The cleanup of the undercarriage of my low mileage, all original 74 Coupe deVille turned into a big project, which almost took a year instead of only a few weeks.
I had some really bad luck with non sticking paint, undercoating reacting with the paint and shops not doing their job right…
The goal of this project was to remove all the surface rust, clean everything up and paint it in the correct colors again. For the ultimate, invisible protection I applied transparent undercoating from "Timemax" and transparent stone guard to the wheel housings. It was very important for me that the car looks as original and as perfect from the underside as the rest of it.
You can read reports about what I had to do by clicking here. You can also see all the restoration pictures in this gallery.

The undercarriage restoration project involved the following things:

• Removed some of the surface rust with rust remover gel.
• Had the undercarriage dry ice blasted and cleaned
• Removed all the surface rust with rust remover gel and liquid
• Cleaned the undercarriage with wire brush to strip bad paint down to bare metal
• Fully detailed the drive shaft
• Repainted the brake drums and fully detailed them with original factory markings.
• Had the rust free undercarriage painted in a paint shop in original black and brown with epoxy paints.
• Had the edges of the lower body parts painted as well in Persian Lime
• Found out that the new paint on undercarriage did not stick…
• Removed all the paint again with sandblasting and dry ice cleaning
• Repainted the undercarriage in the correct colors once again in the paint shop
• Applied transparent undercoating
• Applied transparent stone guard to wheel-housings
• The stone guard coating reacted with paint underneath
• Had another shop remove the paint from the wheel-housings again, as I did not want to do it myself for another time.
• This shop repainted the wheel housings and coated them with transparent undercoating and stone guard once again.
• I was not satisfied with their work so they had to re-do it.
• They sandblasted the wheel housings once again to get everything off to bare metal to be able to start all over once again.
• The restoration shop repainted the wheel housings and coated them with transparent undercoating and stone guard for the third time.
• I finally was satisfied with their work and took over again to detail all the splash guards and put everything back together.
• De-rusted the inner sides of the fender skirts and repainted them.

Other things I did on the 74 during this project:

• Repaired seat back release (3 times)
• Repaired the transmission shift dial indicator which was stuck in “L“ position.
• Replaced some of the plastic headlight adjusting parts which were broken.
• Fabricated license plate holders for Austrian plates.
• Repaired front ashtray mechanism which was stuck.
• Fixed loose left outer rear view mirror.
• Fixed a hole in the exhaust. (Temporary fix before I will replace the still original system which was installed in 1974)
• Replaced numerous burnt bulbs inside and outside of the car.
• Replaced AC compressor as bearing and clutch was shot.
• Repaired clock .
• Repaired radio.
• Replaced all speakers.
• Replaced heater core.
• Replaced front center bumper ends.
• Adjusted grill which was misaligned by the factory.
• Restored battery tray.
• Adjusted doors as they did not close well.
• Repaired door striker on passenger side.
• Replaced door bumper rubber.
• Installed new reproduction - correct heater hoses.
• Flushed cooling system.
• Changed oil.
• Changed shocks front and back.
• Changed stabilizer link and rubber.
• Replaced incorrect lug nuts.
• Changed lighting system to Austrian standards to get it road legal for the inspection.
• Replaced hood ornament.
• Replaced panel in dash.
• Sandblasted and repainted valve covers.
• Repaired washer fluid sensor.
• Replaced antenna.
• Fully detailed the paint and interior.
• Polished the windshield with glass polish.
• Painted oil pans.
• Painted fuel tank.
• Touched up some small stone chips
• Perfectly removed dents on the roof which happened during shipping of the car from the USA to Europe
• Tuned carburetor to factory specs

I´m sure that I have already forgotten some details - unfortunately I often forgot to take pictures, so I cant document everything with pictures…

The various stages of this project
The re-painted wheelhousings. There are a few coats of "Timemax transparent undercoating" and "Timemax Body transparent" - a stone guard applied to protect the paint underneath.This stuff is great and also almost invisible.

The re-painted wheelhousings. There are a few coats of "Timemax transparent undercoating" and "Timemax Body transparent" - a stone guard applied to protect the paint underneath.This stuff is great and also almost invisible. You can also see the detailed splash guards back in place.
The re-painted wheelhousings. There are a few coats of "Timemax transparent undercoating" and "Timemax Body transparent" - a stone guard applied to protect the paint underneath.This stuff is great and also almost invisible. You can also see the detailed splash guards back in place.
I removed all the rust inside the fender skirts as well and painted them afterwards to protect them. I also undercoated them with transparent undercoating as well.
I used tar remover to clean the inside of the fender skirts which still had some factory applied undercoating on them.
This is how the rest of the underside of my 74 is looking now. I painted everything in the correct colors and protected it with transparent undercoating afterwards.

Tags:1974, 1974 Cadillac Coupe DeVille, 1974 Cadillac Repair Tip, Restoration, Underbody, Undercarriage, Undercoating