May I ask how to tell if foot valve is Bad? Mine seems to make a big whine sound than a big whoooosh when I let off. And it use my air up fast.
First question: How often do you drain your air tanks? Water takes up space in the tanks, leaving you with less air volume which means reservoir pressure drops faster. Park the truck with the engine off on level ground and air system charged on level ground. Chock the wheels and have someone release the park brakes and hold the foot treadle to the floor. Check around the treadle valve for air leaks. Any leaking air out of the exhaust port with the pedal on the floor means the valve is no good.
Doing this I do not lose pressure and pedal does not sink to floor. But app gauge goes to just under 100 psi. As soon as I let off pedal it loses more air than it should. 3 pumps and warning light comes on. Air compressor seems on way out, takes a few secs for it to blow my thumb off the exhaust port. Trailer seems not enough pressure is going to it. It is a old 2006 utility. Is there any valve on trailer to look at? Secondary tank loses air faster than primary when pumped.
Can of worms Mr Gearjammer79 I have a couple of ideas. First off check all of your rubber dividers inside the two chambers that divide the service side from the spring side. If there is any rot inside them due to not draining your tanks at night the air will go right through and you will discover you aint got brakes worth a ####, when you process that problem, you will learn your sec is gone and pri is falling fast. And where you are in traffic is about to lock up 4 interstates on that particular exchange at the most exquisite SNARL of the rush hour get to work crowd that fixing to happen. That scenario was a real life incident with my mack milk truck. As it turned out all the rubber dividers were holey and the tanks never drained. That got fixed right quick once 10 gallons of sludge spit out of there by morning.
Failing Diaphragm inside brake chambers themselves. ~~~~~School Bus Mechanic: January 2006 Hissing brake chamber Today's brake diaphragms are petty permanent. As long you have a good air dryer you are sitting pretty.