My newly acquired 1974 Eldorado convertible project car

[hornetball]

Mitch, my harness had one of these near the end of the branch that goes to the throttle linkage and distributor:

https://www.delcity.net/store/Wire-Loom-Routing-Clips/p_800840.h_800841

The nipple plugs into that bracket that you asked about earlier.

[MaR]

Mitch, my harness had one of these near the end of the branch that goes to the throttle linkage and distributor:

https://www.delcity.net/store/Wire-Loom-Routing-Clips/p_800840.h_800841

The nipple plugs into that bracket that you asked about earlier.

Thanks. I had seen those clips for sale and was wondering if that was the clip that I was missing.

[35-709]

"Since I'm not installing the heater core back into the car right now, I just blocked off the rear hose connection on the passenger side head for the time being."

Be very watchful of that rubber slip-on hose connection block-off.  They are made of thin rubber and are no where near as strong or sturdy as a piece of radiator hose, I have had one fail at the end and have heard of others doing the same.  A piece of radiator hose and a proper sized short bolt with a couple of clamps is much more trustworthy even if it is not pretty.  If you insist on using that cheap thing, always carry a spare in your glove box.

[MaR]

"Since I'm not installing the heater core back into the car right now, I just blocked off the rear hose connection on the passenger side head for the time being."

Be very watchful of that rubber slip-on hose connection block-off.  They are made of thin rubber and are no where near as strong or sturdy as a piece of radiator hose, I have had one fail at the end and have heard of others doing the same.  A piece of radiator hose and a proper sized short bolt with a couple of clamps is much more trustworthy even if it is not pretty.  If you insist on using that cheap thing, always carry a spare in your glove box.

I have seen them fail first hand. These are just temporary until I get the dashboard back into the car.

[35-709]

   Good deal.

[hornetball]

Mitch, managed to grab a picture of that bracket for you.

[MaR]

  Good deal.

The more I thought about it, the less I like having the cap on the car. I just ordered a 5/8" to 3/4" hose adapter so I can just bypass the heater core and connect the outlet directly to the radiator.

[MaR]

Mitch, managed to grab a picture of that bracket for you.

Thanks. For some reason, it seems that my harness that crossed over the AC compressor is about a foot longer than yours. I had to route it all the way toward the distributer and then back up on the other side of the carb return spring bracket to get it to fit.

[MaR]

My NOS heater core showed up. Now I can finish up refreshing the HVAC actuator box. The part number for the heater core had been superseded a few times and it seems that it was used all the way into the '90s on various vehicles. Finding an NOS unit was not that hard.

[hornetball]

Mitch, I need to get one of those Palnut drivers for my interior door panel pads.  Does yours have a size or part number marking?  Or is there only one size out there?

[MaR]

Mitch, I need to get one of those Palnut drivers for my interior door panel pads.  Does yours have a size or part number marking?  Or is there only one size out there?

The socket I have is a Snap On S9614 5/16 Palnut socket.

[6caddy2]

Excellent work!!! look forward to seeing more of your progress!! Thanks for the time you spend to post it as well!!!

[MaR]

Now that I have the new heater core, it's time to rebuild the HVAC control box. I had already disassembled it, cleaned up the parts and replaced what was broken. The first thing to go in was the foam seal behind the front diverter doors.





Next I installed the doors with their divider. The parts were sandblasted, painted and then new gaskets were made for the front and rear of the doors. The axle they ride on has to be partially pressed out and if you take it apart, make sure to put the rectangular sealing plate in with the doors and the baffle. It's very hard to fit it in after the door axle is pressed back in.





The left hand vacuum servo was broken and had to be replaced. It had a few part number changes over time and was used in many GM cars so it was not hard to find an NOS unit. The new servo fit just fine.







I then installed the door to the servo and the spring to the door. Everything was well greased as it was from the factory.






The rear servo plate was installed next. It also hold the left hand door axle in place.






The servo linkages were attached to the doors and the retainers were screwed in place with everything greased nicely.







I reinstalled the blend door into the heater core retainer frame. The upper actuator arm is retained by a black metal clip that has to be pushed up and the slid out.








The blend door arm is then fed through the HVAC box and then the heater core retainer frame is bolted to the box. When I took it apart, there was body calking between the frame and the box. I replaced it with a foam gasket as the calk had sort of oozed out in places.






Finally, I added the new heater core and reinstalled the gaskets.

[MaR]

Next up is the programmer. It was full of dust, old chunky grease and a bit of corrosion.








The control board had tons of oxidation on the on the board.






I pulled everything out except this board. I cleaned up the shell and got ready to put it all back together.





The board cleaned up nicely and bolted back in nicely.









I then started putting all the bits and pieces back in make sure to re-grease everything thoroughly. I also made an alignment mark on the gears so I could be sure to get them back exactly where they came from.
















I also marked the end of the actuator shaft so the arm could position back on correctly.







And as I tightened up the screw, the arm cracked along the bend and almost broke completely off...








A quick trip to the junkyard resulted in a suitable replacement. The actuator pin was greased and the retainer clip snapped back in.

[The Tassie Devil(le)]

Beautiful set of photos and descriptions.

I am always amazed at the levels of design and build when looking at internals, and try to think of what steps the manufacturers took when designing and constructing "stuff", and how much we actually take for granted when operating the completed articles.

I have just completed pulling a Computer Printer to pieces, and with all the complexity within, it got me to thinking about the makers, and what had to be thought of to actually get it to work in the first place.

Bruce.

[James Landi]

So true Bruce, especially when you consider how much punishment these units had to endure over the years, and, for the most part, kept on working in spite of extraordinary heat, cold, and dampness. Even now, after 50 years of existence, advertisements for Cadillac "survivors" many still have working electronic climate controls.     Jamess

[The Tassie Devil(le)]

Could it be that the Cadillac vehicles may have suffered less in the environmental wilderness simply because their owners cared for them a bit better than other brands?

Plus, with regard to the Eldorado Convertibles, their rearward rake of the windscreens, and the sturdiness of the dash tops may have also protected the dash internals from the damp elements when the roof was down?

Bruce.

[MaR]

I have to say that I had no trouble finding a replacement actuator arm in the junkyard that I use. I pulled two of them just in case I had a problem with one of them and they were both in great condition even though the cars they came out of were in horrible condition. I would even go so far as to say that the programers on both cars were probably in serviceable condition.

[hornetball]

From what I see on mine, the plastics and wiring used in this era are absolutely top notch.  For example, in my upper dash, every plastic screw post is like new and accepts/holds its respective screw without issue.  Compare that to the plastics used in newer cars where screw posts inevitably crack and have to be repaired with epoxy or plastic welding.  I'm literally afraid to touch anything plastic on my '94 Corvette for example.

[MaR]

From what I see on mine, the plastics and wiring used in this era are absolutely top notch.  For example, in my upper dash, every plastic screw post is like new and accepts/holds its respective screw without issue.  Compare that to the plastics used in newer cars where screw posts inevitably crack and have to be repaired with epoxy or plastic welding.  I'm literally afraid to touch anything plastic on my '94 Corvette for example.

Yea, with exception of some of the upper engine connector housings, every connector that I have touched has been just as flexible as new. I have not had a broken housing or stuck connector anywhere.