Lower Rail Sectioning left

Important: If the damage exceeds the recommended area for sectioning and the rail cannot be straightened, the complete rail must be replaced.

Important: The additional 10 mm (13/32 in) metal measurements will be used to create a flange for welding the new service part to vehicle.

1. On the top of the rail, locate the last cut-out square (1). From the front edge of square, measure forward 47 mm (1 7/8 in) and scribe a line.
2. Add 10 mm (13/32 in) and scribe a second line. The second line 57 mm (2 ¼ in) is cut location.



3. On the inboard side of the rail, locate hole (1). Measure forward 54 mm (2 5/32 in) and mark location. Scribe a straight line on rail.
4. Measure forward 10 mm and scribe a second line. the second line 64 mm is the cut location.



5. On the outboard side of the rail, locate where brake line bolts to rail.
6. Remove bolt and bracket.
7. At larger hole, pull tape measure tight from forward edge of hole (2) and mark a line at 416 mm (16 in).
8. Scribe a line with a straight edge. Make it as square as possible to inboard and top rail markings.
9. Add 10 mm (13/32 in) and scribe a second line. The second line is the cut location (426 mm /16 ¾ in).



10. Make certain all three sides are aligned.
11. Cut through all three sides of rail.
12. On the bottom of the damaged rail (1), scribe a line from the outboard to the inboard cut locations and cut remainder of the rail from the vehicle.
13. Remove the damaged section of the rail.

1. On the original rail, cut and remove 10 mm (13/32 in) of the outboard (1) and downward (2) turned flanges of the rail.
2. Cut 10 mm (13/32 in) gaps along the corners of the original rail.
3. Step the top, bottom and side tabs inward (3) to allow the service part to fit over the original rail.
4. Clean and prepare mating surfaces as necessary.

1. Position the service part over the original rail.
2. Align and check fit with three-dimensional measuring.



3. Stitch weld along the entire sectioning joint.
4. Make 25 mm (1 in) welds along the seam with 25 mm (1 in) gaps between.
5. Go back and complete the stitch weld to create a solid weld joint with minimal heat distortion.
6. Clean and prepare all welded surfaces.

Important: Prior to refinishing, refer to GM 4901MD-99 Refinish Manual for recommended products. Do not combine paint systems. Refer to paint manufacturers recommendations.

7. Prime with two-part catalyzed primer.
8. Apply sealers and anti-corrosion materials as necessary.
9. Install all related panels and components.

Lower Rail Sectioning right

Important: If the damage exceeds the recommended area for sectioning and the rail cannot be straightened, the complete rail must be replaced.

Important: The additional 10 mm (13/32 in) metal measurements will be used to create a flange for welding the new service part to vehicle.




1. On the top of the rail, locate the last cut-out square.
2. From the front edge of the square (1), measure forward 17 mm (11/16 in) and scribe a line.
3. Add 10 mm (13/32 in) and scribe a second line. The second line (27 mm/ 1 3/32 in) is the cut location.
4. On the inboard side of the rail, locate fixturing hole (2). Measure forward 170 mm (6 ¾ in) and scribe a line to mark location.
5. Add 10 mm (13/32 in) and scribe a second line. The second line (180 mm/ 7 1/8 in) is the cut location.



6. On the outboard side of the rail, locate where the brake line bolts to the rail.
7. At larger hole, pull tape measure tight from forward edge of the hole (1) and mark a line at 402 mm (15 ¾ in).
8. Scribe a line with a straight edge to make it as square as possible to inboard and top rail markings.
9. Add 10 mm (13/32 n) and scribe a second line. The second line (412 mm/ 16 ¼) is the cut location.
10. Make certain all three sides are aligned.
11. Cut through all three sides of the rail.



12. On the bottom of the damaged rail (1), scribe a line from outboard to inboard cut locations and cut remainder of the rail from the vehicle.
13. Remove the damaged section of the rail.

1. On the original rail, cut and remove 10 mm (13/32 in) of the outboard (1) and downward (2) turned flanges of the rail.
2. Cut 10 mm (13/32 in) gaps along the corners of the original rail.
3. Step the top, bottom and side tabs inward (3) to allow the service part to fit over the original rail.
4. Clean and prepare mating surfaces as necessary.

1. Position the service part over the original rail.
2. Align and check fit with three-dimensional measuring.



3. Stitch weld along the entire sectioning joint.
4. Make 25 mm (1 in) welds along the seam with 25 mm (1 in) gaps between.
5. Go back and complete the stitch weld to create a solid weld joint with minimal heat distortion.
6. Clean and prepare all welded surfaces.

Important: Prior to refinishing, refer to GM 4901MD-99 Refinish Manual for recommended products. Do not combine paint systems. Refer to paint manufacturers recommendations.

7. Prime with two-part catalyzed primer.
8. Apply sealers and anti-corrosion materials as necessary.
9. Install all related panels and components.