About I-CAR - Current Events/News: e-newsletters: Advantage Online: February 26, 2008

Figure 1 - A replacement procedure for the front frame horn and a service part have
been available since the redesign of the Ford F-150 in 2004.

Figure 2 - The factory lap joint for the front section is just behind the third crossmember.

Figure 3 - The factory lap joint for the rear section is just ahead of the third crossmember from the rear.

FORD F-150 SERVICE FRAME SECTIONS AVAILABLE

Ford Motor Company has added two large front and rear frame section assemblies for repair options on the F-150 and Lincoln Mark LT light-duty pickups. The frame section service parts fit on F-150 pickups back to the frame redesign in 2004. The frame was again redesigned for the 2009 model year. The Lincoln Mark LT was introduced in 2006. All that was available before these additions was a right or left front frame horn replacement kit, removed and installed at a factory seam (see Figure 1). The new front frame replacement section includes the entire front third of the frame and the three front crossmembers. The new rear frame replacement section includes the entire rear third of the frame, the three rear crossmembers, and the spare tire hoist carrier assembly. The procedures for each frame section procedure accompany the replacement frame section parts.

The front and rear sections of the frame are attached to the center frame section with factory lap weld joints. When replacing the sections, the front replacement section is sleeved over the center section (see Figure 2), while the rear replacement section is sleeved into the center section (see Figure 3). The lap welds are made completely around the joints.

The front and rear frame sections are not available for all F-150 and Mark LT frames. The front frame section is not available for frames with a gross vehicle weight rating (GVWR) over 3,266 kg (7,200 lb) or for trucks with a manual transmission. The rear frame section is also not available for frames with a gross vehicle weight rating (GVWR) over 3,266 kg (7,200 lb). Although characters of the VIN help identify these features, the best way to determine if the truck is under the maximum GVWR is by decoding the VIN with the help of a dealership. If the frame service kits are used on the wrong frame the collision energy management of the vehicle could be affected.

There are some frame service parts required for each replacement procedure that are not included with the replacement part. Which parts are required depends on the model year of the truck.

Both of these frame replacement sections may be welded using the GMA (MIG) welding process or the stick welding (SMAW) process.

For GMA (MIG) welding, the machine must be capable of producing at least 150 amps. Ford recommends a single pass on the 360° lap joint, pushing the gun when welding in the horizontal position and pulling the gun going “vertical down” on the vertical welds.

For the stick welding process, the machine must be capable of producing at least 110 amps. The specified stick electrode is E-6011. Ford also recommends a single pass with this process, and pulling the electrode in both the horizontal and vertical positions, welding “vertical up” on the vertical welds.

The procedure for the front frame kit starts with disassembly of some of the sheet metal parts. Three-dimensional measurements are taken to determine if the frame requires straightening and alignment. Disassembly continues, including the complete removal of the front suspension and steering system and the front drive axle assembly and halfshafts. The engine/transmission assembly is raised and supported and the transmission support crossmember is unbolted and removed. The radiator core support is raised slightly above the body mounts. Any remaining wiring, lines, and related fittings from the frame section are disconnected and removed.

The front section is sleeved over the center section. The original lap joint locations are ground, taking care to not grind into the center section. The ground area of the joints are separated and the existing damaged front section of the frame is removed.

The replacement front frame section is slid over the existing frame ends. The section is supported and loosely clamped while three-dimensional measurements are taken to verify the correct position. After test welding on the original damaged section, tack welds are made to hold the frame section without the clamps and final measurements are taken. The final welds are made completely around the lap joint. Anti-corrosion coating PM-24 is applied to the inside of the repair area and Motorcraft PM-25 undercoating is applied to the outside of the area before final reassembly (see New Ford Corrosion Protection Recommendations in the January 15th, 2008 issue).

Disassembly for the rear frame section procedure includes removal of the pickup box, the spare tire hoist carrier assembly, and the fuel and exhaust systems. The vehicle is anchored, three-dimensional measurements are taken, and the frame is straightened as necessary. There are steps for securing the rear axle and spring assembly during the replacement procedure. There are also steps for using the frame rack towers to hold the cab and center section during the procedure.

The rear service frame section is sleeved into the existing center section near the forward leaf spring eye brackets. The existing GMA (MIG) lap welds that hold the spring eye brackets to the frame rail are ground off and the brackets are removed. The welds holding the forward and rear frame sections together are ground off. This allows removal of the complete damaged rear section. The service rear frame section is inserted into the existing center section frame rails and loosely clamped. Three-dimensional measurements are taken. After making test welds using the original damaged rear frame section, tack welds are made and final measurements are taken. Final welds are made completely around the overlap joint. The front axle brackets are installed, measurements taken, and the brackets are welded into place. Anti-corrosion coatings are applied, similar to the front frame section procedure, and the vehicle is reassembled.

Ford Motor Company has added two major service parts for repairs to the 2004–2008 F-150 and 2006 and newer Mark LT. In addition to the front frame stub, there are front and rear frame sections. All of the service parts for the frame are removed and replaced at factory seams.

More information on the repair of the Ford F-150 can be found in the I-CAR Live Collision Repair Overview for the 2004 Ford F-150 (FRD01) training program.

For comments or suggestions on the Advantage Online, please contact I-CAR Senior Instructional Designer Bob Jansen at bob.jansen@i-car.com.

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