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PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange

PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
PacBrake C40301 PRXB Exhaust Brake for 2002+ Cummins 5.9L ISB – 3.5" Full Marmon Turbo Flange
: C40301
In Stock(10)
$895.00
$1,126.95

PacBrake Special


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Sale ends 03/31/2026 at 11:59:59
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PacBrake C40301 PRXB Pressure Regulated Exhaust Brake for 2002+ Cummins 5.9L ISB Engines with 3.5" Full Marmon Turbo Flange


PacBrake’s flagship product, the PRXB (pressure regulated exhaust brake), is the unquestioned leader in the supplemental brake industry. The patented PRXB design delivers the strongest braking horsepower, greatest speed reductions and shortest stopping distances possible without the use of service brakes. It maintains optimum retarding performance by maximizing the exhaust backpressure throughout the entire RPM range. Unlike a typical exhaust brake, which requires high RPMs to work properly, the PRXB delivers constant exhaust pressure (braking) as early as 1200 RPM through to the maximum allowable RPM. 

Controlled by a master ON/OFF switch, you can choose when to engage the exhaust brake with just the lift of your foot from the throttle pedal. PacBrake’s exhaust brakes provide whisper quiet supplemental braking that allows service brakes to be used much less, ultimately saving you money. They have the ability to be left on all the time, making it ideal for in-city driving or for steep, downhill grades. This product pays for itself as less wear on the brake pads means fewer brake jobs.

Product Benefits:

  • Provides 50 percent More Braking Power at Lower RPM's. PRXB gives you the best hold-back in the 1400-1800 RPM range (where you typically drive).
  • The spring controlled pressure regulated mechanism on the exhaust brakes protects against engine over-pressure.
  • When the brake is deactivated, exhaust flow is unrestricted and won't interfere with power output.
  • Patented 90 degree Non-contacting Butterfly Valve is specially engineered to maximize back-pressure while preventing seizing.
  • The brakes use industry exclusive Arcor nitride coating on housing and components which increases resistance to wear and corrosion while strengthening the exhaust brake and adding lubricity.

Applications:

  • Freightliner Cargo with Cummins ISB with EGR up to 230HP Rating - Engines Built After October 2002
  • Kenworth T300 with Cummins ISB with EGR up to 230HP Rating - Engines Built After October 2002
  • Sterling Cargo with Cummins ISB with EGR up to 230HP Rating - Engines Built After October 2002

Special Notes:

  • Direct Mount - Mounts to Back of Turbocharger

Other Information:

  • Delivers the strongest braking horsepower, greatest speed reductions, and shortest stopping distances possible without the use of service brakes
  • Maintains optimum retarding performance by maximizing the exhaust backpressure throughout the entire operating RPM range
  • Delivers maximum exhaust pressure (braking) as low as 1200 RPM through to the maximum allowable engine RPM
  • Provides increased performance and peace of mind with technology that protects the engine from the potential of overpressure
  • Withstands extremely high exhaust temperatures
  • Compliant with latest emission regulations
  • Severe duty and military approved
  • No risk of engine overpressure




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 The state of California requires that this warning be posted for people purchasing products that reside in California.

WARNING: Products may contain one or more chemicals known in the State of California to cause cancer and/or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov

Our particuler ISB Cummins is in a Freightliner Custom Chassis / 2000 Winnbago Journey. It currently has a Jacobs system installed, and the actuating cylinder has failed. Due to the age of the Jacobs part, very few replacements are available. Would this be a suitable alternative to "upgrade" the existing Jacobs component? Would we be able to use the existing 12V solenoid & toggle switches used to engage air supply to the current Jacobs unit?

Thank you in advance for your help with this.

-John Gladu
Owner, River Road RV Repair
Orrington, ME
( John Gladu Jr, 01/09/2019 )
I recommend a call to PacBrake direct for guidance on this. Their phone number is 800-663-0096.

I need to replace the PacBrake exhaust brake unit on my 2001 Holiday Rambler with 300 ISB Cummins w/Allison 6 speed. It has a inline clamped type w/ 3" exhaust. It to corroded to read numbers. Will this part fit? (C40301)

( Mark Taylor, 06/20/2015 )

Mark,

Unfortunately that application is a bit uncommon so there is no PRXB upgrade available for it. You would require part # C10900 as a replacement brake. If you would like to discuss further or place the order just give us a call at 360-736-2158. Thanks!

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