Ford Taurus Front Rail Sectioning,
Rear Portion

Introduction

This bulletin will provide a step-by-step procedure for sectioning the lower left front unirail on 1996 - 2000 Ford Taurus/Mercury Sable vehicles. This procedure can provide significant savings over replacing the entire rail assembly when structural damage is confined to the rail in front of the firewall.

On this particular vehicle, collision damage resulted in a crushed impact bar and unirail end.

The inner and outer rail, including the internal reinforcement where it meets the rear outer reinforcement, were also distorted by the impact forces.

Procedural Notes

Prior to beginning this procedure, the unibody structure should be checked for proper structural alignment. Any variances that exceed OEM tolerances must be corrected before cutting or removing any primary structural member.

Proper welding equipment and procedures must be utilized to ensure sufficient weld penetration and strength. Practice welds should be made on a discarded portion of the damaged rail and tested for adequate weld penetration prior to welding the replacement section into position.

The engine cradle and powertrain will need to be removed prior to sectioning the damaged portion of the unirail. Removing the powertrain will allow easier access to the repair area for cutting, welding and refinishing operations.

Repair Sequence

1. This sectioning repair features a butt weld to attach the replacement rail to the existing vehicle structure at the section joint location. The outer rear side member from the kick up/firewall area is welded to the upper and lower flange joint near the section joint. The replacement unirail section is welded in place using an extension of the outer rail where it joins the inner rail at the cut-line as a natural weld backer. MIG plug welds at the factory spot weld locations will complete the repair.



2. Mark a vertical cut-line on the inner rail 145 mm (5 23/32 inches) rearward from the second access hole.



Using a cut off wheel, cut the inner rail along the cut-line. Be careful not to cut into the outer rear side member. It is necessary to cut slightly into the strut tower at the upper flange joint area to remove the damaged rail section.



3. On the damaged unirail, drill out the spot welds joining the strut tower and lower front apron to the top rail flange. Locate and drill the spot welds joining the rail to the outer rear side member forward of the cut-line. Drill from the outside to form holes for plug welds. Then, drill out the three existing spot welds on the inner portion of the rail, rearward of the cut-line. Be careful to only drill through the first layer and not into the underlying reinforcement.





4. On the replacement rail, remove the factory spot welds that secure the strut tower and lower front apron to the rail. Do not drill into the rail. Locate and scribe a vertical cut-line on the inner portion of the rail, 142 mm (5 19/32 inches) rearward from the second access hole. The difference in cut-line dimensions between steps #2 and #4 will provide a 3mm root gap for welding.



Drill out the three spot welds on the inner portion of the rail rearward of the cut-line. At the cut-line, use a cut off wheel to cut the inner rail. Be careful not to cut into the outer rail extension located behind the cut-line.





5. Fit-up the replacement rail section and clamp in place. Re-check all measurements to verify that the replacement rail section is in the proper position. Locate the plug weld holes in the upper and lower flange areas of the outer rear side member where the three layers of metal are joined. Scribe these locations on the replacement rail. Remove the replacement rail from the vehicle and center punch the marked holes.



6. Use a hole saw or equivalent to drill 8 mm (5/16 inch) diameter plug weld holes at the marked locations. Drill 10 mm (3/8 inch) diameter plug weld holes at the corresponding locations in the outer rear side member.



7. Remove grease, dirt and any rustproof coatings from all surfaces of the vehicle unirail at the section joint and plug weld locations. Also, carefully remove any e-coat, primer, paint or cutting burrs from the existing frame and the replacement part at the weld joint and plug weld areas as well. Do not removing any pre-existing galvanized coatings or thin the base metal. Apply weld-through primer as necessary.



8. Install the replacement unirail section into the existing structure. Clamp the replacement section securely in place.



9. Re-check all measurements to verify that the replacement unirail section is properly positioned. Weld the horizontal joint in 19 mm to 25 mm (3/4 to 1 inch) increments while alternating weld locations to minimize heat build-up. Plug weld the inner and outer surfaces in all of the factory spot weld locations.



10. After all welding is complete, grind the weld material so that it is flush with the original rail surface. Be careful not to grind into the base materials.



11. Restore the original corrosion protection by re-coating the repaired area and the replacement unirail section, both inside and outside, with the proper primer, base and top-coats. Complete corrosion protection recommendations can be found in Tech-Cor Automobile Research Bulletin 1986-7, Restoring Corrosion Protection During Vehicle Repair.

The information provided in this bulletin is for educational purposes only. Although every effort has been made to ensure the accuracy of the information contained in this bulletin, Tech-Cor assumes no responsibility or liability for any repairs performed using information from any publication issued by Tech-Cor.

Any person performing repairs must determine whether any suggested or recommended procedures or repairs are suitable or appropriate for the particular vehicle being repaired. The repairer remains solely responsible for such determination, as well as for the proper completion of the repairs.

Reproduction of this bulletin is not permitted without the written approval of Tech-Cor.