The Most Common Forklift Repair Issues & How to Avoid Them

Forklifts are complex pieces of equipment that rely on hundreds of individual components to operate smoothly. Even small issues, like buildup on a connection piece or a loose seal, can lead to hours of costly downtime or create a hazardous work environment.

Fortunately, you can prevent many forklift issues with a little routine maintenance, and some basic troubleshooting can help you identify and make repairs as needed. These are the most common forklift issues you might experience.

1. The Forklift Is Not Starting 

A forklift that won’t start can make all the difference between finishing a project on time and experiencing downtime. Identifying the cause takes a little troubleshooting:

• Check the fuel supply: If your forklift runs on gas, diesel or propane, make sure the tank is filled enough. Some machines won’t start unless the fuel reaches a certain volume in the tank. If you have enough fuel and the forklift won’t start, make sure the fuel itself isn’t too old. If it’s been sitting stagnate in the tank for a while, it won’t be much help — consider using a fuel stabilizer in the future to help protect gasoline from breaking down too quickly. If your tank is consistently running out of fuel without apparent cause, inspect the fuel lines for leaks or damage.
• Inspect the battery: Electrical forklifts rely on a battery to operate, so you want to make sure it’s fully charged and ready to go before operation. If it’s not holding charge, check that the connections are secure and free of corrosion or buildup. Batteries can also get too cold if your forklift has been sitting in extreme temperatures. If none of these fix the problem, it may be time to replace the battery. Protect your battery from future issues by storing your forklift in a temperature-controlled environment when possible and regularly inspecting all connections and terminals. Make sure the last operator to use it leaves the battery to charge before the next shift.
• Replace the coolant: Forklifts can overheat, just like regular vehicles. In most cases, replenishing the coolant should do the trick. You can check the current level through the coolant reservoir. When refilling, be sure not to exceed the maximum fill line.
• Clean the radiator: If your forklift is still overheating even with adequate coolant, the radiator could be clogged or blocked. This is common if you primarily operate outdoors. Check each of the ports and clean any buildup with fresh water. Make this a regular part of your maintenance plan to protect against future overheating.
• Check security features: Some forklifts will not turn on until certain safety parameters are met. For example, yours may not start until it detects someone sitting securely in the seat. You should also check that the gear level isn’t in neutral and the emergency power off button isn’t still activated from previous use.
• Test the spark plugs: If your forklift is trying to start but keeps turning over, use a spark tester to check the spark plugs. If the tester shows no spark or glow at the tip when you turn the engine on, you likely need new plugs. Inspect new plugs for microcracks before installing them to prevent premature wear. If replacing the spark plugs doesn’t work, have a professional take a closer look at the ignition system to find any issues.

2. The Engine Is Stuttering or Stalling

If your forklift will start but keeps stuttering or stalling during operation — and you’ve tried all the previous steps — a few things could be at play:

• Damaged fuel injector: Fuel injectors maintain the proper fuel-to-air ratio. If yours has clogged or broken, your engine won’t run smoothly until it’s cleared or replaced.
• Clogged air filters: Your engine needs adequate airflow to operate. Check that all air filters and their surrounding housings are clear. Don’t use forced air, as this could blow debris into more delicate parts of the engine. Your forklift’s operator manual or the filter packaging should tell you how long air filters are good for before they need to be replaced. If you’re installing a new one, write the installation date on the filter for future reference.
• Faulty alternator: If you’re also experiencing electrical malfunctions, like issues with the lights, your alternator needs a closer look. A professional can help you diagnose and address the issue. Keep your alternator in good shape by cleaning the area regularly to avoid buildup and testing the tension level of the connector belt as part of your routine maintenance.

3. You See Steam or Smoke

If your forklift is actively emitting steam or smoke, the first step is to move to a well-ventilated area before investigating. Wear protective equipment to protect your lungs and skin — these emissions can get very hot, especially if your forklift was operating for a while before they appeared. Give the machine time to cool down before you begin troubleshooting, and keep it away from open flames and combustible materials.

Once it’s safe to do so, visually inspect the area where the steam or smoke was coming from. Some possible causes include:

1. Oil leaks: Smoke accompanied by a strong burning smell could indicate an oil leak. Check that all seals and gaskets are functional and replace them as needed. Clean up any excess oil before you try starting the forklift again.
2. Hydraulic leaks: Inspect the hydraulic system’s hoses and fittings and ensure they’re tightly secured. Before operating the forklift again, replace any damaged or corroded parts. Confirm that all hydraulic levels are at their minimum and below their maximum thresholds.
3. Inadequate airflow: Clear or replace clogged air filters and clean the air intake system to promote airflow and prevent smoke emissions from backing up. Make sure the exhaust isn’t obstructed.

4. The Tires Are Bulging or Have Worn Tread

One of the most common forklift problems is tire quality. Without good tires, your machine won’t have adequate traction, balance or load bearing. Inspect each tire during routine maintenance and note any abnormalities. 

Tread below the wear line — which is generally at about the halfway mark for forklift tires — means it’s time to replace the tire. If your tread is wearing down unevenly, you likely have some alignment issues with your machine, or the suspension may need adjusting.

If your tire has a bubble or bulge on its sidewall or the tread, don’t use the forklift until you replace the tire. These are places where the tire’s inner air has moved too close to the surface, often after impact. In some cases, the tire’s layers may begin separating, leading to blowout or damaging other components.

Protect your tires against damage and premature wear with these tips:

• Avoid sudden acceleration or stopping while at full operating speed.
• Clear the work area of any sharp debris if possible.
• Ensure proper tire pressure and never operate the forklift when air pressure is above or below the recommended level.
• Keep brakes lubricated and in good operating condition. 

5. Operation Is Sluggish or Erratic

Shifting and steering problems are more than inconvenient — they’re dangerous for the forklift operator and people nearby. These often result from:

• Low steering fluid levels: Your forklift operator manual should have a list of recommended fluid levels for various components, including the steering system. Make sure you have enough steering fluid in the machine without exceeding the maximum amount. If you have enough fluid, but it has changed from liquid to a thick or sludgy consistency, empty it and replace it.
• Tire misalignment: When tires are off balance, they strain the forklift’s transmission system. They can also warp the axle, impacting how well the machine drives. Regular professional tune-ups are the best way to catch issues like these before they escalate.
• Worn or damaged gears: Sometimes, poor shifting is as simple as rusted, worn or damaged gears or steering wheels. While some components might be fixable, professional replacement is usually the best option.

Lifting and Lowering Problems

If your forklift mast is moving sluggishly or making jerking motions, it could be one of the following issues:

• Low hydraulic fluid levels: Adequate hydraulic fluid levels are essential for lifting and lowering loads. Fill your hydraulic fuel tank to the maximum fill line, and clean any buildup on the pump filters. If you keep running low, you might have a leak in the hose or cylinder.
• Overloading the machine: Each forklift has its own load capacity. Exceeding it can result in poor or slow lifting or even cause the forklift to tip, especially if the operator isn’t trained on the correct way to load the forks according to the object’s center of gravity. Minimize the risk of overloading by implementing regular operator training on best loading practices and displaying the machine’s maximum load capacity somewhere easily visible.
• Damaged wires or switches: The forklift’s mast relies on various wires and switches to operate. If one becomes loose, damaged or exposed, the machine will stop performing correctly.

6. Warning Lights Are On

Many modern forklifts are designed to make diagnosing problems easier with dashboard warning lights. Yours might signify one or several of the following:

• Engine temperature warning
• Oil pressure warning
• Low battery charge
• Check engine 
• Seatbelt reminder
• Load limit warning
• Service reminder
• Warnings for specific systems, like the hydraulics

The type of warning light gives you or a professional technician a starting point for troubleshooting and repair. If you’re not sure what a certain light means, consult your operator manual.

7. Operators Have Experienced Brake Failure

Brakes won’t work properly if they’re damaged or excessively worn. Your maintenance routine should include checking the brakes frequently and replacing rotors and brake pads as needed. Get more operating hours out of your brakes with these best practices:

• Don’t leave the parking brake engaged when it’s not needed.
• Avoid braking too quickly — always slow your speed first.
• Be mindful of where your foot is placed when driving. You don’t want to ride the brake pedal.
• When you apply the brakes, do so fully.
• Don’t continue operating a forklift if the brakes are malfunctioning, as this could worsen the problem or damage other parts of the machine.
• Make sure you’re using the correct brake fuel for your forklift.

8. Fluid Is Leaking

One of the easiest ways to locate the source of a leak is to park your forklift indoors so you can check the flooring around it the next day. Once you know what part of your machine the leak is coming from — such as the engine or radiator — you’re better prepared to troubleshoot. You should also inspect the fluid itself to identify whether it’s oil, fuel, hydraulic fluid or something else. 

Most leaks result from loose, disconnected, or damaged clamps, hoses, or O-rings. Check critical connections and individual component seals during your routine maintenance to prevent further leaks.

9. The Controls or Accessories Aren’t Working

Dashboard controls and safety accessories can stop working over time, especially if you operate or store your forklift outdoors. Check for signs of deterioration or corrosion, and don’t attempt to fix broken wires with electrical tape. If any contact points are caked with buildup, clean each one and replace them as necessary. If nothing seems out of the ordinary, you might have a blown fuse — a professional technician can help.

Clean and lubricate controls, electrical contacts and accessories often to reduce premature wear.

10. You Hear Unusual Sounds

While some level of noise is expected when operating heavy equipment, unusual sounds almost always signify a larger problem that needs attention. Listen closely — the type of sound you hear is the best way to identify the source. Here are some common examples:

• Grinding or scraping: These sounds usually mean metal is moving against other metal. Worn brake pads or damaged bearings could be the culprit.
• Hissing: When hydraulic systems leak, it sometimes makes a soft hissing or whistling sound as the pressure changes.
• Thumping or rattling: If you hear thumping or rattling while the forklift is in operation, an internal component like a bolt or nut has probably come loose. Tighten all connection points regularly as part of routine maintenance.
• Squealing or squeaking: Worn or unlubricated brake pads cause high-pitched squealing. Keep all components greased frequently. 
• Banging: Problems with the transmission or suspension system can cause loud banging sounds, especially when turning the forklift or when operating over uneven terrain. Make sure your professional tuneups include alignments.
• Clicking: Your forklift’s lift mechanisms may click if they need lubrication or realignment. 
• Rumbling: Low rumbling when starting the forklift could be related to the engine. Professional diagnosis is the best way to handle engine issues.

11. The Forks Are Unstable or Experiencing Excessive Load Sway

Your machine’s forks will wear down over time. As they do, their load capacity may lessen, leading to sagging or swaying when lifting, tilting or lowering loads. You can monitor these changes by establishing a baseline. Use calipers to measure the shaft and the thickness of various points along the fork, including the blade, heel and hook. Recheck these measurements at regular intervals and note changes. 

If the forks become too bent to function, don’t attempt to unbend them yourself. You’ll save a lot of time and frustration — and be a lot safer — if you replace them.

Note that newer forks that aren’t bent may still sway or sag if the blades aren’t installed at the same height.

Keep Your Forklift Operational With Bohl Equipment Co.

A preventive maintenance routine is the best way to avoid these pitfalls and prolong your equipment’s life span. The better you care for your forklift, the less downtime and fewer costly repairs you’ll experience. Keeping your forklift in optimal condition also helps you maintain a safer working environment. Your routine should include daily, weekly and monthly equipment inspections as well as professional servicing every couple hundred service hours.

If you’re having trouble with your forklift — or want to set up a professional maintenance plan to prevent these common issues — Bohl Equipment Co. can help. Our service departments in Ohio and Indiana are equipped to handle repairs for all makes and models on-site or at our facility.

We’ll also work with you to establish a customized fleet maintenance plan that includes periodic maintenance to keep your equipment in top shape. We can even help you find the right rental equipment to use in the meantime if your machine requires extensive repair.

Give us a call or contact us through our quick form to get started!