Re: Air Leak Down
Reply #38 –
Remember, if you make any modifications to the air system that involve the wet tank or the front and rear brake tanks, you are messing with the components that make your brakes work. I think (but don't know for a fact) that any fittings and plastic lines used should be meet DOT approved standards. Plastic line, especially, should be high quality, because the heat under the coach and around the rear axel and engine compartment can get pretty high. I learned this lesson when I first installed my air pressure gauge in our engine compartment. I ran cheap plastic tubing from the D2 regulator up to the gauge. On our first trip after the installation, the plastic line got so hot (from engine proximity) that it softened and pulled out of the compression fitting on the back of the gauge. This, in turn, caused the D2 to not register the pressure in the wet tank, so the engine air compressor did not know when to cut out. My first clue was when both our dash air pressure gauges pegged out at 150 psi. When I walked to the back of the coach, I could hear the 150 psi safety relief valve (LOUDLY) blowing off excess pressure in the wet tank. Luckily, I had used a small brass needle valve on the D2 port where I connected the plastic line. Closing the needle valve restored everything to proper operation. Once we got home, the cheap plastic line was replaced with a DOT rubber hose with braided stainless outer cover.
My long-winded way of saying "Always use high quality fittings and air lines on any air brake tank mods".