flat tire on a semi trailer

Common Semi Truck Breakdowns and How to Fix Them

Semi trucks can last running an average of 750,000 miles. This is equivalent to a lifetime of 15 to 16 years if the truck covers 45,000 miles annually. Yet, they are prone to breakdowns and are subject to wear-and-tear. If you are a long-time trucker, chances are you have encountered a semi-truck breakdown once in a while. Such a breakdown can mean dollars drifting away. It also means extra cash coming out of your pocket to have a repair. So, it pays if you are familiar with the common semi-truck breakdowns and what you can do to fix them.

8 Common Semi Truck Breakdowns

Bad Alternator or Battery 


The most common scenario for a bad alternator or battery is a trucker parking the semi-truck for an overnight stay. After waking up in the morning, that truck engine won’t start. A semi-truck’s battery can last for 3 or more years. While its alternator can last up to 7 years. If the engine produces a clicking sound, most likely, you’ve got a bad battery. If the engine produces a whining sound, then it’s a bad alternator. 

The best way to check if your truck’s battery is still working is by using a voltmeter. A normal battery reads between 14 to 15 volts. To check if your alternator isn’t working, run the truck and unplug the battery’s positive connection. If the truck stops, there’s a problem with the alternator. Jump-starting the truck is the quickest solution to troubleshoot a bad alternator or battery. It allows the engine to run to reach a garage or repair shop.

Brake Troubles


The most common brake troubles that truckers encounter are either spongy, squealing, and stiff brakes. A spongy brake may be caused by a fluid leak. Check the level of your brake fluid reservoir. Top it up if it’s in a low-level mark and quickly drive to the nearest garage or repair shop. A squealing brake may be due to insufficient brake lubrication or low-quality brake pads. Try using a WD40 to grease the brake caliper piston, caliper bolts, pads, and rotors.

Clutch Problems 


The most common clutch problems among heavy-duty trucks are difficulty with pedal movement and slipping clutch. A difficult pedal movement on the clutch may be due to broken compression springs, which you can easily DIY to replace. While a slipping clutch pedal may be due to oil leaks. Cleaning any oil residue in your clutch assembly can resolve the issue.

Electrical Malfunctions


Dim lights, flickering lights, or totally no lights are common electrical malfunction among trucks. They can either be caused by a faulty fuse, loose spark plugs, or loose electrical wires. The basic troubleshooting to such a problem is identifying the root cause. Once you identify them, you can easily DIY change the faulty fuse or reconnecting the loose spark plugs or wires.

Fuel Leaks


A leaking fuel system is very dangerous among truckers. At the same time, it can be a hazard to the environment. Fixing a fuel tank leak can be done at home within a day. Be sure to follow the instructions carefully when using either an epoxy or a sealant. It is also important to clean the tank with a degreaser before doing the fix.

Oil Leaks


Oil leaks increase the risk of an engine failure or a vehicular fire. Oil leaks can happen anywhere within the semi-truck’s engine. The very first thing to do is crawl under the car and check the oil pan drain plug and seals. Then, check the gaskets of the valve cover and the seals of the timing cover. If you have found a leak, use a stop leak additive to temporarily seal it. If the leak is coming from a loose bolt, the best fix is to grab a torque wrench to tighten it. 

Overheating System


The crazy hot summer and prolonged driving trips can cause a semi-truck to overheat. It may be due to a bad radiator, a broken hose., or a coolant leak. Adding more water to your radiator can temporarily resolve the issue. If the problem is a broken hose, you can easily replace it, while a chemical sealer can cover coolant leaks.

Tire Problems


The most common truck breakdown that truckers encounter is a blown or deflated tire. This is also the easiest to troubleshoot because most semi-trucks have spare tires. A deflated tire can easily be addressed by using a tire puncture sealant and adding the correct air pressure on it using an air gauge. While a blown-up tire needs immediate replacement. Remember, the average lifespan of semi-truck tires is 3 to 6 years.

In general, the best way to avoid breakdowns on your semi-truck is to maintain it properly. A truck maintenance checklist can guide you on what to do and when to do it. Always remember, “Prevention is better than cure.”

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