IML: Torsion Bar Front Suspension

["Burton Bouwkamp" <northburt@xxxxxxxxxxx>]

I was a motor and chassis engineer at Chrysler from 1951 to 1962. We 
(Chrysler) had a problem in northern climates with broken torsion bars on 
1957 models after one to two years of service. It was caused by corrosion of 
the surface of the torsion bar from dirt/salt/moisture accumulating around 
the bar at the socket cavities (either end). In 1957 we had not adequately 
sealed the bar ends from exposure and accumulation of this corrosive mud. 
The problem was the most serious in communities that used salt for snow and 
ice removal. (We sealed these cavities in 1958, 1959, etc.)  Until the seals 
were available we told our service people to pack these cavities with 
grease.

The corrosive action of the mud attacked the highest stressed part of the 
bar - the outside surface - causing stress risers which lead to fracture of 
the bar. A mystery to many of us was why almost all failures happened while 
the car was parked overnight - and not while the car was in motion. (It must 
have had something to do with the ambient temperature change overnight.)

Burt Bouwkamp

----- Original Message ----- 
From: "Ernie Stepney" <estepney@xxxxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Saturday, July 22, 2006 5:01 PM
Subject: RE: IML: Torsion Bar Front Suspension


Ah yes; broken torsion bars, had an Astro AWD towed in last week with
that instant lowering job. Broke while parked overnight.

Ernie


-----Original Message-----
From: mailing-list-owner@xxxxxxxxxxxxxxxx
[mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of aeyn
Sent: Friday, July 21, 2006 10:20 PM
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: Re: IML: Torsion Bar Front Suspension

What Rolland has to tell about the Torsion bar is great and very
interesting.  Has any one here seen a broken T-Bar.  I have and
it isn't a pretty sight.  It is EXTREMELY hard to break them.

By The Way, I recently bought the 1975 Dealer Trim and Accessory
for initial inventory (not hard bound.)  I discovered that my
Imperial is Moon Dust Metallic (LL5), not Aztec Gold as I had
understood.  It has a cream/camel coloured leather interior.  How
can I post photos on the web site.

Æyn & Patrick

--- Dr David George Briant <drdgb@xxxxxxx> wrote:

> Useful interesting comments by Rolland.  Thank you.
>   ----- Original Message ----- 
>   From: RWestra@xxxxxxx
>   To: mailing-list@xxxxxxxxxxxxxxxx
>   Sent: Friday, July 21, 2006 5:16 PM
>   Subject: Re: IML: Torsion Bar Front Suspension
>
>
>   I worked at Chrysler Central Engineering from 1959 to 1961
> when the "Torsion-Aire" suspension was just two years on the
> market.  The stated reasons for going to a torsion bar spring
> were two-fold as I recall:
>   1.  Packaging - lower front profile for the 1957 cars.  It
> was easier to package a long bar parallel to the frame than try
> to tuck a coil spring between the upper and lower control arms.
>
>   2. Adjustable suspension height to avoid matching front coil
> springs at the plant.
>
>   Along with the torsion bar spring a new suspension geometry
> was introduced to improve handling and control front end "dive"
> when braking.  This had nothing to do with the choice of spring
> configuration but it may have been easier to design in the
> desired geometry without a coil spring to restrict packaging.
>
>
>   As I recall the torsion bar spring rate was higher than the
> coil spring.   This stiffer ride improved handling.  To
> compensate for the stiffer ride a new 14" tire was introduced.
> This provided the "Aire" component of the "Torsion-Aire" ride.
>  (more than likely invented in the marketing department).  The
> new suspension was a good one and probably the most advanced of
> its time.  It represented probably the best ride/handling
> compromise of its time but this was due mostly to the geometry
> and tire selection and probably had little to do with the
> spring configuration.
>
>   I'm not sure but as I recall the suspension design looked a
> lot like the Citrone at the time.  As for the torsion bars
> influence on ride and handling it really didn't.  The
> conventional wisdom at Chrysler was:  whether you take a piece
> of spring steel and stretch it into a rod or coil it into a
> spring it is still a spring and like all springs must obey
> Hookes law.
>
>   This is my 2 cents worth on the Torsion-Air ride of the 50's
> at Chrysler.  My memory of events nearly 50 years ago is not
> perfect but this is my recollection.
>
>   When I worked in Chassis research a rear torsion bar car was
> prototyped (a 1959 Plylmouth) and development work continued
> for 2 to three years but it never made it to production.  The
> comments were: "the leaf spring, with its multi functions, is
> just darn hard to replace.
>
>
>                               Rolland Westra



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