Chevrolet 1977 light duty truck Service Manual page 107

G eneral D e s c rip tio n ........................................................................2A-1
On-Vehicle Service........................................................................... 2A-1
M aintenance and In spectio n......................................................2A-1
U n d erb o d y A lig n m e n t................................................................. 2A-3
Excessive Body D a m a g e .............................................................. 2A-3
Light duty 10-30 Series fram es are of the ladder
channel section riveted type.
Figure 2A-1 thru 2A-4 illustrates typical light duty
truck fram es with crossmembers, body mounts and
suspension attaching brackets. This section also includes
general instructions for checking fram e alignment and
recom m endations on frame repair.
MAINTENANCE AND
INSPECTION
UN D ER B O D Y IN S PE C TIO N
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 reinforcem ent m em b er 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 treatm ent is performed.
U sing a chisel, ensure that the drain provisions in
the floor pan reinforcem ent m em bers are open.
T here 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 o f the
rocker panels, and in the lower rear quarter panels.
FRAM E IN S PE C TIO N
Raise the vehicle on a hoist (preferably a twin-post
type).
Check for obvious floor p an deterioration.
Check for loose dirt and rust around the inside of
the fram e rails, on top and at the ends where corrosion
SECTION 2A
FRAME
C O N T E N T S
U nd erb ody Inspection................................................................ 2A-1
F ram e In sp e c tio n ......................................................................... ■ 2A-1
Fram e A lig n m en t........................................................................... 2A-1
GENERAL DESCRIPTION
ON-VEHICLE SERVICE
The G-Van fram e
outriggers are part o f the underbody assembly which is a
welded unit.
M isalignment o f the underbody can affect door
opening fits and also influence the suspension system,
causing suspension m isalignm ent.
therefore, that underbody alignment be exact to within
1/16" o f the specified dimensions.
may exist in hidden areas. Check especially in the frame
box sections for accumulation of debris.
FRAME A L IG N M E N T
Horizontal fram e checking
tram m ing gauges applied directly to the fram e or by
transferring selected points of measurem ent from the
frame to the floor by means o f a plum bob and using the
floor layout for measuring. Figure 2A-2 or 2A-4 may be
used as a general guide in the selection o f checking
points; however, selection o f these points is arbitrary
d ep e n d in g on accessibility
im portant point to rem em ber is that for each point
selected on one side o f the frame, a corresponding point
on the opposite side of the fram e must be used for
vertical checks, opposite
horizontal checks.
Vehicle Preparation
Points to rem em ber when preparing vehicle for
frame checking:
1. Place vehicle on a level surface.
2. Inspect dam ag ed
misalignment to eliminate unnecessary measuring.
side rails, cross sills and
It is essential,
can be m ade with
and convenience. An
and alternate sides for
areas for obvious frame