DIY Network

Truck Upgrade: Cat-Back Exhaust From "Weekend Mechanic" episode WKM-310

	Bruce Bonebrake installs several upgrades to the GMC truck to enhance overall driving, safety and driver enjoyment.
	Figure A

In this episode, Weekend Mechanic host Bruce Bonebrake demonstrates the steps in several special upgrades on a 2002 GMC Sierra truck. A new exhaust system is installed, new tires and wheels are installed with wireless remote pressure/temperature sensors, and a rearview mirror with compass temperature readout is added. Finally, the existing radio is replaced with a new GPS CD/Radio.

In this first segment, the factory-standard single exhaust system is replaced with a new "cat-back" dual-exhaust system for enhanced engine performance and that deep "vroom!" that some auto enthusiasts crave. The new muffler has welded construction, dual outlets for two tailpipes and stainless-steel tailpipe tips.

Materials:

In addition to standard auto-mechanic's tools (wrenches, ratchets, extenders, screwdrivers, nut-drivers, torque wrench, etc.), some of the specialty tools that will be needed for the projects in this episode include air chuck, tire gauge and valve tool (figure A) wire-strippers and wire cutters, air wrench and safety glasses. An air-compressor and set of pneumatic tools will is optional, but may be very helpful for this project.

DIY Difficulty Rating for the Project: The projects featured in this episode are all fairly straightforward, and should be no problem for experienced automotive do-it-yourselfers. Overall, we gave the projects a difficulty rating of 2 on a 5-point intermediate-level scale. It took us about 12 hours to finish this job. Depending on the nature of your upgrades and type of vehicle, your work time could vary. Allow yourself a full weekend to complete these projects properly.

The basic steps are outlined below:

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	Figure B
	Figure C

Cat-Back Exhaust Upgrade

Removal of the factory exhaust on this truck is fairly simple. The muffler pipes simply need to be unbolted and the system disconnected from the three exhaust hangers. After that, the assembly should come out in one piece.

Safety Alert: As a standard safety precaution, don't rely solely on a jack to support the weight of a vehicle. When using a jack to access or work beneath a vehicle, always use jack stands for support. Make sure that the jack and stands that you use are rated for the weight and type of your vehicle.

• Begin by removing the nuts and unbolting the flanges where the two sections of the exhaust pipe connect near the engine (figure B). Separate the exhaust flanges slightly to make it easier to remove the exhaust system.

• Remove the exhaust system from the rubber hanging mount near the front of the muffler by sliding the rubber mount to one side (figure C). Repeat the process at the other two rubber mounts.

  Important: Use caution not to damage the rubber mounts. These may be fairly difficult to disconnect. Some parts may be reused on the new exhaust system.
  

• Once the hangers have all been disconnected, carefully lift out the factory exhaust system (figure D).

  The new exhaust is installed by building the system on the truck a piece at a time. First, connect the short pipe that will connect the exhaust flange to the new muffler. The exhaust is hung on the original exhaust bracket (figure E) and bolted in -- but not yet tightened fully.

  Figure D

  Figure E

  
  

• Next, install the new muffler onto the short pipe (figure F) using pipe clamps. Again, the piece should be bolted in, but not yet tightened.

  The pipe clamp at the rear of the muffler also serves as the hanging bracket (figure G). Slide it onto the rubber mount to hold the muffler secure at the back.

  Figure F

  Figure G

  
  

• Since this exhaust system has twin rear-pipes, install the first one and angle it up into position.

• Install the second pipe clamp (figure H) so that the other twin-pipe can be installed on the right side of the vehicle (figure I).

  Important: The exhaust pipes should hang without touching the frame or bed of the vehicle.

  Figure H

  Figure I

  
  

• The rear pipes use hanging brackets that came with the new exhaust system. Bolt these brackets onto the frame and use hanging clamps to secure the pipes, following the manufacturer's instructions. The clamps on the brackets serve both to hold up the pipes and secure them to the shorter end-pipes. Once again, bolt the clamps into position, but don't yet tighten completely.

• With the clamps in place, now you can install the end pipes and angle them so that they point straight toward the rear-end of the truck (figure J). Make certain that the are angled down slightly so that condensation can run out the ends.

• With the system installed, go back and tighten all the bolts and clamps securely.

• Finally, install the chrome-plated tops on the dual end-pipes, adjust them into position and tighten them down also (figure K).

  Figure J

  Figure K

  
  

  That completes the exhaust-system upgrade. The only thing left to do is take the truck down off the jack and jack-stands, fire up the engine and see how it sounds.

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. Also wear eye protection any time that you are working beneath a vehicle.

Safety Alert: As a standard safety precaution, always disconnect the vehicle's negative battery cable before you begin work on any electrical or mechanical components.

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