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Part #: PBC40009

Pacbrake C40009 InLine Mount PRXB Exhaust Brake

1999-2003 Ford 7.3L Powerstroke (Manual)
Part #: PBC40009
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Pacbrakes 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, Pacbrakes 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.


In order to have consistent and effective braking over the entire RPM range, it is important (and necessary) to maintain constant backpressure. To achieve this, Pacbrakes patented design has incorporated an additional waste gate on the butterfly valve to regulate the amount of exhaust flow that is being passed through. The flow is controlled by a spring-loaded arm, whose pressure rating and location are key factors in the functionality of the PRXB. Located outside of the housing and away from the heat, the spring is able to maintain its strength and durability for years of proper and precise braking performance.

Backpressure is created by exhaust flow entering the housing, hitting the closed butterfly valve and being forced back out in the direction it came. It is maintained by the pressure-controlled spring that is located on the outside of the exhaust brake housing.

As the engines RPM increase, the spring compresses and the arm moves away from the butterfly valve, therefore releasing more exhaust flow through the orifice. As the RPMs decrease, the spring releases and the arm applies pressure back onto the plate, covering the hole, and ultimately releasing a smaller amount of exhaust flow.

There is less than a 10% change in backpressure over the entire RPM range on the PRXB

Features & Benefits:
  • PRXB Delivers Strongest Braking Horsepower
  • Less Wear & Tear On Service Brakes 
  • Ideal For In-City Driving Or Steep, Downhill Grades
Vehicles with aftermarket 4" O.D. exhaust systems will require C11400 adapter. (see below)


  • MFG. NumberC40009
  • Manufacturer NamePacbrake
  • Shipping Weight35.00 lb.


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Most Popular Questions

Does the PBC40009 come with all the parts air tank etc. ? 1999.5 Ford 7.3 Diesel Manual trans.
View Staff Answer 
I have a 2002 Ford f350 6speed how will this work for my rig what u recombine is there a kit? Recommendation
View Staff Answer 

The PACBRAKE C40009 INLINE MOUNT PRXB EXHAUST BRAKE is designed for all 1999-2003 Ford 7.3L Powerstroke vehicles with a manual transmission. The exhaust brake comes as a complete kit.
However, there is one more item we recommend purchasing which is the PACBRAKE C18041 SWITCH-PAC. This will mount the exhaust brake switch on the shifter for easy access.

Lastly, if you have a 4” aftermarket exhaust you will require the PACBRAKE C11400 4" MOUNTING GROUP.

i have a 2001 f 250 so what would lock the coverter up on my automatic
View Staff Answer 

The PACBRAKE C40009 INLINE MOUNT PRXB EXHAUST BRAKE is designed for a manual transmission truck.
If the 1999-2003 Ford 7.3L Powerstroke is an automatic you would want the PACBRAKE C40019 INLINE MOUNT PRXB EXHAUST BRAKE.