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SECTION 2
FRAME
INDEX
Page
General Description
2-1
Chevrolet
2-1
Cheveile
'.
2-1
Repair Procedures
2-1
Page
Checking Frame Alignment
2-1
Car Preparation
2-1
Tramming Sequence
2-1
Reference Point Dimensions
2-1
GENERAL DESCRIPTION
CHEVROLET AND CHEVELLE
Frames used on Chevrolet and Cheveile lines are basi-
cally the same, consisting of full length right and left
side members joined laterally by crossmembers. Sev-
eral different frames are used in each line to meet the
various vehicle size and function requirements but the
basic shape for each line remains the same. Differences
between frames in a given line exist only in metal gauge,
part size and numbers of parts necessary to meet the
particular
structural
requirements
of
the models
involved.
CORVETTE
The Corvette frame is a rigid perimeter unit, with five
crossmembers. From the rear kick-up forward, trap-
azoidal shaped, closed side members outline and protect
the passenger compartment. At the cowl area, the side
members curve inward in a sweeping "S" shape, to pro-
vide a sturdy foundation for the engine mounts and clear-
ance for front wheel movement.
From the kick-up
rearward, box-sectioned side rails provide fore and aft
support for the rear axle and suspension. Lateral sup-
port is provided by five variously shaped welded-in
crossmembers, including the front unit, which formerly
was bolted-in.
CHEVY II AND CAMARO
Underbody alignment checking procedures will be found
in the Body Service Manual.
REPAIR PROCEDURES
CHECKING FRAME ALIGNMENT
Vehicles involved in an accident of any nature which
might result in a "swayed" or "sprung" frame should
always be checked for proper frame alingment in addi-
tion to steering geometry and wheel alignment.
CAR PREPARATION
Preparing the car for the frame alignment check in-
volves the following:
1. Place the car on level surface.
2. The weight of the car should be supported at the
wheel locations.
3. A visual damage inspection should be made to elim-
inate needless measuring. Obviously damaged or
misaligned areas can often be located by sight.
TRAMMING SEQUENCE
When checking a frame for alignment in case of dam-
age, the first step is horizontal "X" checking with a
tram from similar given points on opposite side of the
frame.
Frame alignment checks on all models should be made
with the tram points set at the center of each locating
point indicated and the cross bar level to insure
accuracy.
When "X" checking any section of the frame, the
measurements should agree within 3/16". If they do not,
it means that corrections will have to be made.
If a tram gauge is not available, the "plumb bob"
method of checking may be used. To assure any degree
of accuracy when using this method, the vehicle should
be on a level floor.
By using this method, it is only necessary to have a
#
piece of cord attached to an ordinary surveyor's plumb
bob. When measuring the distance between two points,
the free end of the cord should be placed on the reference
point allowing the plumb bob to hang on the floor. A check
mark should be made on the floor just under the tip of
the plumb bob. This operation should be repeated at all
reference points. With these points located on the floor,
they may easily be measured with a rule.
The second step is checking the vertical dimensions
from the datum plane to the points to be trammed. With
the proper settings the tram bar will be on a plane
parallel to that of the frame. The exception to this would '
be when one of the reference locations is included in the
misaligned area; then the parallel plane between the
frame and the tram bar may not prevail. After com-
pletion of the repairs, the tram gauge should be set at
the specified dimension to check the accuracy of the re-
pair operation.
ALIGNMENT REFERENCE POINT DIMENSIONS
Dimensions to holes are measured to dead center of
the holes and flush to the adjacent surface metal.
CHEVROLET CHASSIS SERVICE MANUAL
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