Chevrolet Silverado / GMC Sierra. Service manual - part 1294

Fig. 92: Creating Backing Plate 
Courtesy of GENERAL MOTORS CORP. 

2. Create a 50 mm (2 in) (1) backing plate from the unused portion of the service part. Trim the backing 

plate as necessary to fit behind the sectioning joint where there is no reinforcement. 

 

2008 Chevrolet Silverado 1500 

2008 ACCESSORIES & EQUIPMENT Collision Repair - - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & 

Silverado

  

Fig. 93: Drilling Plug Weld Holes 
Courtesy of GENERAL MOTORS CORP. 

3. Drill 8 mm (5/16 in) plug weld holes along the sectioning cut on the remaining original part (2). Locate 

these holes approximately 13 mm (1/2 in) from the edge (1) and spaced 40 mm (1 1/2 in) apart. 

 

2008 Chevrolet Silverado 1500 

2008 ACCESSORIES & EQUIPMENT Collision Repair - - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & 

Silverado

  

Fig. 94: Drilling Plug Weld Holes 
Courtesy of GENERAL MOTORS CORP. 

4. Drill 8 mm (5/16 in) plug weld holes in the service part as necessary in the locations noted from the 

original panel and along the sectioning cut. 

IMPORTANT: If the location of the original plug weld holes cannot be determined, space 

the plug weld holes every 40 mm (1 1/2 in) apart.

 

2008 Chevrolet Silverado 1500 

2008 ACCESSORIES & EQUIPMENT Collision Repair - - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & 

Silverado

  

Fig. 95: Plug Weld Holes & Welding Backing Plate 
Courtesy of GENERAL MOTORS CORP. 

5. Prepare all attachment surfaces, as necessary.  

6. Apply GM-approved Weld-Thru Coating or equivalent to all mating surfaces. Refer to Anti-Corrosion 

Treatment and Repair .  

7. Fit the backing plate (3) halfway into the sectioning joint, clamp and plug weld to the vehicle. 

 

2008 Chevrolet Silverado 1500 

2008 ACCESSORIES & EQUIPMENT Collision Repair - - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & 

Silverado