Well, I thought I should add my thoughts on the PRBX upgrade I just completed on the coach.
To recap, I felt my original Pacbrake was not performing as it should, so I started testing it. First, I just made sure it was being activated and closing as, and when, it should. I had my brother-in-law lay on the bed while I drove the coach, and he confirmed it seemed to be functioning properly.
The next step was to measure the back-pressure produced on long grades. I installed a gauge in the driverís area where I could see it, and ran a line back to the Pacbrake which connected to the test port on the side of the brake casting. I am in Colorado, so we went camping up in the mountains for 4 days, driving some of the typical steep (6-8%) grades.
The maximum back-pressure I ever experienced was 18 PSI, at about 2500 RPM. When the RPM dropped, so did the back-pressure and I mean dropped quick.
I immediately ordered the PRXB, and installed it. I am now in the Black Hills, in South Dakota, and have tested the new brake during the trip. Now, there have only be a few short grades on this trip, but steep grades were not needed for me to see and immediate improvement with the PRXB. I could tell the first time it activated. This thing works great! My back-pressure shoots up to 60 PSI as soon as the brake is energized, and stays there all the way down to 15 MPH, or about 1200 RPM (then the brake cuts out). Now, I will say that it doesnít do much above 55 MPH or so, but it is just as good as the original Pacbrake, (and better than my defective one), at those speeds. But drop down through the gears starting at 4th, and wow, this thing pulls you down.
I havenít had to touch my brakes once because of runaway speeds on this trip.
Oh yes, the swap-out from the old to the new PRXB took about 45 minutes. Very easy on my coach. This has been one of the best value upgrades I have done so far.
Very happy Pacbrake customer.