5 Bad Kingpin Symptoms: Easy Ways To Identify

A kingpin is a crucial part of any trailer-supporting vehicle, especially a tractor. It helps a driver to carry loads easily using the trailer.

However, it’s tough to use the trailer with a damaged kingpin. Driving with a damaged kingpin can result in a severe accident. Do you want to know about the bad kingpin symptoms?

Facing coupling problems, jammed to the supporting vehicle, worn-out shoulder, damaged kingpin throat, and improper lubrication are the prime symptoms of a defective kingpin. It’s better to replace the rusty and damaged kingpin with a new one to avoid accidents.

If you want to replace the kingpin, first diagnose it thoroughly. Sometimes, other vehicles like CJ or TJ parts are responsible for various issues, but the kingpin gets the axe.

5 Common Symptoms Of A Bad Kingpin

common signs of bad kingpin

A defective kingpin can’t join the trailer to the vehicle; instead, it makes the situation more complex. That’s why you should be familiar with the general signs of a damaged kingpin. Knowing these prime signs will help you to fix the issue quickly.

1. Coupling Issues

It’s tough to couple the trailer to the car with a bent kingpin. Mostly, the kingpin is at fault while facing issues connecting the trailer to the vehicle. Many times, the coupler structure gets damaged with time, causing this issue.

coupling issues

Remember, dented kingpins can’t support the trailer as well as the loads in it. So, if you’re facing a loading issue with your trailer, the kingpin is the culprit.

2. Stuck With The Supporting Vehicle

Another prime symptom of a defective kingpin is you’ll have to apply heavy force to detach it from the joint. It’s somewhat similar to bent kingpin issues but more challenging and tough to solve.

Consequently, it damages the fifth wheel and 17 or 20-inch wheels. Facing difficulties while transporting goods is another indicator of a destructive coupling that may lead to air brake chamber problems.

3. Damaged Shoulder

If you don’t fix the previous issues, it’ll lead to a damaged shoulder. An injured shoulder can’t adjust the fifth wheel, resulting in a free fifth wheel. So, hauling or pulling campers becomes almost impossible because of the worn-out shoulder.

4. Poor Lubrication

It would be best to lubricate the fight wheel and vehicle connection to avoid excessive wearing. An uneven wear in the kingpin generally confirms the lack of lubrication between the connections.

poor lubrication

Sometimes, the kingpin wears faster than usual due to insufficient lubrication. Consequently, it creates poor connections between the trailer and the car. Sometimes using Woolwax or fluid film might give you an easy solution to this issue.

5. Defective Throat

Fixing the damaged shoulder and the kingpin’s neck can fix your coupling issue, but it’s impossible to fix the throat. You can’t adjust your fifth wheel when the throat is severely damaged. Moreover, longtime kingpin problems also bring rattling issues over bumps in your jeep or rocky ridge truck.


A defective kingpin can’t deliver the actual performance. Plus, it’s pretty risky to use for serious tasks. If you want better performance and to avoid accidents, install a new kingpin ASAP.

We hope the analysis of bad kingpin symptoms has given you a clear thought regarding the issue. Lubricate the kingpin properly with better-quality oil to prevent rusting. If you see the throat is cracked or damaged, change it ASAP. Performing regular maintenance helps to avoid rusting and cracking of the kingpin.