Chevrolet 1980 Light Duty Truck Service Manual page 105

General Description........................................................................... 2A-1
On Vehicle Service............................................................................. 2A-1
Light duty 10-30 Series frames are of the ladder channel
section riveted type.
Figure 2A-1 thru 2A-4 illustrates typical light duty
truck frames with crossmembers, body mounts and
suspension attaching brackets. This section also includes
general instructions for checking frame alignment and
recommendations on frame repair.
MAINTENANCE AND INSPECTION
UNDERBODY INSPECTION
Raise the vehicle on a hoist (preferably a twin-post
type).
Check for obvious floor pan deterioration.
Check for loose dirt and rust around the inside of the
floor pan reinforcement member access holes. This is the
first indication that corrosion may exist in hidden areas, and
that repairs might be required before the final cleaning and
protective treatment is performed.
Using a chisel, ensure that the drain provisions in the
floor pan reinforcement members are open.
There are drain holes in the body side panels also.
These holes can be opened by using a punch or drift. The
side panel drain holes are in the rear section of the rocker
panels, and in the lower rear quarter panels.
FRAME INSPECTION
Raise the vehicle on a hoist (preferably a twin-post
type).
Check for obvious floor pan deterioration.
Check for loose dirt and rust around the inside of the
frame rails, on top and at the ends where corrosion may
SECTION 2A
FRAME
CONTENTS
Maintenance and Inspection..................... ...................................... 2A-1
Underbody Inspection.................................................................... 2A-1
Frame Inspection........................................................................... 2A-1
Frame Alignment............................................................................. 2A-1
Underbody Alignment..................................................................... 2A-4
Excessive Body Damage.................................................................. 2A-4
GENERAL DESCRIPTION
ON-VEHICLE SERVICE
The G-Van frame side rails, cross sills and outriggers
are part of the underbody assembly which is a welded unit.
Misalignment of the underbody can affect door
opening fits and also influence the suspension system,
causing suspension misalignment. It is essential, therefore,
that underbody alignment be exact to within - 1/16 in.
(1.9mm) of the specified dimensions.
exist in hidden areas. Check especially in the frame box
sections for accumulation of debris.
FRAME A LIG N M EN T
Horizontal frame checking can be made with tramming
gages applied directly to the frame or by transferring
selected points of measurement from the frame to the floor
by means of a plum bob and using the floor layout for
measuring. Fig. 2A-2 or 2A-4 may be used as a general guide
in the selection of checking points; however, selection of
these points is arbitrary depending on accessibility and
convenience. An important point to remember is that for
each point selected on one side of the frame, a corresponding
point on the opposite side of the frame must be used for
vertical checks, opposite and alternate sides for horizontal
checks.
Vehicle Preparation
Points to remember when preparing vehicle for frame
checking:
1. Place vehicle on a level surface.
2. Inspect damaged
misalignment to eliminate unnecessary measuring.
FRAME 2A-1
areas for obvious frame
LIG H T T R U C K SER V IC E M ANUAL