12 Common Semi-Truck Breakdowns You Need To Know

road hazard cone breakdown
Photo by Erik Mclean from Pexels

When you are on the road, you’re making money. When you’re stuck on the side of the road waiting for semi repair, you can start counting the dollars as they drift away. Semi-truck towing isn’t cheap, and it isn’t even the ultimate solution. Semi-truck breakdowns happen in the most inconvenient places to boot.

Knowledge Is Power

The more knowledgeable you are on common big rig breakdown issues, the more likely you are to prevent them, notice them, mitigate the damages, and keep money in your pocket. It isn’t just about the cost of repairs but about your legal liability. What if the mechanical issue caused an accident that was preventable?

The trucking industry is regulated via the Compliance, Safety, Accountability (CSA) section of the Federal Motor Carrier Safety Administration, part of the U.S. Department of Transportation. Not only can they provide you with a wealth of information regarding your safety, but also, they make it clear that you, as the driver, are responsible for the proper care and maintenance of your equipment.

The CSA helps rank the severity of violations that are common causes of accidents. They rank the violations on a scale from 1 – 10. You can see how they calculate their vehicle maintenance BASIC assessment here. Their Safety Management System Methodology publication shows the rankings of the violation severity on the 1 -10 scale on page A-23 in Appendix A in Table A-5 Unsafe Driving BASIC Violations.

If you read through the multiple pages of potential violations, there are over a dozen that are at the 6 Level out of 10 that involve lighting in some way. Preventative measures can be taken to know whether or not lights are working. Is it the bulb? Is it an electrical issue? Ignorance is no excuse when you are answering to a judge, your boss, and your future self.

Diagnosing a Truck Breakdown

Sure, you may not know the problem, but you can make a list of the symptoms. Here is your method for breaking down the issues. Pretend for a moment that you are a full-fledged semi-truck repair technician or mechanic and have been asked to report on the semi-truck breakdown issues. What do you do?

  1. Make a list of any exterior observations. Are there parts obviously missing? Holes? Dents? Anything dripping onto the ground that shouldn’t be?
  2. Does the rig start up? If so, how does it sound? How does the engine feel? Seriously. You ride in this cab hours a day. You should be at one with the sounds, smells, and touch of the truck. The vibrations could tell you that something isn’t right.
  3. Do a system check. I know; you aren’t in a spaceship. However, you basically are and there are a lot of different mechanical, physical, or electrical issues that you could figure out just by walking around the truck, kicking the tires, and flipping a few switches.
  4. How does the truck shift? Are the gears engaging properly? Larger problems may only be noticeable on the road. Mimicking those conditions should only be done if the problems are not in any way dangerous and the situation is safe and controlled.

Once you have compiled a list of symptoms you can figure out what the potential problems are. Symptoms lead to the problem, and the problem can lead you to the solution.

Is It Your Solution Or That Of A Shop?

This is the moment not of knowledge but of wisdom. This separates those with clean records and those with violations. Can you put air in a tire, top off the oil or other fluids, or tighten a lug nut? Most small issues can be done in the Do-It-Yourself fashion. This saves money, time, and energy on everyone’s part. But don’t replace efficiency for quality.

Know your mechanical limits. If you need it done right and you are not sure if you are the one to do it, then you need to get a professional. Remember the old saying: an ounce of prevention is worth a pound of cure. You may know a quick fix, but a harder semi-truck breakdown issue may happen causing you even more money and time.

If you do experience a breakdown and your responsible for your own repairs. Using a service like USA Breakdown can be invaluable. Finding roadside assistance is imperative when you’re on the side of the road. If you’re semi-truck is broke down, try using our roadside assistance search tool.

The Dirty Dozen: Most Common Truck Breakdown Issues

1. Tires

Everyone knows that tires are the leading cause of semi-truck breakdowns. Tire issues are not just the leading cause of breakdowns but account from over 50% of semi-truck roadside failures, as measured by the American Trucking Associations (ATA). What causes semi-truck tire issues relate to the proper physics of a wheel.

It could be an under-inflation issue, or a low tread depth caused by old tires. Low pressure in your tires will cause heat build-up in the sidewalls, which could cause a blowout at a weak point or significant wear.

Low tread depth increases the chances of a puncture due to the exposed skin of the tire. A misaligned axle will always cause non-uniform wearing, which is also a potential issue for blowouts, failures, and accelerated wear.

2. Wheel End Components

Your truck doesn’t float on rubber. It is connected via the wheel to the axle, which turns the world. Your wheel, consisting of the wheel, rods, bearings, nuts, etc., ages and wears extensively. Think of all of those ball bearings constantly circling the rims for hundreds and hundreds of miles.

Replacing and re-greasing bearings on a bicycle isn’t that hard with a little practice. However, you might not even be able to get a lug nut off if it’s frozen or rusted on. Clean and maintain your wheels and tires as they age. Replace them when they need to be replaced and not when you want to replace them. That is how you avoid semi-truck roadside breakdown issues.

3. Brakes

Besides being a top way to kill off a good guy in a movie, bad or worn breaks could be fatal. They have been shown to cause upwards of 29% of all common semi-truck accidents. The semi-truck breakdown issues around a damaged break won’t be your common breakdown unless your situational awareness feels the issues as the develop instead of at the moment of failure.

Your semi-truck’s drums and discs are constantly used on a long haul. All that friction and force will cause wear and tear that will need to be monitored and mitigated. Further, an instantaneous failure may be caused by faulting installation, subpar materials, air leaks, corrosion, overuse and wear, or internal contamination and clogging during freeze-thaw cycles in colder climates.

4. Electrical

If you are getting on the road or are already on the road and you start to see flickering lights, dim lights, or potentially no lights, you can bet that there is an electrical issue. Electricity issues related to bad or damaged wiring can also led to poor connections. You may hear clicking noises from the engine block or consul. Electrical sparks from exposed wiring could cause small burns. That isn’t your musk; that is an electrical short-circuit that could potentially build to an electrical fire.

5. Engine

An old engine with issues, particularly a semi-truck diesel engine issue, won’t just cause a semi-truck breakdown but will take money out of your pocket with decreased fuel efficiency and decrease horsepower. You might not want to overhaul your engine over a long weekend by yourself, unless you are a trained professional. So, a mechanics shop can give it the overhaul that it needs to keep you going.

6. Alternator or Battery

If you have ever had an alternator or battery go bad or die in the winter, then you know the pains of turning the key and nothing happening. That single red light that might light up and not even the slightest of sounds can cause a semi-truck roadside breakdown to last for hours. Most of the issues relating to batteries and alternators are related to either the climate or the driving conditions.

The connections could also be corroded due to climate and wear. Are you part of the Ice Road Truckers? Are you turning the truck on and off constantly? How old is the battery and how much electrical voltage is being pulled at any given time? Watch for flickering headlights right before your alternator goes bust.

7. Clutch Cable

If you don’t exactly know what a clutch cable is don’t worry. Just nod your head as you read this like you know exactly what you are reading. The clutch cable connects the clutch pedal to the clutch lever arm on your transmission. The inner cable covered in an outer sheath allows the transmission to smoothly switch between gears.

It takes it “out of gear” and then engages the new gear as you push and release the clutch pedal. If you start to feel a change in how you need to engage the clutch to change gears, that is a sign that your clutch cable is wearing. Because it is a metal cable it is prone to snapping and causing immediate clutch failures. If the outer sheathing is damaged the inner lubrication could dry up seizing the metal cable in the rubber plastic hosing. You don’t want a semi-truck breakdown issue to require a new clutch cable.

8. Cooling System

On a hot summer day driving through the middle of Texas can feel worse that baking in an oven. Having a semi-truck roadside breakdown issue caused by a bad radiator or hose failure can be the worst type of truck breakdown. There is little to watch for when monitoring your cooling system. The best way to know if there is something wrong is to constantly check your truck’s coolant tank and monitor how well the AC keeps you comfortable.

A radiator issue isn’t just an AC issue. It also helps keeps your engine’s parts at an optimal operating temperature. If that heat sink fails, your engine won’t last long. Invest in the long-life coolants, top shelf hoses, and clamps made for a king.

9. Fuel System

A fuel system semi-truck breakdown issue is the number one most preventable of all semi-truck roadside breakdown issues. Why is it the most preventable issue? You just need to monitor your diesel and your diesel exhaust fluid.

Gas up regularly and make sure you know how far a tank will approximately get you. If you start to see your MPG drop off significantly and there are no other engine issues, you could have a fuel system leak. Just gas up and know how far you can go.

10. Oil Leakage or Burning

Assume you hit a pothole or drive over a tree limb. A rogue rock or branch could puncture your oil pan or a line. An old engine may just have worn connections or washers. Either way, once your engine leaks oil you are bound to have serious semi-truck breakdown issues.

It could be as simple as a hole in a line that just needs some duct tape. Or, you could have run the engine so long that it seizes up. In that case you need to replace the entire engine or rebuild it if you can un-seize the pistons.

Good luck. Either way, oil is flammable. As it accumulates under an idling truck a single spark could turn a roadside pitstop into a roadside breakdown from hell. Watch for smells, oily substances, smoke, or poor engine performance.

11. Suspension

If you’ve ever driven in a “not so comfortable off-road vehicle” then you have probably experienced something with poor shocks. Your truck’s suspension slowly wears preferentially depending on the truck and the uniqueness of the vehicle.

The ball joints of one side could always go first. You need to know this. You need to feel for the clicking and popping of the suspension as you turn the truck or take it on a bumpy road. Constant shaking is obviously bad for the rest of the truck and your internal organs.

12. Exhaust System

With more stringent trucking rules growing in each state, your exhaust system may cause you more pain than you think. It may not be a semi-truck breakdown issue, but it could be a semi-truck sideline issue due to the need to constantly improve and replace your diesel particulate filters.

Take Care Of Your Truck And It Will Take Care Of You

The number one rule in semi-truck maintenance is to know what type of repair or preventative measure is needed. Is it a DIY or some other guy problem? Here are some things you absolutely can do on your own:

  • Fix a broken headlamp
  • Replacing Seals
  • Trailer Crank handle repair
  • Installation of grommets and taillights
  • Replacing mudflaps
  • Topping off all fluids
  • Cleaning the outside of your truck

Anything else that you are not comfortable with should be handled by a trained professional. Here are some final tips for proper semi-truck maintenance.

  • Don’t get the cheapest fix. Get the highest value fix.
  • Always carry a set of tools in your cab.
  • Always illuminate your truck during a breakdown.
  • You are the captain of your ship. Act like one.

Do you have any breakdown issues we missed? Let us know a time when you had a breakdown issue over the road in the commons!


Former Driver, Maintenance Coordinator, lover of all things technical. Eli writes for USA Breakdown covering multiple topics and breaking news in the trucking industry.

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