Ford Windstar Front Unirail Section Procedure

This Research Bulletin involves a sectioning procedure for the left front unirail on a 1996 Ford Windstar minivan. Although this bulletin focuses on the replacement of the driver side unirail, the same basic procedure applies to the passenger side as well.

The rail on this particular vehicle platform extends to a point behind the front seat mounting area, with the rear portion welded to both the toe pan and floor. This makes complete removal both difficult and time-consuming, as well as requiring extensive dismantling of the vehicle interior.

During left frontal impacts, a flange on the radiator support baffle can be pushed rearward, cutting into the wiring harness at this location. If wire damage is present, refer to Tech-Cor Information Bulletin 1995-4, Repairing Collision Damaged Wiring, for proper repair procedures.

Prior to removal of any structural components, the vehicle must be pulled and aligned to return the structure to its proper dimensions. The drivetrain assembly must also be removed to gain proper access for spot weld removal and subsequent plug welding operations. During disassembly operations, an additional inspection of the wiring harness should be made in the area immediately in front of the battery.

The "C" channel vertical cut-line is scribed 80mm forward (measuring toward the front of the rail) of the leading edge of the elongated hole located in the external reinforcement that surrounds the rail at the kick-up.

The replacement "C" channel vertical cut-line is scribed 83mm forward (measuring toward the front of the rail) of the leading edge of the elongated hole located in the external reinforcement the surrounds the rail at the kick-up.

After the replacement "C" channel has been cut, an additional piece of metal material measuring approximately 13mm (1/2 inch) in width is cut from the unused portion of the replacement rail. The backer is cut in two pieces and trimmed to fit inside the "C" channel.

The sleeve, or backer, is welded to the inside of the existing "C" channel so that approximately 6mm (1/4 inch) protrudes from the end of the rail.

The section joint uses an offset cut that incorporates a backer in the "C" channel, while the closure panel is installed with an overlap. This location was chosen to facilitate welding and refinishing operations, as well as allowing ease of application of corrosion protection materials. A square is used to ensure that the scribe lines on all three sides are in proper alignment. This procedure applies to both the damaged and replacement rail "C" channels.

Prior to welding the sleeve in place, the corners of the existing rail are notched to accommodate tack welding the backer in place before the replacement section is installed.

During fit-up, a 3mm (1/8 inch) root gap is maintained on all three sides of the "C" channel for proper weld penetration. Once the replacement "C" channel is tack welded, it may be necessary to notch out the rear portion of the elongated hole on the top of the "C" channel. A portion of this hole may have been covered by the sleeve insert and should be reopened to accommodate the brake line retaining clip. Prior to welding the "C" channel in place, the closure panel should be installed and clamped to verify proper dimensions and fit.

The cut-line is scribed on the damaged closure panel (measuring toward the rear of the vehicle), 100mm (3-15/16 inch) from the leading edge of a splash guard retaining clip hole that is stamped in the center of the closure panel.

The replacement closure panel uses a 5mm (1/4 inch) overlap in the area adjacent to the rail kick-up. The cut-line on the replacement closure panel is scribed 105mm (4-1/8 inch) from the existing retaining clip hole to allow for the 5mm (1/4 inch) overlap.

NOTE:
Verify that the splash guard hole in the damaged and replacement closure panels are in the same location.

The replacement "C" channel is stitch welded to the original rail.

The closure panel is plug welded to the "C" channel, while a stitch weld is made at the overlap joint.

Welding Information

Prior to any welding operations, the weld site must be cleaned to remove grease and dirt as well as primers and paint, without removing factory corrosion protective coatings or grinding into the base metal. Do not remove any pre-existing galvanized coatings. Do not use an oxyfuel (oxyacetylene) gas torch.

After cleaning, a weld-through coating must be applied to all bare metal in the overlap area of the weld sites. All welding should be performed with a M.I.G. welder (Metal Inert Gas, now called G.M.A.W. or Gas Metal Arc Welding).

Welding wire should be either 0.023/0.025 inch (0.6 mm) diameter which meets or exceeds the American Welding Society Standard (WAS-E-70S-6) with a mixture of 75% argon and 25% carbon dioxide shielding gas.

Do not concentrate all welding efforts on one area, but alternate sites so that each welded area has time to cool down before the welding is continued. All continuous welds must be made in 13 - 19 mm (1/2 - 3/4 inch) increments which helps to minimize heat build up which can cause metal strength loss and panel distortion. The welding equipment must also be properly adjusted by making and testing practice welds on similar materials.

Corrosion protection, including the refinishing of replacement components should be performed as outline in Tech-Cor 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.