5
Before you begin work with your Body
Straightener, it is vital that you determine how
extensive the damage is.
To do this, get the car up off the ground, lie under
the structure and thoroughly inspect.
Measurements should be taken to see how far
the damaged sections are out of alignment.
These measurements can be made with a
Trammel Gauge, or a tape measure.
A simple method is to drop a plumb bob from
identical points from either side of the chassis,
marking them, in chalk, on the floor below.
Measure various points diagonally.
A perfect chasis will produce identical readings,
whereas a difference in measurement indicates
the body/chassis has moved in some way.
From these measurements, determine where and
how the distortion has occurred.
Remember, it is your job to restore the damaged
sections back to the original factory
specifications. Therefore, it is important to work
from chassis dimension charts, so that you know
exactly what the original dimensions were. There
is no point in making a pull if you do not know
how far you can pull and when to stop. Take time
to examine the damage, note the direction of
the impact, and then plan your pull. Proper
planning will save you time when it comes to
actual pulling.
HOW TO MEASURE THE EXTENT OF THE DAMAGE
The idea of straightening chassis damage is to
exert a force in the reverse direction to that of
the collision impact.
Your work will be made much easier by taking off
any interfering parts (wheels, bumpers grills, etc.),
so that you can see as well as get at the damage.
In cases where parts are unrepairable and must
be replaced, they should be removed first! In front
end damage it may become necessary to
remove upper or lower control arms, anti-roll bars,
etc. to eliminate excessive spring back.
Where major body damage occurs, rough out
the body metal first. DON’T REMOVE BODY BOLTS
unless absolutely necessary. Do as much body
roughing out as you can whilst working on the
chassis.
If possible, correct any body damage in unison
with chassis straightening. This will save time and
effort and will make it easier to align the body
with the chassis.
The chassis and body should always be
overcorrected to allow for spring-back.
Hammering or heating the metal will help relieve
the stress and help eliminate excessive
springback.
When there is no clearance between the chassis
and the body, the floor may be pried up to allow
anchoring of the chain or an opening in the floor
made that can later be welded shut. A prefered
method is to weld a plate to the chassis from
which pulls can be made. The plate may later
be removed.
SAG
To repair SAG put the main beam of the Body
Straightener under the car and chain the chassis
to the beam. Place a Hand Jack between the
beam and the chassis at the center of the SAG
area and jack upward whilst also pulling as shown
in the sketch below:
HOW TO REPAIR CHASSIS DAMAGE
Always use a combination of push AND pull when
correcting sag. If you do not, you may end up
with one chassis rail shorter than the other. It both
rails are sagged, straighten one at a time, then
check with gauges to see that the chassis is back
in line. If it isn’t repeat this process.
Keep the hold-down chains on the chassis as far
apart from the jack as you can. This will make
straightening easier. Where there are bad
buckles, heat the chassis.
CAUTION!
USE ONLY THE HYDRAULIC SET SUPPLIED WITH YOUR BODY STRAIGHTENER.
Use of different Hydraulic Set or handle may damage unit.
In such cases warranty claims will be void.
