Can someone explain to me why some drivers keep the red one out?

I have a question that sort of pertains to this thread, was sitting next to a reefer fueling the other day, as he came in I could hear him dump both stop valves, and then the trailer air BAGS dropped.

It was like his trailer air bags were set to drop anytime the brakes were popped, do some companies do this so there is no stress on the trailer when unloading at the dock? It's the only thing that made sense to me, yeah, I know I should have asked him, but I didn't.

Educate me.

Thanks Stan

 

If you've ever seen Ice Road Truckers, you'll see those guys crawling under the trailers to beat on the brake drums to loosen them from the ice. These are typically trailers that were dropped and thus their brakes were locked up over night or whatever in the ice conditions.

What you can do is get yourself a little propane torch that screws right on one of those 16 ounce propane bottles, self lights and crawl under there and dry out your brakes in such a case.

Works well for frozen landing gear too.

These guys lit a fire under their engine to warm it up--

 

Seen lots of megas wagons do this and while I would personally hate it--best explanation I've heard is it is done to insure trailers cannot b dropped with bags inflated--

 

As well as the drums freezing up.
A lot of my companies trailers have automatic dump valves for the air ride.
You pull the red valve. It dumps all the air in trailers air bags.
This is to prevent dock walk.
Takes a minute to resupply and rebuild secondary air pressure.
If just wheeling in fuel island or some other level place I might just pull parking valve.

 

With trailers that have dump valves, if you back into a dock tight against bumpers. And set both brakes at same time. The whole combination will actually move away from dock a couple inches as trailer drops it pushes truck forward.
So reverse. You bump dock. Set trailer brakes. Let trailer settle. Then set tractor brakes. That keeps it tight against dock. And takes tensions of kingpin and 5th wheel jaws.
Seen many guys wrestle releasing 5th wheel after the trailer drops air.

 

I was just curious, since we never bump a dock I just didn't know.

Thanks Stan

 

I use to pull both till I went to air ride trailers. Our trailers dump all the air when you pull the red valve. It takes a very long time to air back up if you're heavy plus you'll need to raise your rpms to air your tanks back up on the truck, for me anyway as if I'm loaded heavy and push the red valve in it drops my air to about 80psi when the trailer is fully aired.

Plus it says on the red valve it's not for parking. So the only time I ever pull the red valve is when I'm dropping the trailer or when being loaded/unloaded the customer may ask to have the air dropped.

 

Yes, Mine does say Not for parking, and that would be for the person who pops the red Trailer brake and Not the parking brake. Then release the pin and watches the truck roll away. I have seen that happen to a driver before.

 

tractor only.

the only time i set the trailer breaks is on a incline and i only do that because i only have 2 spring breaks on the tractor.

as others have said never set the trailer breaks in the winter unless you feel like swinging a hammer.

 

Only time I ever apply both brks is when parked on a hill.For instance when I unload hides.I park by the door,run in to see what dock.I set both brks because that part on the lot is on a slant.Rather be safe then sorry.Directly behind my trl is the guard shack.That would be devistating if 77 thousand pounds of hides hits the guard shack and whoever is in the way.