Removal Procedure
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.
- On the top of the rail,
locate the last cut-out square.
- From the front edge of the square (1), measure forward 17 mm
(11/16 in) and scribe a line.
- Add 10 mm (13/32 in) and scribe a second line. The
second line, 27 mm (1 3/32 in), is the cut location.
- 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.
- Add 10 mm (13/32 in) and scribe a second line. The
second line, 180 mm (7 1/8 in), is the cut location.
- On the outboard side of
the rail, locate where the brake line bolts to the rail.
- At larger hole, pull tape measure tight from forward edge of the
hole (1) and mark a line at 402 mm (15 ¾ in).
- Scribe a line with a straight edge to make it as square as possible
to inboard and top rail markings.
- Add 10 mm (13/32 in) and scribe a second line. The
second line, 412 mm (16 in), is the cut location.
- Make certain all 3 sides are aligned.
- Cut through all 3 sides of the rail.
- 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.
- Remove the damaged section of the rail.
Service Part Preparation
- On the original rail,
cut and remove 10 mm (13/32 in) of the outboard (1)
and downward (2) turned flanges of the rail.
- Cut 10 mm (13/32 in) gaps along the corners of the
original rail.
- Step the top, bottom and side tabs inward (3) to allow
the service part to fit over the original rail.
- Clean and prepare mating surfaces as necessary.
Installation Procedure
- Position the service part over the original rail.
- Align and check fit with 3-dimensional measuring.
- Stitch weld along the
entire sectioning joint.
- Make 25 mm (1 in) welds along the seam with 25 mm
(1 in) gaps between.
- Go back and complete the stitch weld to create a solid weld joint
with minimal heat distortion.
- 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.
- Prime with 2-part catalyzed primer.
- Apply sealers and anti-corrosion materials as necessary.
- Install all related panels and components.