There's a couple reasons why auto slackers don't keep a brake in adjustment.

The most common reason, nobody seems to know they have to stroke the pedal with a FULL application several times, this should be done daily with a min. of 90 psi. This is how the brakes set up, the spring brakes will not set the brakes up.

It's a wonder more people aren't killed by trucks.

 

 

Too funny.

Btw, I'm pretty sure I flunked the knowing-when-to-keep-it-to-yourself test.:surrender:

 

That part right there? That IS part of your pre-trip inspection.....if you think about it. Test the tractor brakes separately from the trailer brakes.

 

I just got T-boned 2 weeks ago in a Petro by a Fly-By Night Florida (Cuban?) truck/nospeakEnglish driver that was unattended. Truck just decided to roll forward right when I was leaving. I couldn't get out of it's way fast enough. Hit my trailer and blew out the tires/rims, F-ed up toolbox and axle alignment then hit another truck before it stopped.

Could have killed someone.

 

Sounds like to me you need to adjust your brakes.

 

There is also a possibility that another truck may have backed his trailer into yours. If they match up and are not at any angle, no damage is done, or at least not noticeable. But, that can push a truck that has both the tractor and trailer brakes set. It's also something I've seen happen far more than once at a Pilot. Especially if it has the normal cramped space in the lot. A guy backs out of his spot and across, and into the truck on the opposite side. That might have happened to you. Be sure and look at the back of your trailer. If a box, look at the bars that lock the doors and see if they've been bent into the doors,

 

The plot sickens.

First understand. Years ago I lived next to a store and when trucks would make deliveries I quickly learned to detest two sounds. The sound of air brakes releasing air when the driver sets the emergency brake and the sound of a truck idling when I'm trying to watch the best part of a freaking movie.

The other day I pulled away from a dock to close my doors and it was a residential neighborhood. I can't help but try and be as quiet as possible. With my thumb against the red (trailer) plunger, I pulled the yellow plunger to set the emergency brake. The red one started to pop too because I didn't have enough pressure on it and when it got maybe half way out I reacted and pushed it back in with my thumb. The curious thing is that I didn't hear any release of air at all. Is the dashboard valve thing bad? Faulty driver execution of a simple procedure? Driver breathing too much diesel fumes and maybe should try a different profession?

Btw, the brakes were adjusted after the first incident.

Also, I should probably say that I'm sure not knowing how to diagnose what is probably a simple mechanical problem will keep me out of the Truckdrivers Hall of Fame, it's probably good to post this. I can't be the only one to get fooled by a problem like this and if it saves someone getting hurt I will have done my good deed for this life and I can go back to being a useless drain on society. :smokin: