How to install Early Classic's Trailing
Story and Photography by Matt
The advantages of the trailing arm system
over a leaf-spring design are many. The trailing arm suspension makes for a
much better handling vehicle than those with leaf springs (just ask the NASCAR
guys), but the arms themselves had a not-so-hidden design flaw.
are made up of two stamped pieces that are riveted together. The problem can be
that during the normal operation of the truck, the two pieces can begin to
separate. This is a two-fold problem. One is that there is the possibility of
the pieces separating enough that the holes through which the U-bolts are
attached become dangerously loose. When that happens, much like an our-of-round
tire, the action of the U-bolts moving back and forth within the holes
exacerbates itself. This action could begin to destroy the arm. Another issue
is that with the U-bolts coming loose in their mounting holes, the handling of
the truck will become sloppy as the rearend wanders. This will especially be
evident during cornering.
To combat this, Dave Clark of Early Classic
Enterprises in Fresno, California, offers a Trailing Arm Reinforcement Kit. The
idea behind the kit is to weld 1/8-inch steel plates to the upper and lower
edges of the trailing arm. These will act to integrate the two pieces of the
arms into one. In addition to simply preventing the two pieces from separating,
the plates will also greatly add to the overall rigidity of the arm by
preventing the arms from twisting during hard driving, thus improving the
The Early Classic kit not only supplies the plates,
but also includes new bushings and U-bolts. With the original arms being 40
years ld, the bushings are probably thrashed, so replacing these is a must.
Another important safety consideration is to occasionally replace the U-bolts
that hold the axle tube in place.
With the exception of the time it
takes to weld the plates on, this is a simple modification, and one that is
important to the safe operation of '67-'72 Chevy and GMC trucks. Follow along
as we demonstrate how to install the Early Classic Trailing Arm Reinforcement