Pump Down.

all you're doing is checking your emergency and tractor protection valve. that they both pop out with low air pressure and wearing out your foot valve at the same time. i can do the same test just by cleaning out my air tanks.

 

If you want a serious answer I can give you one.

 

Pump down ? Sounds like something the court came up with on my 2nd divorce .

 

You stole my thunder on wearing out the foot valve. It also lets the person next to you, trying his best to sleep, know your doing a proper pre trip.

 

It also adjusts the self adjusting slack adjusters IF they're working correctly.

 

Somebody give tenman a cookie

Also it will show a bad brake chamber. Year or so ago my trainee was doing the pump down in the morning. I wasn't paying too much attention - a good guy who already shown he knew the difference between left and right and could count past 10 without taking off his shoes and socks. Anywho he says "we lost more than 4 psi". Internally I was thinking this guy may need an eye exam, but I said restart it, this time I watched the gauges. Turns out we a a tractor brake chamber failing. It was fine for the first 30 seconds and then started to slowly leak. Even in the shop you could barely hear it.

 

I did it once in a break check area before a long descent, just to make me feel better

 

It sure took a while for the right answer to show up.

When you hook a new trailer you need to adjust your brakes for that trailer. If you go from an MT to a maxed out paper load, that paper is going to be hard to stop.

Let your air build to max. Push the brake to the floor and hold it for a full three seconds. While holding listen for leaks and see if the needles move. Do it two or three times and you'll notice a huge difference in how well the truck stops.

No need for a full pump down but if you don't do anything a light trailer will lock the wheels easily and a heavy trailer will push you more. You'll love it in the rain.