Troubleshooting Demco Hijacker Jarring and Chucking at Start and Stop

Updated 06/10/2025 | Published 03/21/2018

Question:

apparently have one of the earlier versions of the 18K demco hijacker, no matter how many times I adjust it, when I have come to a stop and then take off it feels like there is slack in something and it jerks and pops , it operates fine except that, is it the design with just the locking bar or something else ? I see the new head has a traditional locking device, and looks more secure, was wondering if this is a fix for the clunking ?

asked by: Gary G

Expert Reply:

I reached out to my contact at Demco and he said that depending on the year, there was a gear adjustment bolt on the cab side of the base of the older Hijacker models. He also said some of the slide bar heads had an adjustment bolt there as well for a better king pin/pin box connection. These adjustments should clean up the slop that you are experiencing. If you have your owners manual it will walk you through those adjustments. If you don't have the manual, let me know your model number and send a photo and I'll see what further troubleshooting we can do.

expert reply by: Jason S

To M.

6/9/2025

What way do you do? Adjust the bolt to stop the jerking

Kate F.

6/10/2025

@ToM Since you have the older version with the locking bar design, there is going to be some slop in the jaws. The thing is, that locking bar can sometimes leave a little slack or play between itself and the king pin. It’s not dangerous, but it can create that annoying feeling like something’s shifting around when you stop and start. It’s especially noticeable in heavier trailers or under load. There are a couple of things you can try to reduce the jerking. On many of those bar-style hitches, there’s a small adjustment bolt that controls how snugly the bar fits around the king pin. You can tighten that just a little bit, like 1/8 of a turn at a time, until it holds things more securely. Just be careful not to overdo it, since overtightening can affect how the latch operates or even wear on the pin. Also, it helps to inspect the bar and channel for any visible wear and give everything a good cleaning and lubrication with fifth-wheel grease. Dry metal surfaces can exaggerate movement, and a bit of lube goes a long way in smoothing things out. If things are still clunking after that and you want to look into getting a new hitch, let me know your year, make, model, bed size, and if you have the OEM Prep Package or not so I can find a better hitch for you.