1997/98 Chevrolet Corvette
Collision Repair
3-9
Rail-Underbody Side Assembly
Overlap
Minimum: 50 mm
Maximum: 100 mm
Fig.␣ 3.18 — Offset Lap Joint
Fig.␣ 3.19 — Modify Rail for Offset joint Repair
Overlap
Min. 50 mm (2 in)
Max. 100 mm
(4 in)
Fig.␣ 3.20 —
3
Measure the service rail for sectioning,
remember that the overlap of the service
part and the original rail can be as large as
100mm (4 inches). This 100mm (4 inch)
tolerance provides an area to install plug
welds on the sides of the rail, as well as allow
for adjustment during the installation
process.
4
Mark the location and cut the service rail as
square as possible.
5
Modify the portion of rail left on the vehicle
to accept the service part. This is done by
cutting 75mm (3 inch) slots in two opposite
corners of the rail Fig.␣ 3.19. Then slightly pry
up the slots to accept the service part. The
slots allow the service part to overlap the
existing rail to form a lap surface for welding.
Notice: Open the slots to create additional
adjustment if necessary. Do not exceed
100mm (4 inch) overlap for offset lap-joint
repairs.
6
Drill three 8mm (5/16 inch) holes through
each of the sides and two holes each in the
top and bottom surface for plug welding, as
in Fig.␣ 3.20.
7
Install the modified service part to form the
offset lap-joint. Align the service part using
three dimensional measurements.
8
Plug weld along the overlap. Also, stitch weld
along the entire sectioning joint. Make 50mm
(2 inch) welds on all four sides of the rail.
Re-check the rails for proper dimensions.
Then go back and complete the stitch welds.
This will create a solid joint with minimal heat
distortion.
9
Clean and prepare welded surfaces, blend in
exposed side of lap joint with Goodwrench
Structural Bonding Epoxy (GM P/N
12345726), or an equivalent structural repair
material. Apply as necessary to achieve
original appearance.
Important: Prior to refinishing, refer to
GM P/N 4901 Refinish Manual for
recommended products.
10
Apply approved anti-corrosion primer.
Notice: DO NOT top-coat any bonding
surface.
11
Clean and prepare all bonding surfaces as
necessary.
(Refer to SMC Repair Procedures.)