53' dry van wheels will move without air?

Hey guys title says most of it. I have a 53ft dry van it is definitely on the older side but well maintained. I went to a warehouse where they want you to drop your trailer and leave it there. They move it to a dock etc etc. Well I get a call that they don't like my trailer because they can move the tires without air to the brakes. The brakes are only about a year old. So I go check it out and they definitely can move the tires some if they pull hard. The brakes are definitely dragging but they don't lock up the wheels. The yard person was saying they shouldn't be able to move the trailer at all. I adjusted the brakes some but it didn't help the issue much. The brakes really aren't complicated on these trailers so I don't know how to fix the issue? The trailer wasn't moving easily and the brakes were definitely squealing when they pulled. Any ideas how I can make it so the trailer doesn't move at all? Seems silly but I haul to this place some what regularly.

 

Yeah trolly handle will lock up the tires no issue. I can slide the tandems or drag the tires if I want. Seems to be a parking brake only issue.

 

Thanks for the trouble shooting sheet. I'm assuming the air isn't 100% releasing. This is my first assumption. I will just have to see which valve is doing what back there. The brakes and s-cams are pretty new and they were adjusted within spec. I adjusted them outward some for some more pressure but still didn't keep the trailer from being pulled. They still decided to unload the trailer so I will have to dig into it when I get home. The brakes work just fine every other way. Service and trolley are great.

 

It would have to be all 4 if that was the case and one is only a few months old. The others aren't super old either. Have all been replaced in the last few years. Nothing on the trailer is super old.

 

That is going to be my check when I get home. I don't remember what all the valves look like back there. I know there is one I replaced before and I thought it was the parking brake one. It releases air when you set the brakes. So I'm assuming it is that one. I had issues with it leaking awhile back and pulled it all apart and cleaned it. Maybe I should grab a new one. I don't think there was any other valves back there.