1992-1994 Ford Ranger and Explorer Front Frame Horn Replacement

Introduction

To avoid replacing the entire vehicle frame, Ford Parts and Service Operations has made available front frame horn replacement sections for both the left and right sides. Included with the service part are templates for both inner and outer portions of the frame rail that identify where the cut lines are to be located. Refer to Photograph 1. All photographs contained in this bulletin are referring to the left side of the vehicle.

The replacement frame horn sections are manufactured with an insert to assist in fit-up and serve as a backer during welding operations. Prior to beginning this procedure, the vehicle frame must be returned to its proper dimensions through appropriate pulling methods.

Depending on vehicle engine, equipment and location of damage, there are certain mechanical components that must be removed to gain the necessary access required for cutting and welding. Regardless of which frame horn is being replaced, both front sway bar brackets must be removed so that the sway bar can be lowered and moved out of the way.

The 1-A crossmember, (located in the vicinity of the radiator support) is both bolted and welded to the vehicle frame. Refer to Photograph 2.

With the sway bar brackets removed, cut away the welds that secure the crossmember to the damaged frame horn. Replacement of the left frame horn necessitates complete removal of the steering gear box, as well as the serpentine accessory drive belt.

If the right frame horn is replaced, the engine air intake inlet (if equipped with the 4-cylinder engine) must be removed to gain proper access. Vehicles equipped with air conditioning and/or the V-6 engine may also have lines or hoses that may require removal to gain access.

When replacing either the left or right side frame horn, remove the stacking pin that protrudes from the bottom of the existing frame, just rearward of the cut line. This is necessary to achieve proper fit-up of the sleeved replacement horn, and can be accomplished by cutting the head off the pin with a reciprocating saw. The stacking pin does not have to be replaced.

The welding specification developed for this particular repair must be followed precisely to ensure proper weld penetration and subsequent joint strength.

The vehicle frame is coated with a hot melt wax when manufactured, and it must be removed from the area where the section joint will be made prior to fit-up and welding. This coating can easily be removed with wax and grease removing solvent.

Proper corrosion protection can be restored by standard refinishing methods, followed by the application of the same type of waxlike, creeping corrosion protection material normally used in unibody repair.

1992 For Ranger/Explorer Front Frame Repair Sequence

1. Locate the appropriate templates and verify they are the correct model, year and side. The templates are labeled Right Hand Inner Siderail, Left Hand Inner Siderail, Right Hand Outer Siderail, Left Hand Outer Siderail. Each template has arrows pointing in the direction of the front and top of the vehicle and will require trimming before use.

   The left hand side templates can be held in place by inserting the steering gear bolts through the labeled holes on the template and then through the bolt holes in the frame. After each template is in position, scribe a line on the damaged frame on both the inside and outside. Then connect these scribe lines on the top and bottom sides. Refer to Photograph 3.

   

   The right hand side templates also have locations marked where bolts should be inserted. After the templates have been secured to the frame, the cut out portions should be in alignment with the corresponding holes in the frame. A line can then be scribed on the damaged frame.

2. Do not cut directly along the scribed line when removing the damaged frame horn. Leave enough material on the front side of the scribed line to allow the edge to be ground back exactly to the line. This is necessary to insure a precise fit-up between the frame and the replacement part. Use a reciprocating saw or cutoff wheel for best results. Refer to Photograph 4.
   

3. Carefully grind a 30° taper along the edge of the replacement horn at the repair joint. Grind a 30° taper along the edge of the existing frame at the repair joint.

4. Use a wax and grease removing solvent to remove the hot melt wax coating from both the outside and inside surface of the existing frame, within approximately 2 inches (51 mm) of the repair joint.

5. Remove the primer from the outside of the replacement front horn, within approximately 2 inches (51 mm) of the repair joint. Also remove as much primer as possible from the inside of the box section and insert of the replacement part, within approximately 2 inches (51 mm) of the repair joint. This will help welding and minimize weld contamination.

6. On the vehicle frame at the cut line, cut or grind approximately a 1/4 inch x 1/4 inch (6 mm x 6 mm) notch at each of the four corners. These cut outs will enable tack welding to the insert when the replacement frame horn/backer are properly positioned. Refer to Photograph 5.
   

7. Remove any foreign material from both the existing frame and replacement part within approximately 1 inch (25 mm) of the repair joint (i.e. weld spatter and cutting burrs) to allow for easy and proper fit-up during assembly.

8. Install the replacement horn into the existing frame opening. Position the horn in its proper location and clamp securely in place, verifying all measurements including a consistent 5/32 inch (4 mm) at base of root gap. Refer to Figure 1.
   

9. Carefully review all aspects of the welding procedure. All specifications must be met before any welding is started.

   Using the included WELDING PROCEDURE SPECIFICATION, select the filler material, shielding gas, and welder settings to be used in welding the joint. Slight weaving from one side of the joint to the other may be necessary for complete penetration of the filler metal into both base metal sections and the insert material, as well as completely filling the root gap.

10. Be sure the repair joint and the immediate surrounding area has attained a temperature of at least 50° F before tack welding all four corners at the notched areas.

11. Re-verify all measurements after tack welding. Following the prescribed welding procedures, weld the upper and lower horizontal joints from corner to corner. Next weld the vertical joints from corner to corner. At the time of reassembly, the 1-A crossmember must also be welded to the replacement frame horn.

12. After all welding has been completed, grind the weld material so that it is flush with the siderails. Care must be taken not to thin the base materials. Refer to Photograph 6.
    

13. Use a dye penetrant to determine if any cracks or large voids exist in the weld joint after the welding process has been completed. If your establishment does not carry a crack detection penetrant in stock, the following products, made by Magnaflux Corporation, can be utilized. The shelf life of these products is approximately two years.
    • Spot Check Penetrant* SKL-SP
    • Developer SKD-NF/ZP-9B

      * These products can usually be found at welding supply shops. If not, please call Magnaflux Corporation at 708-867-8000 who will give you the locations of dealers in your area.

    If cracks or other defects exist, grind out the defects and repeat steps 9 - 13 until the area no longer shows any imperfections.

14. Clean the repaired areas and any exposed bare metal prior to priming and painting. The enclosed portion of the section joint should also be primed using a wand.

15. After refinishing, the repaired area and the replacement frame horn should be coated both inside and outside with an acceptable waxlike, creeping rust proofing material.

Welding Procedure Specifications

Due to the thickness of the frame rail, which is manufactured from mild steel, the accompanying welding information must be followed precisely to ensure proper penetration.

A M.I.G. welder capable of producing 200 AMPS at a 40% duty cycle must be used (i.e. Miller Matic 200).

Welding wire should be .035 diameter which meets or exceeds the American Welding Society Standard (AWS/ASME SFA5.18 E-70S-6) with a mixture of 75% argon and 25% carbon dioxide shielding gas. During welding there should be 1/2 inch (12 mm) or less wire sticking out of the contact tip.

With a 5/32 inch (4 mm) gap between the base metals, a continuous welding technique is used for all sides of the rail with full fill expected from one continuous weld pass. Cosmetic completion may be necessary.

Practice welds should be made on the discarded portion of the frame horn prior to welding the replacement part in position.

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.