DIY Network

Performance Add-Ons: Ground-Effects Kit, Part 2 From "Weekend Mechanic" episode WKM-307

Host Bruce Bonebrake and automotive specialist Rusty Fox thoroughly test-fit the fiberglass bumper-covers and side skirts on this Acura before sending the parts out to be professionally painted.

In this segment of DIY's Weekend Mechanic, host Bruce Bonebrake continues work on the ground-effects kit for the Acura with the test-fitting of the new body parts.

Materials:

In addition to standard auto-mechanic's tools (wrenches, ratchets, extenders, screwdrivers, nut-drivers, torque wrench, etc.), some of the specialty tools and materials used in this episode include a fiberglass ground effects kit, cold-air intake system with air filter and carbon-fiber laminate hood. An air-compressor and set of pneumatic tools (including a grinding wheel) is optional, but will be helpful for this project.

DIY Difficulty Rating for the Repair: This job is relatively straightforward, and requires little in the way of specialty tools. It should be easily within reach for most automotive do-it-yourselfers. We gave it a difficulty rating of 2 on a 5-point intermediate-level scale.

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Figure A

Ground-Effects Body Kit: Test-Fitting the New Parts

• With the factory body-parts removed from the vehicle, test-fitting of the new add-on parts can begin. This step is critical as minor adjustments and sanding may be needed to get a perfect fit. You'll also need to mark the locations for custom-drilling the holes for the screws that secure the parts to the car, as fiberglass add-on parts typically don't come pre-drilled.

• We began test-fitting with the front bumper guard.

• Carefully position the new fiberglass front-bumper cover onto the vehicle for a test-fitting (figure A).
  

  	Figure B
  	Figure C

• Check seams and locations where the new bumper-cover meets the body of the vehicle (figure B) to ensure a good fit. Check around the headlights and where the bumper will meet the closed hood. Note any locations where the fit is not exact, as sanding and adjustments may need to take place.

• Take the bumper-cover back off the vehicle. Where the fit is not exact, you may need to do some sanding to the edges of the fiberglass (figure C). For sanding fiberglass panels, use a fine-grit sandpaper such as 100-grit.

• It's best to sand in small increments, first sanding just a small amount and then re-fitting the body-panel on the vehicle. Repeat the process until you achieve the fit you want.

  Tip: When custom fitting new fiberglass parts onto the vehicle, don't make the fit too tight. The fiberglass will need a little room to expand once it's installed. Without any expansion room, the new parts could crack.
  

  	Figure D
  	Figure E

• Since our front bumper does not come pre-drilled, we mark and drill the locations for the plastic bumper plugs that held the original bumper cover along the front edge (figure D).

  Important: When drilling fiberglass, avoid drilling too close to the edge as this could cause cracking or splitting.

• The holes you drill in the new bumper-cover should be the exact same size as the original holes, so be sure to check and use the right size drill-bit. As long as the holes are drilled properly, the plugs should snap in place as they were before (figure E) and fit tight. If the plugs are worn or damaged, and don't hold the bumper-cover tightly in place, you should replace them with new ones.
  

• Next, move on to secure the sides of the front-bumper cover. Drill the hole for the side-screw (figure F) so that it's just slightly larger than the screw itself. This will ensure that the screw does not wear down the screw-hole as the body panel moves and flexes when the car is driven.

• Once the hole has been drilled, check for proper fit (figure G). Repeat on the other side, and secure with screws.

  Figure F

  Figure G

  
  

  	Figure H
  	Figure I

• With the front bumper installed, you can move on to the side skirts. Position the side-skirt and check for proper fit (figure H).

• Once the fit was checked out, we secured drilled and secured our side-skirts with two screws beneath the door opening (figure I). The holes drilled for the screws in the rocker-panel pieces must go through the fiberglass and into car's rocker panel. Use flat-head screws to secure the part to the rocker panel.

  Note: Additional screws are added at the wheel-wells later in the process, after the parts have been painted.

  Note: Some rocker panels are held in place by adhesive tape or glue rather than screws.
  

• Next, move on to the rear bumper. In our case, the rear bumper did have holes pre-drilled for installing onto the vehicle, but we still need to do a test fit. As with the front bumper cover, carefully lift the new panel into position (figure J).

• As you did with the front bumper, check seams and locations where the new bumper-cover meets the body of the vehicle to ensure a good fit. Note any locations where the fit is not exact, as sanding and adjustments may need to take place. In our case, there was a problem spot at the rear of the side-body where the curvature of the fiberglass piece didn't match the body (figure K). Trying to force this fit could cause the fiberglass to split.

  Figure J

  Figure K

  
  

• In a situation like this, some serious sanding is required. Since a substantial alteration was required to achieve the desired fit, we opted for using a pneumatic wheel with an 80-grit sanding pad (figures L and M). This made the work go much faster, and made it easier to grind a straight edge along the top of the body panel.

  Safety Alert: Always wear eye protection and a ventilator mask when using power tools to sand fiberglass.

  Figure L

  Figure M

  
  

• As with hand-sanding, sand just a little at a time and test fit the piece again. Repeat until you have the fit you desire (figure N). Remember, you can always sand a little more but, once you've sanded away fiberglass, you can't put it back.

• With careful sanding, we were able to get a good fit on the Acura (figure O). With the pre-drilled bumper cover, it was not necessary to insert the fasteners when test-fitting the bumper cover.

  Figure N

  Figure O

  
  

Important: Included in this segment are the steps in this automotive procedure as shown in the episode. These steps are general guidelines that are applicable to most vehicles. With any particular vehicle, there may be procedures, specifications, settings, tolerances, components, etc. that are specific to that vehicle. There are also variations according to the type and brand of repair-kit you select. Always consult your vehicle's service manual when undertaking significant automotive repairs, and read and follow the manufacturer's directions and precautions that come with your kit or replacement parts.

Safety Alert: Always wear eye protection and ear protection, and follow proper safety precautions, when working with power tools and pneumatic tools. Also wear eye protection any time that you are working beneath a vehicle.

RESOURCES :

The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books

Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896

Sport Compact Bolt-On Performance Guide: Import Cars (Sport Compact Bolt-On Performance Guides)
Author: Joe Pettitt
Order this book from Amazon.com.
Voyageur Press (October 2000)
ISBN: 1884089526