Text and Photography C.
Asaravala, J. Mikelonis
Introduction
Have you ever wondered
why cars lose their "new car" feel? The steering becomes
less responsive, the handling feels soft, and the once
quiet and smooth ride now squeaks and rattles like a dime
store shopping cart? The culprit is rubber. Also known
as natural rubber, nitrile, or NBR. Nitrile bushings,
mounts, and seals are used throughout the chassis to dampen
shock, vibration and noise. Unfortunately nitrile wears
with time and use. Constant absorption of energy, shear,
and exposure to sun, ozone, UV, as well as chemicals,
results in a lack of resilience and loss of performance.
Nitrile wears with time and
use. Constant absorption of energy, shear, and exposure
to the environment results in a lack of resilience
and loss of performance. |
Worn nitrile suspension and
steering components lead to accelerated wear of hard parts
such as bearings and ball joints. The logical alternative
to natural rubber is polyurethane or "urethane".
Not to be mistaken with plastic, urethane is part of the
elastomeric family called "rubber." However,
urethanes have an unusually high load bearing capacity
relative to any other rubber material. They also have
deflection and recovery capabilities possessed by no other
plastic or metal.
Why then is polyurethane not more widely used in production
chassis' and suspensions? After all it was developed before
1940. Well, to the dismay of Ford enthusiasts like ourselves,
automotive manufacturer's are responsible for meeting
the requests of the mainstream buying public with the
greatest value for the dollar. For this reason, technologial
advances sometimes go unincorporated into the automobiles
we purchase in order to appeal to the masses and maintain
low manufacturing costs. Automotive enthusiasts like ourselves
suffer the consequences of a mass market that chooses
a "smooth ride" over handling or "low cabin
noise" to firm shifts and greater throttle response.
Additionally, cars are not typically designed to last
more than ten years. Most Ford hobbyists drive cars that
are older than 10 years and a number of our project cars
were built before polyurethane was widely used.
Before we get into installing Polyurethane, take a few
moments to gain a better understanding of the superior
and unlikely physical attributes of this killer material.
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In This Article:
We cover the benefits of replacing worn nitrile
rubber  suspension
components on your car. We'll demonstrate on our
1988 Mustang LX using Energy Suspension's Hyper
Flex Polyurethane kit. See
Kit contents.
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Polyurethane
basics and advantages over nitrile rubber.
Replacing
sway bar bushings, endlinks, and rack and
pinion bushings.
Replacing
rear control arm bushings and rear coil
spring isolators. 