Last fall (2021) the undercarriage project of my 1966 Cadillac Coupe deVille started. The car is in fantastic condition. The factory or dealer applied rubberised undercoating was still on the car, but on some areas it was dry and brittle. In areas where it was not applied there was some slight surface rust which I also completely removed.

VIDEO RECAP

I did not plan to do a video about the restoration, but here is a short collage of some footage I had: (on youtube you can watch it in 4k HDR

This is a short video showing what was done

BEFORE

Some "BEFORE" pictures showing how the car looked before I started working on it.

AFTER

This is how it looks now - after all the work I did. Click to see the full report.

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Tags:1966 Cadillac Coupe deVille, 1966 Cadillac Repair Tips, 1966, Restoration, Underbody, Undercarriage, Undercoating Removal, Undercoating

Until a few days ago the ATC (Automatic Temperature Control) in my low mileage 66 worked perfectly. All functions were operating as they should.
I rebuilt the carburetor and let the car idle for a while. During this I wanted all accessories to move and also turned on the heat. It came on as always and after about 30sec the blower went off again. The power servo started to move in and out all the time by itself, but the blower would stay off. The idle speed up came on and off as well depending on the placement of the power servo. After a while it stopped doing this and stayed in the fully retracted position (full heat). If I turned the temperature dial it did not change anything - but it was around freezing outside and this is what it should, do as the sensors sense the low temperatures and then send the system into full heating mode.

I checked the following things.

• Master Switch seemed to work and gets engaged by vacuum. Power is going through it as it should. Current is going in and out. (This is what I thought…)
• Blower Motor tested with a direct feed - worked
• Blower Motor Relay - tested. Put a 12 V feed to the dark blue connector and it engaged and the blower motor came on. There was no current coming through the blue wire though.
• Power Servo - cleaned all contacts and measured the resistance in all positions  - looked good to me
• Control Head in Dash - removed it and checked the blower switches - it seemed to work.

I checked the amplifier part and the big square resistor  was showing the 50 Ohms it should. Also measured the rheostat on the temperature dial, which seemed to work as well.

Full vacuum was applied to the power servo, and I also checked the vacuum and voltage at the transducer. I also checked all vacuum actuators with a vacuum gauge, but everything checked out perfectly.

I then put everything back together. Still the system did not work in the full heat position. I did a lot more tests and checked the vacuum and electrical diagrams.
I ordered the 1966 AC manual from "Cadillac Tim" which is available also on ebay for $45,- . These instructions are a must-have for your car, as everything about the AC system is explained very well by Tim. There is a great troubleshooting guide in there. Its money well spent! Tim also offers a rebuild service for many Cadillac parts and has a great selection of refurbished parts. Check out his website!

The 1966 dash control unit - here you can see the amplifier part.

After days of troubleshooting it finally dawned on me where the problem was. I had checked the master vacuum switch multiple times and when checked it always had electrical continuity. But I did not check it correctly. I only pushed the backside of the switch until I heard a click.
I should have tested it with full vacuum applied. As it turned out, if high vacuum was applied to the switch (during heating mode), the switch did no longer work correctly!

The contacts did no longer touch when full vacuum was applied to the switch…

Today I took it apart and made a video about it. As it turned out the switch contacts did not align as they should and I had to bend it a little bit to make it work again. I then put everything back together and now the AC system works perfectly again. Check out the video for all the details!

Tags:AC, Master Switch, Master Vacuum Switch, Vacuum Master Switch, 1966 Cadillac Coupe deVille, 1966 Cadillac Repair Tips, 1967 Cadillac Eldorado Repair Tip, 1967 Cadillac Repair Tip

I am planning to clean up the undercarriage of my 66 Coupe deVille during the long winter months. The car is in fantastic condition. There is still the original undercoating on the car. In areas where it was not applied there is some slight surface rust which I would like to remove and conserve everything.

To make the car perfect again I will also dry ice blast the undercarriage and totally clean it up like I did on my 74 and the Roadmaster to preserve it as good as possible.
Today I started to brush some of the surface rust away. After that I will apply some rust remover.
I took some "before" pictures and a video.

It will be a long and dirty job…

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Tags:1966 Cadillac Coupe deVille, 1966, 1966 Cadillac Repair Tips, Underbody, Undercarriage, Undercoating Removal, Undercoating

A few years ago I sold my awesome, low mileage, all original 1966 to a friend. I always regretted that I sold it, but I did not have any other option back then.

Through a couple of car trades within my Cadillac friend community, the car became available again, and my dear friend Georg helped me to get it back.
I can't thank Georg enough - without him I would have never gotten the car back!
Today was the day to pick it up at my Georgs garage and drive it home, although I do not really have enough garage space anymore…
READ MORE!

Taking over the keys - THANKS MY FRIEND!!!!

This is how the shop messed up the ATC system of the car… I reversed everything back to original!

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Tags:1966, AC, 1966 Cadillac Repair Tips, 1966 Cadillac Coupe deVille, Master Switch, ATC, ACC, Master Vacuum Switch, Blower

A couple of years ago I unfortunately had to sell my low mileage all original, highly optioned, bucket seat 1966 Cadillac Coupe de Ville. The car went to a good home to Berlin to a friend of mine. A few car trades later and through a great great friend of mine the car somehow found its way back to me! I sold it when it had 22.500 miles on the clock and a few days ago on my birthday I got the Bill of Sale for it. I will pick it up soon and bring it back to its old/new home! You can see the details of my car here.

Tags:1966, 1966 Cadillac Coupe deVille

Today was a very sad day for me, but a very happy day for another Cadillac collector.
As I can´t keep all Cadillacs which are in my garage I had to let one Cadillac go to another care taker to free up some money. The new owner got a fantastic car and he drove it all the way to Berlin without a single problem on the hottest day of the year with a lot of traffic jams and a 13 hour drive.
This 1966 is a very special, very original and extremely well optioned car and there is no chance to find another one as good and original as this one. I know that I will regret selling it forever, but I´m glad that it found such a good home. There is a good chance that I will be able to see the car again at some Cadillac Meetings in Europe.

I really hope that I won´t be in the situation again to have to sell another car - I just love them way too much to let any of them go.

The last picture I took of the 66 together with the 74 before the new owner took over. This is an awesome 22k miles car which you have to experience, as words cant describe how special it is. Many happy miles to the new owner!

Tags:1966 Cadillac Coupe deVille

I like it when everything works on all cars.
So it was time to service some of the clocks which stopped working over the years.
The clock in the 66 did not work at all.
It's extremely simple to remove on the 66 as you can get it out of the instrument panel by just unscrewing one bolt.
The clock was very dirty in the clock work and needed a good cleaning and some good lubrication. Also the contact of the coil was a little worn and this was fixed. It then happily ticked back to life and now works perfectly.

The clock on my 58 stopped working a couple of years ago. So it came out as well. It's a little more complicated to get it out though...
When it was finally out - it could be seen that the coil was burnt and that it needed some very good cleaning as well. Some of the melted insulation material was all over the clock mechanism and of course I had no spare coil for it - so the original one had to be rewound with some good wire from a left over light solenoid...
Wow - this really took a while - but now the clock works perfectly again!

I was not so lucky with the clock on the 67 Eldorado which only worked when the car was warm. To take it out you have to remove the upper dash and then get out some light bulbs and disconnect it from the printed circuit.
It was also cleaned and lubricated and the clock worked, but it made a very loud noise when the coil rewound the spring of the clock.
The sound got better over night, but then the clock stopped working completely... It's a Westcox clock which uses a double coil and is much more complicated to rebuild than the Borg clocks. Its also almost impossible to find parts for it, as Borg clocks are much more widely used.
Looks like I will need a new 1967 clock and replace it with a Borg unit :-(

The clock in the 66 is now working perfectly again.



The disassembled clock of the 58 Eldorado.

The coil was burnt on the 58 clock.

Fully cleaned clock.

Back together with a rewound coil.

Back in the car - working perfectly again.

Tags:1966 Cadillac Coupe deVille, Restoration, Clock, 1967, 1967 Eldorado, Eldorado, Deville, 1958 Cadillac Repair Tip, 1967 Cadillac Eldorado Repair Tip, 1967 Cadillac Repair Tip, 1966 Cadillac Repair Tips, 1958

The 1966 Coupe deVille is a very well equipped car with lots of options.
Too bad that almost nothing worked when I got the car.
Of course I do not accept any non working things on my cars.
So with the help of another Cadillac aficionado who likes to work with anything electric - we took on the big challenge to repair the “Perfect Circle Cruise Control“ of the 66.
We had no idea how it worked and only had the shop manual as a reference.
The speed reminder function did kind of work, but the cruise control function was completely inoperative.

It took us a couple of days to fix it properly and now it works like the day the car left the factory!

We encountered a multitude of problems:

• 1) The dash mounted switch was defective - the plastic gear to set the desired speed was broken.
• 2) Most of the contacts inside the unit were oxidized
• 3) We had to adjust the contacts inside the unit properly and calibrate the system to the speed set on the dial
• 4) As it turned out later the brake switch was not properly adjusted (we should have checked this first and read the shop manual properly...)

After a lot of trial and error we eventually learned how the system works and we finally could adjust it correctly. It's a very nice system when it works properly, but you really have to calibrate it correctly. It's a fascinating option and there is some great engineering behind it. As it is rather complicated to repair you will see a lot of 60s car without a working cruise control.
Luckily its pretty well described how to adjust the contact points in the shop manual and I should have read it more thoroughly before we started to work on it - it would have saved a lot of time troubleshooting.

UPDATE: Here is the chapter about the Cruise Control from the 1967 Cadillac Shop Manual as a downloadable pdf file. I do no longer have the 1966 manual - thats why I have this document for 67 only. Its very similar to 1966 and differs mainly from the set switch.

inside the system - still on the car

the “perfect circle“ unit on the bench

on the bench

the dash mounted control switch disassembled

the broken plastic gear before we repaired it

the rebuilt and perfectly cleaned unit - back in the car

Tags:Cruise Control, 1966 Cadillac Repair Tips, Restoration, Perfect Circle, 1966 Cadillac Coupe deVille

When the 1966 Coupe deVille arrived at my garage the AC was completely inoperable. Nothing worked - the blower would not come on at all.
So I started to search for the cause of the problem.
Everything seemed to be fine on the vacuum side. When the lever on the control panel was moved all the vacuum actuated doors operated and the master vacuum switch also seemed to work.
After some searching I found out that no current was flowing through the master vacuum switch on the firewall.
So the switch was taken apart.
If you do this you have to be very careful not to damage the membrane.
The contacts inside the switch were oxidized and so no more current could flow through.
The contacts were also adjusted so that the switch could engage properly when vacuum was applied.
When everything was put back together the whole system once again worked as it should.
It works absolutely perfect now.

*UPDATE 2022* - Check out this article and video as well!
Unfortunately I forgot to take pictures of the switch rebuild but here is a video on youtube where a gentleman explains how this switch works…

A video that explains how this switch works


The original AC system of the 1966 Coupe deVille is now working perfectly again.

Thats the master vacuum switch which was defective.

The rebuilt master vacuum switch.

Tags:AC, 1966 Cadillac Repair Tips, Restoration, Video, Power Servo, Rebuild, Vacuum diagram, 1966 Cadillac Coupe deVille, Master Switch

The 1966 is a fantastic car - but as most low mileage cars, it sometimes needs some work to fix some minor problems which were caused by not using the car for a longer period of time.
One of the few problems this cars had were some weird issues with the turn signal lights.

I´m a perfectionist and everything has to work on the Cadillacs that are in my garage ;-) - thats one of my rules ;-)

Strange things happened on the right rear and front turn signal lights when the headlights were on or off...

This light switch is made of "unobtainium", so I was pretty scared that it could be broken.

The switch is located underneath the dash and is screwed onto the steering column and is controlled and actuated by a steel cable that is coming from the turn signal lever.

On this car the cable was out of alignment and did not engage the switch correctly on the right side position and this intermediate position of the switch caused the various problems.
It took me quite a while to get the adjustment of the cable right again, as you carefully have to shorten or lengthen it with a nose-plier to get the right length.
I also adjusted the spring you can see on the picture below. This makes the switch more snappy. It now works perfectly and the lever moves much nicer!

the 1966 Cadillac turn signal switch as seen from underneath the dash - already removed from the steering column.

Tags:1966, 1966 Cadillac Repair Tips, 1966 Cadillac Coupe deVille, Turn Signal Switch, Restoration

Today was the day the 1966 Cadillac Coupe deVille finally arrived! It's a completely original super low mileage car in pristine condition. With only 22k miles on the clock and all the mechanical parts in exceptionally good condition, the car absolutely drives like a new car.
Wow - talk about a time-capsule! You will very rarely see a car from the 60s in such original low mileage condition.
It normally takes me a couple of weeks to clean and detail a car to my standards - but this car was taken care of so well - that I´ll be able to clean this handsome car within 2 days...

What makes this car so special is of course its originality and awesome condition with the low mileage, but it also is a very loaded car with most of the options that were available back in 1966. One of the coolest option are the power - bucket seats in full black leather with center console.
Also AC, Twilight Sentinel, Automatic dimming, AM-FM radio, Cruise Control, Tilt and Telescope steering - everything is there!

What also makes this car so rare is that it is a slick top - most Coupes were ordered with vinyl tops in 1966. In my personal opinion it looks so much better and more elegant without the vinyl roof!
There is very little patina on the whole cars and one can hardly believe that this car is 48 years old...

The 66 on the trailer

At home in front of the garage

It needed a good shower first

the 74 and the 66

Inside the garage - where it will be brought to my standards now

the 66 and the 58 Eldorado

Tags:1966 Cadillac Coupe deVille, Bucket seats, 1966

I found a fantastic, low mileage all original 1966 Cadillac Coupe deVille in Los Angeles through Facebook. This 21k miles, very well optioned car will be on its way to Austria hopefully very soon.
The car is all original - including original paint and is in very good mechanical condition as well. It has most of the available options that were offered in 1966.
Its very rare to find a Coupe deVille without a vinyl top. It also has the ultra rare and very expensive bucket leather seats with center console. The car comes from a Cadillac Collector and was pampered its entire life. The mileage is fully documented and accurate. I´m a big fan of the “Antique gold metallic" paint and the black leather interior is absolutely stunning.
Can´t wait to see the car in real life in about 10 - 12 weeks after it has crossed the Atlantic.
More details and pictures will follow once the car is in my garage.

This picture was taken in Joshua Tree National Park by the previous owner



Very nice and clean engine bay

Ultra rare leather bucket seats with center console

very low mileage

Tags:1966, 1966 Cadillac Coupe deVille, For Sale, Time capsule, Low Mileage, Antique Gold