As far as relying on the over pressure safety valve when having the pressures greater than 150 lbs, if it were my truck, I would not operate it with those high pressures since the lines are old and plastic and could blow out on you. It might make a funny noise that your kiddies might like to hear(pressure relief valve operation), but will cost you more time and $ when you have to replace those lines in your truck and you might have to cage your brakes to get her home (not fun).
Bigwhale, thanks for the youtube tip, I did watch the video. I just got my truck, thinking it was very cool to have a monster, as well as give new life to tired soldiers, but to my dismay realizing these may require more mechanical aptitude and commitment than I can ever muster. My head is spinning from trying to read all the manuals online or even find the information. Every time I drive the truck (4 so far), there is some new nuance and I spend night after night trying to figure it out. I'm starting to wonder if I made a mistake, since the effort to build proficiency in operating and understanding these, at least for me, with my OCD, is Herculean. I never served and never drove these, so it makes things even worse... As far as the air blow noise, do I understand you correctly that my situation is not normal? Again, in my situation, the air pressure reaches some high level, and then gets blown off with attendant noise. I haven't tracked the exact PSI when it happens or how often, but guesstimate it's b/w 125-150 PSI. If I am just driving at 30 mph and not using brakes, every minute or so it makes that whooshing noise. I'm just trying to figure out if it's normal or not. I was thinking of taking it to a truck service center just to get some education and assistance, but I presume they are going to bend me over, realizing I have no clue. My truck is a RRAD 2011 overhaul, so I always assumed mechanically I will be in good shape. Now I am wincing every time I think about her.
