A Guide to Kingpin Replacement

A Guide to Kingpin Replacement

Trailer kingpins are crucial to smooth operation and secure tractor/trailer couplings. They should deliver exceptional strength, balance, and wear resistance for miles. However, there will come a time when repair or replacement is necessary. 

Here’s what you need to know about the kingpin replacement process.

How to Tell If Your Kingpin Needs Replacing

The most common signs of a faulty kingpin are:

  • Difficulty coupling
  • Difficulty uncoupling
  • Worn down throat (see Item 1 in this document)
  • Worn down shoulder (see Item 2 in this document)
  • Premature wear from lack of lubrication

It’s also important to understand that aggressive, non-compliant coupling attempts may bend or damage kingpins. If you have not followed standard coupling protocols, your kingpin may be in poor condition. 

How to Inspect a Kingpin for Replacement

Kingpin inspection is fairly uniform. Kingpins are built to SAE dimensional standards. Reference linked JOST document LT_KZ003-00_A. Kingpin replacement procedures vary from vehicle to vehicle. You can reference TMC RMP-750 to determine how to best inspect your kingpin and upper coupler. 

Bolt-in upper couplers are most common on tank trailers, while most van and flatbed trailers have fabricated structures, including kingpins and upper couplers. Regardless, here are the steps you’ll loosely want to follow: 

  1. Cut out the upper coupler plate welds
  2. Cut the kingpin from the cross member structure
  3. Remove any bent or corroded cross members

At a minimum, a damaged, worn, or warped upper coupler plate and kingpin will need to be replaced.

How Long Does It Take to Replace a Kingpin?

You might be wondering how long your trailer will have to be in the shop for a kingpin replacement. This depends on your upper coupler’s design and the extent of the upper coupler structure damage or corrosion. 

A bolt-up upper coupler and kingpin can be replaced within just two hours, while a fabricated upper coupler plate may take up to eight hours of labor. These timelines may be extended to a few days in severe cases involving structural cross members and floor structure. 

How Much Does It Cost to Replace a Kingpin?

The cost of kingpin replacement can also vary based on a number of factors. You’ll want to consider things like: 

  • The extent of structural fatigue or wear 
  • Your trailer’s OEM upper coupler design complexity
  • The cost of service and installation, plus the replacement part itself

Keep in mind that the replacement cost is well worth it for a high-quality kingpin replacement. Find a manufacturer that promises quality, so you can get longer-lasting value and minimize damage in the long run. 

Trust JOST International for Steel-Forged, High-Strength Kingpins

For quality, strength, and safety, choose JOST. JOST kingpins have proven themselves mile after mile, all across the world. They’re steel forged, offering outstanding wear and impact resistance. Find a dealer near you.

How to Identify & Complete the Most Common Fifth Wheel Repair

How to Identify & Complete the Most Common Fifth Wheel Repair

Just like any other piece of trucking equipment, fifth wheels require regular inspection, maintenance, and repair. Often, problems found during inspection can be attributed to the same component. Below, we’ll discuss what the most common fifth wheel repair is and give you some quick and simple tips for how to fix it.

What Fifth Wheel Part Most Commonly Needs Fixing?

The fifth wheel part that most commonly requires repair is the top plate. The top plate is a horseshoe-shaped plate that’s attached to the main frame of the vehicle. It offers trailers and cargo a secure connecting point for heavy loads. 

Why is the top plate the most common fifth wheel repair? It’s under intense stress while in use. This high stress can damage the plate and normal wear can break down internal, smaller components like lock jaws and cushion ring inserts, bushings, release handles, and more to the point of replacement. You may also struggle with fifth wheel top plate troubles if your coupling attempts aren’t in compliance with JOST’s Operating Instructions or the industry standard TMC RMP-654.

All of these possibilities show why following standards and being proactive about inspections and maintenance is key.

Troubleshooting: How to Inspect & Repair a Fifth Wheel Top Plate

Should you have an issue with your fifth wheel top plate, here are the steps you can take to diagnose and fix the problem.

1. Review the Top Plate’s Surface

Pull the release handle out and hang it on the release notch; it must be flat and straight. Then ensure the adjusting screw shows ⅜” to 1 ½” of threads. If it shows less or more than that, there is an issue. 

If no issue is found, scrape any excess grease from the top plate surface’s recessed center. Check the cushion ring insert for any chipping or damage, and make sure the locking bar tip protrudes further into the throat than the coupling guide lugs.

2. Review the Lever with the Bushing Under the Top Plate

You can also inspect your top plate and diagnose any issues by looking underneath it. First, verify that the lever with the bushing is in appropriate condition and position. Then check the pivot bolts to ensure there’s one washer between the lever and castellated nut on each of them. Finally, check the release handle attachments to ensure proper attachment.

3. Use a Lock Tester to Check Operation

A third and final inspection is to use a lock tester to check operation. Start by engaging the lock test tool to lock the fifth wheel, then verify that the release handle is in the locked position (Document Link). 

Also, note the lock jaw and locking bar positioning. The lock jaw must accept the kingpin and fully rotate. The locking bar must fully cross the throat. If one of these positions is incorrect, replace the damaged Lock Jaw, Lever, or Release Handle. 

Once you’ve determined what is worn or damaged, you can either fix or replace it. 

Watch this video or download this troubleshooting guide for more information, visuals, and commonly stocked top plate repair parts at JOST. 

Repair vs. Replace: How to Know When It’s Time for a New Fifth Wheel

In many cases, a quick top plate repair can get your fifth wheel back and better than ever. However, there are some instances where a repair won’t do enough and it’s time to completely replace your fifth wheel. 

How do you know which is best? Follow these guidelines. 

Repair if: 

  • Your top plate is still mostly in good condition, and a quick or simple fix will get it back to normal. 
  • Your top plate shows some wear but still has good grease grooves and no unsalvageable damage.

Replace if: 

  • Your top plate surface is worn down to the grease groove at any point (see Page 1, Item 1, Figure 1 of this document).
  • Your top plate’s casting is cracked. 

Get World-Class Truck and Trailer Products From JOST International

Time for a fifth wheel replacement? Contact JOST International. We’ve been manufacturing fifth wheel coupling devices across the world since 1956 and have continued innovation ever since. From our unique locking mechanism to our new sensor fifth wheels, our products are the standard option at every OEM. 

Visit this page to order your replacement today.

Here’s Your Complete Guide to Fifth Wheel Coupling

Here’s Your Complete Guide to Fifth Wheel Coupling

There are several critical safety aspects to heavy vehicle combinations, one of which is couplings. Understanding fifth wheel couplings is vital to the safety and efficiency of any trucking fleet. We’ll dive into the world of fifth wheel coupling and what some of the best products on the market currently offer. 

What Is Fifth Wheel Coupling?

The technology of fifth-wheel coupling provides the connection between a semi-trailer and the towing truck, tractor unit, leading trailer, or dolly. A fifth wheel connects the two components, allowing them to articulate, move around, and steer comfortably.

Without a fifth wheel, it would be almost impossible for a semi-truck to make a turn. A fifth wheel evenly distributes weight between a semi-tractor and trailer so you can hit the road and navigate your equipment. 

What Does a Fifth Wheel Coupling System Consist Of?

As a whole, the fifth wheel coupling system consists of the fifth wheel and the kingpin.

  • Fifth wheel – This equipment is a flat, non-rotating horseshoe-shaped coupling device installed on the semi-truck tractor.
  • Kingpin – A metal component that protrudes from the trailer that’s frequently referred to as the “pivot point between the tractor and semi-trailer.” The kingpin on the trailer installs into the fifth wheel on the tractor. The semi-trailer’s surface, with the kingpin at the center, rotates against the upward-facing fifth wheel. 

Invest in High-Quality Coupling Systems With Advanced Technology

When you need to invest in high-quality coupling systems with top-of-the-line technology, look no further than JOST International. Our JSK37UBK Series wheel is revolutionary – it allows the driver to know when the fifth wheel is properly and safely coupled from inside the cab. The sensor technology in the wheel sends a signal to a display in the cab that lets the driver know when the wheel is properly coupled.


  • Throat Illumination (sold separately) – An LED Light shines into the throat to allow clear inspection of the coupled fifth wheel. 
  • Go Light – A green light indicates the fifth wheel is properly coupled, with both kingpin and handle in the locked position.
  • No-Go Light – A flashing red light with an audible alert indicates that the kingpin and/or handle are not properly coupled. 

Capacities & Ratings:

  • Maximum Vertical Rating: 55,000 lbs
  • Maximum Horizontal Rating: 150,000 lbs

How It Works:

  • The Loc-Light system enhances your JOST fifth wheel with the addition of our two-sensor monitoring system as well as a LED throat illumination. 
  • The dual-sensor system is connected to the Go/No-Go indicator light located next to the handle. A proper coupling with the handle and kingpin in the locked position will be lit up as green or “Go light”. If the system does not detect the handle and/or kingpin in the proper locked position, the light will flash red or “No-Go light” 
  • The throat illumination light option (sold separately) automatically turns on when the system is engaged. The light shines directly into the throat of the wheel to provide a better view of the lockbar for pre-trip inspections.

If you need to know how to couple and uncouple JOST fifth wheels, take a look at our instructional video.

Looking For More Coupling System Information?

If you’re looking for more information about JOST International’s coupling systems and top-notch technologies, contact us today. Our experienced team members would happily listen to your needs and share how we can help. We offer an expansive range of fifth wheels, kingpins, turntables, landing gear, coupling systems, and more. 

Follow This Fifth Wheel Inspection Checklist Before Hitting the Road

Follow This Fifth Wheel Inspection Checklist Before Hitting the Road

When you want to set yourself up for a safe, successful trip, performing a thorough fifth wheel inspection is key. It can be a little daunting but necessary for any semi-trailer driver. We’re here to help walk you through the complete fifth wheel inspection checklist. 

What Is a Fifth Wheel Inspection Checklist?

A fifth wheel inspection is a process of carefully examining your vehicle and its components and systems. This checklist usually takes about 15 minutes to complete and is required by the Federal government. 

Why Are Fifth Wheel Inspections Important?

If you’re a semi-trailer driver, you know that the job comes with a lot of responsibility, which isn’t as easy as it looks. Performing fifth wheel inspections before trips is essential for many reasons, including:

  • Safety – Driving a semi-trailer can be dangerous. According to the Bureau of Labor Statistics, drivers of heavy trucks and tractor-trailer trucks suffer fatal accidents more than any other occupation. Making sure all your equipment is in proper working order can be the difference between a safe trip and getting into an accident.
  • Maintenance – Performing the checklist allows you to find minor issues before they become serious. This can save you money on maintenance by solving problems before your trucks get on the road.
  • Compliance – Pre-trip inspections keep you in compliance with the Department of Transportation regulations. In the case of an audit, the DOT may review your pre-trip inspection checklist to ensure they have been filled out correctly. 

What Does a Fifth Wheel Inspection Checklist Include?

You must thoroughly check each major system when performing your fifth wheel inspection. This process includes:

Engine Compartment

  • Check for leaks in the engine compartment.
  • Ensure every component is properly mounted and secured, including the water pump, power steering pump, alternator, front suspension system, and front brake system. 
  • Look for leaks in hoses.
  • Make sure all the tires, rims, and axles are in good shape and working correctly.

Fuel Tank And Battery Area

  • Inspect fuel tanks, caps, batteries, and exhaust systems and ensure they’re working properly.
  • Ensure mirrors, door hinges, and door handles are not damaged.
  • Look at the exhaust system, driveshaft, catwalk, frame, cross members, and gaskets for any malfunctions.
  • Check that the suspension system, brake linings, changers, slack adjusters, and pushrods are properly working.

Coupling System

  • Ensure that electrical lines and airlines are good to go.
  • The fifth wheel should be greased appropriately and have no gap between the fifth wheel and the trailer apron.
  • Make sure the skid plate of the fifth wheel and apron of the trailer are working properly.
  • Inspect the kingpin, mounting bolts, and locking pin. 


  • Check that landing gear, frames, cross members, mudflaps, and the rear door are ready for travel. 


  • Inspect turn signals, four-way flashers, brake lights, high beams, low beams, and brake lights.
  • Ensure that reflectors, reflective tape, and the color chamber are in good condition.

Fifth Wheel Inspection Checklist Resources

If you want more resources regarding fifth wheel inspection checklists, we’ve provided some below.

Check out our helpful JOST International instructional videos to make sure your fifth wheel, landing gear, and coupling systems are in proper working order. 

Take a look at this helpful Semi-Trailer Pre-Trip Inspection Checklist. In addition to ensuring your fifth wheel, landing gear, and major systems are in good working order, you should also inspect these elements of your semi-trailer before embarking on a trip. 

fifth wheel inspection checklist sheet

JOST International Is Here for All Your Semi-Trailer Needs

Once your pre-trip inspection is complete, you’re ready to hit the road! If you need any replacement parts for your semi-trailer, look to JOST International. We have a long history of developing efficient, safe, and innovative systems for trucks and trailers, including fifth wheels, landing gear, coupling technologies, kingpins, and more. 

What Is Semi-Trailer Landing Gear? Here’s Everything You Need To Know

What Is Semi-Trailer Landing Gear? Here’s Everything You Need To Know

When it comes to the parts and equipment of a semi-trailer, the landing gear is extremely important. Do you know how it works? We’ll dive into semi-trailer landing gear and explain how they work, plus where you can purchase this high-quality equipment. 

Everything You Need To Know About Semi-Trailer Landing Gear

In today’s world, there are many landing gear products on the market to choose from. If you aren’t familiar with the benefits and options available to you, you’re in the right place. 

What’s the Job of Landing Gear on a Semi-Trailer?

Trailer landing gear is the retractable support equipment that keeps a trailer level when it’s uncoupled from the semi-tractor. It’s located at the front of the trailer and will keep you and your truck safe. The landing gear consists of two legs that can support the heavy weight of the trailer. 

How Does Landing Gear Work?

The landing gear is also known as “the stabilizers,” and they should be of suitable capacity with a gear mechanism and be able to lift the loaded trailer when required. A pair of landing legs are fixed near the front end to support the trailer after it is uncoupled from the tractor. 

What Are the Benefits of High-Quality Landing Gear?

The leg with the JOST internal gearbox and the crank is called the driving leg, and the other is called the driven leg. The two legs are connected by a central transmission rod known as a cross shaft. To raise or lower both legs at the same speed, simply rotate the crank clockwise or counterclockwise. Always make sure you shift the JOST crank and input shaft out to engage the low gear when raising the trailer and cargo weight.

When you invest in high-quality landing gear, you’ll experience a variety of benefits, including:

  • Improved driver safety
  • Increased driver productivity
  • Lower risk of workplace injuries
  • Keep equipment safe and secure

What Landing Gear Is Offered by JOST International?

JOST International offers an array of landing gear models; each made for varying applications to meet your needs. Some are made for light and heavy-duty, with a gearbox or without a gearbox, and with a spring or without a spring. No matter what type of landing gear you need, we’ve got you covered here at JOST International. 


JOST semi-trailer landing gear

Look To JOST International for All Your Landing Gear Needs

Do you need high-quality semi-trailer landing gear? JOST International is here for you. If you’re looking for superior landing gear from an industry-leading manufacturer, our landing gear meets or exceeds international standards for OEMs and fleet use in North America and internationally. Plus, we use top-of-the-line technology, so you can always trust that you and your equipment will stay safe. 

Browse the full catalog from JOST International and find landing gear for your job today. 

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