Broken Couplings & Jackknifed Trailers

Broken ring couplings and pintle hooks are often the result of a jack-knifed trailer incident. Jackknifing often occurs while reversing and causes severe damage to your trailer drawbar, its coupling, and your tow vehicle.

This is part of the Couplemate™ Technical Hub unit: Towing Trailers & Caravans.  

What is Trailer Jackknifing?

Trailer jackknifing is a common issue that commonly occurs when reversing a trailer. The driver, often unaware, may unintentionally reverse the trailer into dangerous angles. The result is often severe damage to both the vehicle and the trailer itself, including the:

• Rear bumper,
• Trailer coupler,
• Trailer tongue, and,
• Camper chassis.

Many drivers are unaware that they’re not reversing their rigs correctly. Jackknifing typically occurs when the trailer begins to move at sharp angles, and the driver, feeling resistance, attempts to reverse further. This seemingly harmless action often worsens the problem, leading to extensive damage.

Over time, these small mistakes add up, causing harm that might not be immediately visible to the driver. Often, these drivers remain unaware of the damage they’ve caused, such as fractures in the coupling or damage to the vehicle’s rear.

Importance of Correct Reversing Techniques

When I was learning to drive in 1970, I had no idea how to reverse a trailer properly. I was able to reverse park a car without issues, but had I been asked to reverse a trailer, I would have likely failed the test. Sadly, this lack of instruction is common among many drivers of the past.

Today, though, caravan driving courses are widely available. These courses teach drivers essential skills, including how to reverse a trailer safely and avoid common mistakes that can lead to jackknifing. I highly recommend taking advantage of this training. The instructors are experienced, and they have valuable tips and techniques that can prevent costly and dangerous errors.

Damage Caused by Jackknifing

When a trailer jackknifes, it can lead to significant damage to both the vehicle and the trailer. A few common problems include:

• Chassis and frame damage: Misalignment caused by jackknifing can affect the structural integrity of both the vehicle and the trailer.
• Coupling damage: The trailer’s coupling mechanism can become broken or damaged, compromising its ability to stay securely attached to the vehicle.
• Linkage issues: Broken or damaged linkages might go unnoticed, but they can cause further issues with the towing setup.

One of the most concerning problems is when a driver unknowingly causes hairline fractures in the trailer coupling. These fractures, though small at first, can accumulate and eventually lead to a coupling failure, sometimes causing the trailer to detach from the vehicle.

We know of instances where drivers back into the coupling, causing hairline fractures in the coupling head. These factors accumulate and cause multiple until the coupling fails and detaches from the vehicle.

Real World Examples of Damage

I’ve come across stories where drivers, attempting to reverse into tight spots, have damaged their trailer couplings and other components. Over time, this damage can accumulate, resulting in catastrophic failures. In some cases, it even leads to detached trailers—something that can cause serious accidents or even loss of life.

For example, I’ve heard of situations where drivers didn’t realise the coupling had been compromised. While the owner initially thought the coupling had simply failed, X-ray analysis showed that there were multiple fractures from repeated stress caused by driver errors.