I have about 30K on my PacBrake compressor. So far, I have not had many problems with it, but I HAVE had problems with the air hose connector leaking air from time to time. I properly torqued it and I believe that the overall engine vibrations are the culpret with regard to it loosening and leaking. I finally removed it from the compressor, ran a line with a shutoff valve in it to a remote location up front behind the bumper for easier access/use. The shutoff serves nicely to stopping any air loss that happens from a small leak which would result in a continuous operation of the compresssor, of course, shortening it's life considerably.
I got out my infrared heat temp gun and found that the operating temps were MUCH higher than 85*s wcjp has, sitting on top of the engine, more like 130-140*s, but that could be the difference in the Washington climate and the New Mexico climate in overall ambient operating temps. I also do not like the fact that the hood insulating materials makes a little contact with the compressor. That kind of defeats the rubber vibration dampening at the mounting points and could result in creating a solid mounting environment for the compressor, which is not good for it.
In any event, I think I am going to move the compressor somewhere else that would be a little cooler and that has less vibrations, that constant engine heat will surely shorten the compressor lifespan and the vibrations, well, yet to be determined as to what problems they could cause other than loosening connections.
Since more and more people are talking about compressor failures with much less mileage than I have on mine, I guess it's time to seek having a spare just in case I'm out somewhere towing and need the brake. I live in the mountains, the brake is a necessity for grades, I tow heavy, it also assists in towing needs. By the way, I never have turned it off, I run it loaded or unloaded, great for overall braking and save in the costs of brake pad replacements and rotor wear.
CD