195 Chapter 9 Nonstructural Panel Repair Copyright Goodheart-Willcox Co., Inc. 3. Raising—As the arrowheads are pulled out, weld additional pins in any remaining low areas. Raise these areas gradually, starting with the lowest pin and ending with the highest. Pull each pin slightly in an effort to gradually restore the crown in the panel. Remove the pins and check the damaged area for level. 4. Leveling—Any remaining high areas should be lowered by tapping. Tapping on high areas without supporting adjacent low or properly contoured areas may cause the crown to collapse. Weld draw pins in place to support adjacent low or properly contoured areas. While holding a draw pin to support the panel, tap any high areas with a dinging hammer. 5. Shrinking—Any metal that was pulled too high by a draw pin can be lowered by shrinking with the draw pin welder. Heat the area with the welding tip, tap the heated area twice, and then cool the area with a wet rag. Figure 9–48 shows a tailgate with multiple body lines and reverse crown. The damage includes collapsed body lines and an arrowhead. These are the steps to follow when repairing body line and arrowhead damage using a draw pin welder: 1. Raising—Weld the tip of the slide hammer to the lowest part of the most-damaged body line. Raise it slightly by slide hammering. Disconnect the tip and weld to the next-lowest body line and raise it slightly. Continue welding, raising, and detaching, working all the damaged body lines in small incre- ments until the tip of the arrowhead begins to move. 2. Leveling—Weld just below the tip of the arrow- head. Slide the weight up on the slide hammer for one or two taps, and then pull on the slide hammer to put tension on the arrowhead. Tap the ridges of the arrowhead with a dinging hammer. Hammer from the outermost parts of the arrowhead toward the point. 3. Raising—Attach to the lowest body line and pull to put tension on the panel. Use a chisel hammer to restore the shape of the body line. Continue welding, pulling, tapping, and detaching on the remaining low body lines. 4. Shrinking—Any metal raised too high can be lowered by heat shrinking. To shrink by heating, weld the tip to the high spot, twist it free, and tap around the heated area with a dinging hammer. Cool the hot spot with a wet rag. Two-Sided Repair, No Body Line A two-sided arrowhead repair that does not involve a body line is relatively simple. The high-crown panel is stiff enough to be metal finished, but it may also be roughed out and filled. If a change in panel length is present, begin with step 1 below. If the panel length is correct, begin with step 2. The steps in performing this type of repair are as follows: 1. Pushing—Use a four-ton hydraulic power set to restore the length of the panel. As the panel lengthens, the lift reaction will raise the low area. 2. Raising—Use a dolly with the same contour as the underside of the undamaged panel to hit just under the point of each arrowhead. Start with the deepest arrowhead and gradually raise each. Continue tapping with the dolly until each arrowhead is raised. 3. Leveling—Hold the dolly tightly against the area under the point. Use a dinging hammer to lower the high ridges on the side of each arrowhead. Start at the bottom of the arrowhead and work toward the point. Alternate sides when hammering toward the point. The leveling releases the arrowhead. 4. Stretching—If the arrowhead has a sharp point that was not removed by hammer-off-dolly tapping, use hammer-on-dolly technique to stretch the upset metal. Press a dolly with the same contour as the underside of the undamaged panel against the inside of the panel, under the point of the arrow- head. Tap on the point with a stretching hammer. Start with light taps. If the metal does not stretch, tap harder. Use the dolly to raise the low areas that remain once the arrowheads have been released. Tap out on the underside of the panel with the dolly. If an upset area—a V-shaped groove in the shaft—remains, it can be removed by hammer-on- dolly stretching. Start hammering on the dolly at one end of the V-groove and work toward the other end. See Figure 9-49. 5. Picking and filing—File across the damage. Any shiny spots indicate high areas. Tap the high areas Goodheart-Willcox Publisher Figure 9-48. The tailgate is strong because of the many body lines. The damage makes it stronger.