182 Section 2 Nonstructural Repairs Copyright Goodheart-Willcox Co., Inc. machine applies pulling force to straighten the quarter panel and trunk opening. A hook has been placed inside the trunk vent hole. Notice that the metal around the vent hole has torn from pulling on the hook. The area where the hookup is made must be stronger than the pull. If the metal is weaker than the pull, the metal will tear. Hooks should only be placed where the metal is strong, such as where there are two layers of metal or channels. Avoid holes in unreinforced single-thickness panels. Bolts, washers, and nuts placed in existing holes can also be used as attachments for pulling. The vehicle shown in Figure 9-15 was hit in the front and has folding damage on the fender. Lengthening the panel will correct the damage. The attachment is made by inserting an eyebolt through a hole in the panel. A washer and a nut are threaded onto the end of the eyebolt. The corrective force is acting only on the surface area of the washer. As with hooks, the attachment area may be damaged if the folded area resists movement. If the folds do not move, the metal around the attachment holes may stretch or tear. Another method of attachment is to weld a plate onto the damaged area. A piece of scrap sheet metal can be used, or specially made pull plates are available. Figure 9-16 shows welded pull plates and a puller. The plates are MIG welded to the damaged panel. Be careful when welding, as excessive heat can further damage the panel. The pull is concentrated at the welds. More welds spread out the force of the pull. The pull can be made with a slide hammer or a hydraulic ram. The pull must always be parallel to the welds and the plate. If the pull is not parallel to the welds and plate, the plate will twist and may break. There are two types of corrective force that may be used to pull an attachment: tension and shock force. Tension is a constant force that can be used to pull an attachment. A constant pull on a damaged panel will draw the damage in the direction of the pull. A frame machine with hydraulic rams or a come-along can supply a constant force. A shock force is not constant. Instead, it is applied as a series of blows. A slide hammer is used to apply Goodheart-Willcox Publisher Figure 9-14. This vehicle is mounted on a frame machine. Two clamps are set to remove the damage in the left quarter panel and rear body panel. Pulling on the hook ripped the metal and did not straighten the damage. Goodheart-Willcox Publisher Figure 9-15. The eyebolt is inserted through a fender bolt hole. It is held in place with washers and nuts on the front and back. It is being pulled with a hook and a ten-pound slide hammer. Goodheart-Willcox Publisher Figure 9-16. A pull plate is welded to the damaged portion of this panel. The damage can then be pulled out with a self-tightening clamp and a hydraulic ram or a slide hammer. Welded pull plate