DIY Network

Frame Straightening and Repair Preparation Car frame and body repair gets underway. From "Trade School" episode DTRS-309

Instructor Mike Rohleder guides apprentice James Ackerman to further develop his skills by tearing down and later restoring the damaged front end of a sport utility vehicle.

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Note: Although the damage looks significant, modern front ends are actually designed and built with crumple zones to minimize the risk of passenger injury during a collision.

1. James first removes the damaged pieces such as the bumper, one fender, and the hood (figure A). While these damaged parts are eventually headed for the scrap pile, James keeps them standing by in case he can use some of their attached hardware.

2. He also takes careful inventory of the "good" parts that he removes, and then inspects for hidden damage. Because the radiator will later be removed, James drains the anit-freeze from the radiator and captures the AC coolant in a refrigerant containment system (figure B). He notes that the radiator support needs replacing, but leaves it in place for the time being.

3. James drives the vehicle onto a frame rack to investigate whether or not the frame was bent during the collision (figure C). A frame misaligned by mere millimeters can directly influence the performance of important safety features such as airbag deployment, seatbelt function, and crumple zones--so James knows this is a critical step in the repair.

Figure A

Figure B

Figure C

4. After setting a long electronic sensor beam directly under the vehicle, James hardwires it to a diagnostic computer, and then inputs the information for this particular make and model (figure D).

5. James attaches a series of probes at specific locations along the vehicle's frame (figure E). Once activated, each probe emits a signal spark, which the sensor beam reads to reference its position. The results reveal a slightly misaligned frame.

Figure D

Figure E

6. To straighten the frame, James first secures the vehicle to the rack with a clamping system (figure F). He then makes a series of connections to tightly wrap chains around the front of the frame (figure G). James feeds the chains up and over the racks hydraulic towers (figure H).

Figure F

Figure G

Figure H

7. With the vehicle locked down, and the chains pulled taut, James activates the hydraulic towers with a foot pump (figure I). Mike keeps watch on the computer as the rising towers deliver up to 3,000 pounds of pressure to slowly pull the frame slightly past its intended alignment. To return the frame to the proper alignment, James hammers on the frame to relax tiny molecules within the steel (figure J).

Figure I

Figure J

8. James takes advantage of the locked-down vehicle to bolt a hitch to the already damaged radiator support, hook on a chain, and then pull the vehicle's bowed sheet metal carcass back into alignment (figure K).

9. With the frame straightened, James drives the vehicle off the frame rack, and then detaches several engine components, including the radiator, to gain access to the damaged radiator support, which is the main structural component on the front end of every vehicle (figure L).

Figure K

Figure L

10. To remove the radiator support, he starts by grinding through the original factory spot welds (figure M). He follows up with an air hammer to cut the component out (figure N).

11. James cleans up the old spot welds using a disc grinder. With all the damaged parts removed, James is now ready to reassemble the front end (figure O).

Figure M

Figure N

Figure O

In the next segment, James' collision course concludes with a front-end restoration.

RESOURCES :

ABRA Auto Body and Glass
Website: www.abraauto.com