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How To's

3-Pc. Dyna-Flex 8” Chrome Exhaust Pipes Install

INSTALLATION OF 3-PIECE DYNA-FLEX 8” CHROME EXHAUST PIPES
  ON 379 UNI-BUILT PETE WITH ROD PICKETT LOWER ELBOWS AND CUSTOM-BUILT 8” STAINLESS ‘TEE’ PIPE.

Parts cost approximately $2,850. This includes:

     
  • Two 8” x 114 turnouts with pickett elbows  
  • Four 8” “wide” style Pete cab clamps  
  • Two chrome lower cab exhaust mounting brackets  
  • Eight rubber exhaust mounting grommets  
  • One 4 State special built 8” outlet and 5” inlet stainless exhaust tee  
  • Four 8” band clips  
  • Two 10” long pieces of 8” flex pipe  
  • One 5” band clamp  
  • Two 8” chrome support clamps to hold tee pipe to chassis

All parts available at www.4statetrucks.com

Typical installation time is 6 – 7 hours.
 

STEP 1:

     
  • Completely remove original exhaust system, including mufflers, stacks, elbow, flex pipe and exhaust “tee” pipe.  
  • It will also be necessary to remove the 5” diameter exhaust support clamp from the chassis and replace the lower portion of the clamp/strap assembly after step number 7.

STEP 2:

     
  • Remove the original lower cab exhaust brackets.  
  • Install the chrome replacement brackets and new rubber mounting grommets .

     

    STEP 3:
        If your upper cab exhaust bracket has a large “C” shaped muffler support bracket then you need to follow these steps:

     

  • Grind thru the rivets that attach it to the cab bracket
     

  • Discard the “C” shaped bracket
     

  • Cover the cab and glass areas on the cab during the grinding procedure so sparks do not get imbedded in the paint or glass.
     

  • CAUTION – Wear eye protection when using grinder and cut-off tools!
     

  • Install new rubber exhaust grommets directly into cab bracket.
     

     

    STEP 4:

     

  • Install custom tee pipe and loosely connect 5” connection.
     

  • Support tee pipe with wood blocks or jack stands temporarily.
     

     

    STEP 5:
     

     

  • See photo – the inlet end of the DYNA-FLEX elbow is reduced to 5” and intended to be used with 5” diameter tee pipe. We have chosen to remove the “reduced diameter” portion of the elbow using a die grinder and cutoff wheel. This should help with eliminating “back pressure”.
     

  • CAUTION – Wear eye protection when using grinder and cut off tools!
     

     

    STEP 6:
        We find the easiest method to install the three-piece type exhaust pipes is to fully insert the elbow into the spool assembly and then install the elbow and spool on the truck as one assembly. DYNA-FLEX supplies hi-temp silicone with all three- piece pipes. This will further eliminate potential exhaust leaks. We advise that you use the silicone on both spool connections.

     

     

     

    STEP 7:

     

  • Lift the spool and elbow assembly into position.
     

  • Attach the tee pipe with the short piece of the 8” flex pipe. This operation will require two people to minimize unnecessary scratching and blemishes.
     

  • Slightly spread open the lower 8” chrome mounting clamp and slide over the top end of the spool and slide it down the spool into correct position.
     

  • You can put a rag or masking tape around inside area of the chrome 8” clamp as you slide it down the spool to eliminate possible scratches to chrome exhaust.
     

  • Slide the upper 8” mounting clamp over the top end of the spool and loosely install all four bolts in cab brackets.
     

  • Check alignment on elbows, spools and tee pipe.
     

  • Tighten all connections.
     

     

    STEP 8:

     

  • Slide the upper stack section on to the spool section. Don’t forget to use silicone once you get the turnout positioned at the “angle” you like best.
     

  • Tighten clamp completely.
     

    STEP 9:

     

  • Do a visual inspection beginning at the “tee” pipe inlet and work your way up to the upper cab clamps.
     

  • Check each clamp connection.
     

  • Make sure all are bolts and clamps are tight and secure.
     

  • Start vehicle and check for exhaust leaks.
     

     

     

    STEP 10:
       
        Job done! Thanks goes to Dan Thompson for letting us photo his 99 Peterbilt “Independence” for this Special Installation How-To Feature.

     

    Note: If you remove the two original mufflers, D.O.T. will require you to install a muffler under the vehicle (Federal Law).