Tractor will not detach from trailer

This has happened to me several times in the last few weeks with frack tank trailers. They don't have legs and have to be loaded with a forklift. One trailer would unlatch with no issue and the next wouldn't release. The handle wouldn't pull out and I tried moving back and forth and setting and releasing brakes. Nothing worked except having the forklift lift the trailer just enough to release a little pressure.

 

Might be some stupid input here. But here goes.
I didn't see where you said if you're trying to pull it with your hand or using the J bar. You can pull way harder with a J bar. Sometimes they are stubborn and this is often enough extra pull to force it to unlock.

 

That bolt on a Holland is an adjuster for the jaws. Backing the nut off increases clamping, adjusting in creates slack.

Do not...

....DO NOT mess with it unless you know what you're doing and have a gauge!!!!!

.

 

Yeah there's a special tool to adjust that. That's one for a mechanic to do. I learned the way to tell if it needs adjusting is when you get a small gap slowly forming between the nut and the front of the 5th wheel plate. Also told not to ever mess with it myself.

 

This needs to be focused on. People? Hint hint.
I can’t comment. Only drove a truck once with an electrical release. And yes. It also had a manual bar on it.

 

Well this was today at 7:23 pm.. Its been 3 hours, now its 10:34 pm... I pray that you are not still sitting there trying to get the trailer loose?

 

It's also possible there is nothing at all wrong with the 5th wheel. Sometimes a kingpin gets bent. I have seen many trailers with bent kingpins. For some reason some drivers will not take a minute to inspect the kingpin and strike plate before sliding under. This is a great time to take out the permits to make sure they are all up to date. If the kingpin is bent depending on how it is bent it might take a mechanic using a sledge hammer to get it out. These pinpins can put pressure on the release mechanism and you can't pull it far enough to get the jaws to release. Always look at that kingpin and strike plate before sliding under. If it is bent really bad take a photo of it and see what the company wants.

 

Check for second release handle on passenger side of 5th wheel. Our older Kenworths have the dual fifth wheel locks

 

And this boys and girls is why you always make sure when adjusting a fifth wheel plate you're using a new king pin.
I've seen it before where the fifth wheel slack being set on an older trailer nice and tight, made it almost impossible to detach from a new trailer.
Don't know if that's the issue at all, just sharing a thought.

 

Probably not backed all the way back against the brakes or the kingpin is bent . or tractor is at an angle to the trailer that's your 3 main causes ..... mine will do that sometimes where you can pull the pin but not quite enough to lock it open I take a bungee from the handle to the mudflap bracket as far open as you can get it and drive away. ....... if this happens all the time take it in to get adjusted. .... it's a pain in the ### and useually doesn't happen unless it's raining or nasty out