another Pacbrake question - '07 5.9

[Dan Simmonds]

I recently purchased a prxb kit from Pacific Clutch & Brake & installed the kit on a bran-new '07 5. 9 yesterday. Installation was flawless - components are all high-quality.



I test drove the truck empty after the install - immediately noticed how *very* quiet the Pacbrake is (as compared to the mopar-jake). The sound of the Pacbrake air shut-off was actually louder than the brake operating itself.



Question: I have not hooked the new truck (under 50 miles on the ODO) to a loaded trailer yet to try out the Pacbrake properly. Does the braking performance of the Pacbrake increase with engine load (not RPM?) For instance, the Pacbrake, as installed now, has virtually no effect on slowing the empty truck, so I'm thinking there just needs to be a load (heavy downhill run) on the engine to really make the Pacbrake work?



On another sidenote, I was able to quickly locate an exhaust elbow leak due to an improper alignment of the Pacbrake elbow (my fault). The elbow joints are now tight with no leaks around the elbow.



Is there something else I should check for to expect more performance from the Pacbrake just running empty, or is it just designed to be soft-functioning with no load?



Thanks

 

[HBarlow]

I can't speak for a PacBrake since I haven't owned one but they function just like the two Jake brakes I've owned.



Higher rpms produce more exhaust braking.



Differential gearing and transmission gear selected will make a big difference. If your truck has standard 3. 73 gears you will notice less braking than an identical truck with 4. 10 gears. Lkewise, if you downshift you'll increase braking.

 

[Dan Simmonds]

Harvey, thanks, yes I realise higher RPM's increase the braking power, however in this case any RPM between 1000 and 2100 had the same result on the braking power. Maybe it's just the design of the Pacbrake I need to get used to.

 

[HCanales]

Try going 80mph and slow down with and without the pacbrake, you should notice and feel the difference. I'm not sure if I have a Pacbrake or Mopar Jake, I know that the controller knob says Cummins. I can't see either being any different.

 

[TAbbott]

AT higher rpm, the various exhaust brakes are fairly equivalent. The PacBrake claims to function better than the others at lower rpms because it maintains backpressure better at lower rpms.

 

[Dan Simmonds]

I think I just fixed my own problem... found an airleak in the air tank drain plug that wasn't letting the butterfly close all the way because of low air pressure!

 

[MoparDave]

Glad you found the leak, I was about to comment that your brake is not working correctly. You can tell when its working even without a load.

 

[Dan Simmonds]

Yes for sure - and I have to say the Pacbrake is very impressive in performance (now that I repaired the air leak). It's noticably more aggressive & faster-acting than the stock Jacobs in my 6. 7L truck.

 

[JCleary]

Yeah, it's a nice unit. I love mine. No vacuum pump to take out the belt either!

 

[Pacbrake]

Dan I'm glad to hear you got it figured out.

 

[SBeretz]

Yeah, my Pacbrake is awesome, it works really well. I have came out of I74S into NC from Va, and was able to keep my truck under the speed limit with my toyhauler behind me. I actually had to roll on the fuel to not slow too much. Empty, the brake runs until the trucks stops.

 

[Dan Simmonds]

Well, admittedly I probably had the most easy Pacbrake installation ever - I did it on a truck with less than 50 miles on it, so the exhaust clamp unbolting work was a piece of cake. It took me about 8 hours, but if I had it to do over again, it would easily take only half that (I'm slow & careful the first time through a new job). Yes it's a good feeling when your brake works so well you actually have to give it some fuel to keep the truck rolling.



Very pleased with the Pacbrake design.



Dan