Re: [VACList] Towing Question

["Kevin D. Allen" <kallen@xxxxxxxxxxxxxxx>]

Greetings David!

I share your interest in older Cadillacs and Airstreams.  My current project
is to prepare my '75 Cadillac Eldorado Convertible to tow my '78 Argosy
Minuet - - the '64 Overlander is just too close to its trailer tow limit of
6,000 pounds.

I don't believe that Cadillac ever rated their DeVilles to tow more than
7,000 pounds; and I know the Eldorado (at least 1970 to 1978) never had more
than a 6,000 pound trailer tow rating.  There are a few things to be aware
of when considering this option:

1.)  If your '71 Cadillac doesn't have the special hardened valve seats for
unleaded fuel, you will quickly burn the valves when adding the stress of
towing and burning unldeaded fuel.  The motor can be retrofitted with
hardened valve seat inserts, but be prepared for some expense - - when I had
the process performed on my '65 Dodge Coronet's 383 c.i./335 h.p. V8 the
cost was in excess of $1,500 and this was nearly twenty years ago.

2.)  It will only be by a stroke of luck if you would happen to find a
trailer hitch dealer with an NOS hitch that will fit a 1971 Cadillac.  It
took me several weeks and numerous telephone calls before I was able to find
a welder who was willing to fabricate and install a Reese Class III/IV
weld-up receiver hitch package - -  many welders now shy away from this
business as a result of product liability issues.

3.)  I wouldn't worry about adding overloads to your springs.  The preferred
method is to replace the original springs with new.  My local Midas Muffler
shop was able to get heavy duty Cargo-Coil replacement springs for my '75
Eldorado and indicated that similar replacements were available for most
Cadillacs from 1970 on.  The new springs will improve the ride, handling,
and will restore proper ride height.  If your Cadillac has the automatic
load-leveling shocks, you will need to carefully read the owner's manual
before hooking up your weight distributing hitch as there is a very definite
procedure to be followed to prevent damage to the suspension and to insure
proper operation of the load equalizer hitch.  When I had my Eldorado
prepped, I had larger capacity rear load leveler shocks installed to replace
the ancient originals; and had heavy duty gas filled shocks installed on the
front.

4.)  I would strongly suggest a new heavy duty four-row core radiator (this
will almost assuredly need to be a semi-custom unit as the only stock OEM
unit that my local radiator shop had available was the three row core).  It
seems like these early to mid 1970s Cadillacs like to run a bit warm when
traveling solo, and the added cooling capacity is wonderful under all
conditions.  The stock radiator (even after a thorough professional
cleaning) had a tendency to boil over when the car was driven solo in hot
summer weather - - the larger capacity radiator solved this quite nicely.

5.)  When considering a transmission oil cooler, I would suggest that you
would want at least a 12,000 GCVWR rated cooler or quite possibly a 16,000
GCVWR cooler.  In my application, I utilized a 12,000 GCVWR cooler as my
Minuet weighs less than 3,500 pounds fully loaded.

6.)  You will probably find that the rear end gearing may not be totally
appropriate for towing.  A 2.73 rear differential ratio was standard.  At
the time, I believe that 3.23, 3.90 and 4.10 were optionally offered for
trailer towing in the DeVille series.

I am sure that your Sovereign will be pushing the factory towing limit on a
DeVille, but it might be workable.  If your Cadillac is an Eldorado,
however, I believe that you will find that it is too much trailer for the
car as the final drive gearing is quite expensive to alter and is one of the
biggest drawbacks to towing with the Eldorado.

 Good luck with your project!

Kevin Allen
WBCCI/VAC #6359
1964 Overlander International/1999 GMC K2500 Suburban
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado (Towcar-In-Training)