guided out the passenger side, stopping repeatedly to guide things past wires and edges.
I will post images throughout the process starting here with the box as is. Since no one seems to want to post pictures of the box for those who need to do this in the future(!), I will post complete views of all four sides so you can see where everything is located, including the legendary heater valve. Just having a mental picture of the arrangements is worth five shop manuals. Incidentally, the removal described in the shop manual is pretty good.
The lower housing, showing all the tar-like gunk used to seal the box and the cause of some strange sounds
The heater blower motor, 79 version
Also, the factory used copious quantities of some sort of tar like gunk to seal the upper housing. This had hardened over the years and eventually started to come apart and drop down into the blower. Hence the strange scrapping and flapping sounds that had begun a few years ago whenever I turned on the heater. Meanwhile the blower motor bearing had started the slow process of seizing and was gradually getting stiffer and stiffer.
That plus all the leaves, debris, and dirt collected in there over the years meant that a rebuild seemed like a good idea before proceeding with the AC restoration.
Removal of the box occurred over the last couple of days. As others have said, the process is mostly tedious but not impossible. Definitely more tedious than the master cylinders. I drained the cooling system via the two bolts on the lower coolant tubes under the frunk, and disconnected the heater hose connection at the rear to further drain the heater lines before starting in on the heater hoses at the box. The antifreeze was crystal clear, so no problems there.
Getting the box out is not too bad once you discover the angles to approach the various screws. Also there is a generous cut-out just forward of the accelerator pedal that you can get a hand through to undo the forwardmost heater hose. A deep socket 10mm is necessary for the four mounting nuts. Then the whole box gets wiggled and guided out the passenger side, stopping repeatedly to guide things past wires and edges.
I will post images throughout the process starting here with the box as is. Since no one seems to want to post pictures of the box for those who need to do this in the future(!), I will post complete views of all four sides so you can see where everything is located, including the legendary heater valve. Just having a mental picture of the arrangements is worth five shop manuals. Incidentally, the removal described in the shop manual is pretty good.
The lower housing, showing all the tar-like gunk used to seal the box and the cause of some strange sounds
The heater blower motor, 79 version
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