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1976 Cadillac Fleetwood Brougham Rear Self-Leveling System

Started by Wayne Johnson, December 13, 2021, 03:40:39 AM

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Wayne Johnson

I just purchased a 1976 Cadillac Fleetwood with 65,000 miles. The self-leveling rear suspension is not working. I have read that there is a conversion kit available. Does anyone know where I can get it? Also, I have seen 1976 Fleetwood springs being sold with the option of adding 2 inches more height. Even though the current air shocks are not working, the car's rear end is not bouncing. The rear is sagging, though. What will happen if I add two more inches to the springs but, leave everything else alone?

Big Fins

I replied in the old thread that you posted in. Maybe Bruce can move the post and bury the old thread again.
Current:
1976 Eldorado Convertible in Crystal Blue FireMist with white interior and top. (Misty Blue)
1969 Fleetwood Brougham in Chalice Gold FireMist with matching interior and top. (The Old Man) SOLD!

Past and much missed:
1977 Brougham de Elegance
1976 Eldorado Convertible
1972 Fleetwood Brougham
1971 Sedan de Ville
1970 de Ville Convertible
1969 Sedan de Ville
1959 Sedan deVille

The Tassie Devil(le)

G'day John,

Old thread dead and buried.

But, sadly, you will have to retype your replies, as I couldn't figure out how to join both, and separate the old parts without losing the whole lot.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

James Landi

Hi Wayne,

I provide you with the condensed, "Readers' Digest" answer.  You're correct --- the old vacuum actuated system is no longer fixable---it had a "service life," parts needed to be replaced, they're not available.  "Helper springs" makes sense, and they provide a good average height to keep the car level.  A quick less expensive workaround , especially given the low mileage, is to purchase a schrader valve, mount it under the rear of the car, and run new flex hoses directly to a tee and to the schrader valve, and inflate with a tire compressor.  At around 60 pounds, you'll get a "nice" height, and you'll get an improved ride and better view of traffic out of the rear window .  Down side of this approach: without an "over pressure" reflief valve, you'll blow out one of the hose connections when and if you hit a pot hole hard, and you'll also need to inflate the air shocks on occasion, as they do bleed compressed air over time.   It used the schader valve approach in my '72 Eldo, and it worked great.   I've also used an electric air compressor, and mounted an under dash momentary switch and pressure gauge---provided me with a nice convenience.      Hope this helps Wayne,  James

TJ Hopland

The 'brains' of this operation is the level sensing valve near the rear axle.  Those as far as I know are pretty reliable but its possible that we never have to find out if they are long lasting because the compressors fail.   

The compressor works more or less like the one you could have in your garage.   Its has a power source which in the OE case is vacuum and when ever it has 'power' it does its best to maintain a preset level of pressure in the tank.   

The leveling valve at the rear is doing the work.  If the car is high a port opens that vents some air out of the shocks.   If the car is low a port opens to connect the line from the compressor tank to the shocks.   It also has a mechanical buffering system in it so that its not constantly trying to adjust the pressure based on every little bump you hit.

This all means in theory you could buy some sort of 12v powered compressor that has its own tank and pressure switch and the rest of the system would never know the difference.  All it wants is a source of high(ish) pressure air.

In 78 when Cadillac went to electric compressors they did it differently.   They put an electronic level sensor assembly that included an electronic module at the rear axle.  This sensors output would either operate the compressor to add air to the shocks or open a dump valve at the compressor.  78-90ish the compressor was under the hood.  Later they decided on the frame near the rear wheel was a good location for it.   The main failure point of these was the sensor module.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

David King (kz78hy)

I think Lars Kneller repairs these.   I have 3 pumps somewhere, 2 different sizes of cans as I remember.  They would be cores.
David King
CLC 22014  (life)
1958 Eldorado Brougham 615
1959 Eldorado Brougham 56- sold
1960 Eldorado Brougham 83- sold
1998 Deville d'Elegance
1955 Eldorado #277
1964 Studebaker Commander
2012 Volt
CLCMRC benefactor 197

Director and Founder, Eldorado Brougham Chapter
Past President, Motor City Region

Rare Parts brand suspension parts Retailer via Keep'em Running Automotive

Matti R

Best regards,
Matti
CLC #33333
67 DeVille convertible Sudan beige
79 Seville
64 Sedan DeVille
66 Calais Coupe

Wayne Johnson

Thank you guys.

I think I'm going to install air shocks with a built-in pump and air pressure control as I did with my 1995 DeVille. The one on my '95 does leak but, with the built-in pump, it is manageable and stays at what pressure I set it to for 2-3 days. When it gets cold, I notice that it loses more air than when it's hot outside.

By the way, Henry Martyn LeLand was my 6th cousin. William Durant was also a 6th cousin.

I guess I have Cadillac in my blood. :)

cadillacmike68

Quote from: Wayne Johnson on December 19, 2021, 02:32:49 PM
Thank you guys.

I think I'm going to install air shocks with a built-in pump and air pressure control as I did with my 1995 DeVille. The one on my '95 does leak but, with the built-in pump, it is manageable and stays at what pressure I set it to for 2-3 days. When it gets cold, I notice that it loses more air than when it's hot outside.

By the way, Henry Martyn LeLand was my 6th cousin. William Durant was also a 6th cousin.

I guess I have Cadillac in my blood. :)

Boyle's law in effect. Same with your tire pressure which is undoubtedly lower than it was 1-2 months ago.
Regards,
"Cadillac" Mike

dochawk

Quote from: Wayne Johnson on December 19, 2021, 02:32:49 PM
By the way, Henry Martyn LeLand was my 6th cousin. William Durant was also a 6th cousin.

I'm assuming that either that's about four five times removed, or that you recall and possibly fought in the Spanish American War . . .

;D

[6th cousins share a common ancestor seven generations back, and fifth removed of a sixth cousin would be five generations down the line from the first cousin]

1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

Cape Cod Fleetwood

Detroit Spring sells the correct spring to keep the car level, change them all while you're there.
Put on the correct Monroe shocks and be done with this issue for ever.
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all