How to Change String in Dewalt Weed Eater? Fast Tutorial

Introduction

Dewalt weed eaters, also known as string trimmers, are a top choice for both residential and commercial landscapers thanks to their durable build, powerful motors, and long battery life (for cordless models) or reliable gas performance. But even the toughest Dewalt trimmer will underperform when its cutting string wears down from friction with rocks, dirt, and thick vegetation. Many users assume that replacing the string requires a trip to a repair shop or a costly replacement part, but learning how to change string in Dewalt weed eater is a simple, 10-minute DIY task that saves you time, money, and unnecessary downtime.

This fast, comprehensive tutorial covers every step of the process, from identifying the right trimmer line for your specific Dewalt model to troubleshooting common post-replacement issues. Whether you’re a first-time DIYer or a seasoned landscaper, this guide will help you get your trimmer back to peak performance in no time, no special tools or professional experience required.

• Introduction
• Understanding Your Dewalt Weed Eater Trimmer Line
• Common Trimmer Line Types for Dewalt
• Correct Line Size for Your Dewalt Model
• Tools and Materials You’ll Need
• Safety Precautions Before Starting
• Step-by-Step Guide: How to Change String in Dewalt Weed Eater
• Tips for Longer Trimmer Line Life
• Common Mistakes to Avoid When Changing Trimmer Line
• Comparing Dewalt Trimmer Line Options
• Troubleshooting Common Post-Replacement Issues
• Frequently Asked Questions
• Conclusion

Understanding Your Dewalt Weed Eater Trimmer Line

Before you start the replacement process, it’s helpful to understand the basics of Dewalt trimmer line, as using the wrong type or size is the most common cause of poor performance and frequent jams. Dewalt designs their weed eaters to work with a range of trimmer line options, but all models follow a consistent spool design that makes replacement straightforward once you know what to look for.

Most Dewalt weed eaters use a bump-feed or auto-feed system, where the line extends automatically when you tap the trimmer head on the ground while the tool is running. The line is stored on a removable spool inside the trimmer head housing, which you can access by removing a small plastic cover. The spool has notches that align with the housing to keep it in place, and small exit holes that the line threads through to feed out during use.

Common Trimmer Line Types for Dewalt

Dewalt recommends three main types of trimmer line for their weed eaters, each suited for different use cases:

• Round line: The most common and affordable option, round line has a smooth, circular cross-section. It’s ideal for general lawn maintenance, cutting grass and light, thin weeds. It produces low vibration and is easy to load, but it wears down faster than other types when cutting thick vegetation.
• Square line: With a square cross-section that has sharp edges, square line cuts through thicker, tougher weeds and overgrown grass more effectively than round line. It’s more durable and lasts longer, but it produces slightly more vibration during use.
• Twisted line: Made by twisting two strands of line together, twisted line is the most durable option available for Dewalt weed eaters. It resists fraying and breaking, produces very low vibration, and is ideal for heavy-duty, frequent use. It’s more expensive than round or square line, but its longer lifespan makes it cost-effective for commercial landscapers or users with large properties.

While Dewalt sells their own OEM trimmer line, high-quality aftermarket options from reputable brands work just as well, as long as they match the required diameter and type for your model.

Correct Line Size for Your Dewalt Model

Trimmer line is measured by its diameter, and using the wrong size is one of the most common causes of jams, poor cutting performance, and even motor damage. Most residential Dewalt weed eaters use 0.065-inch or 0.080-inch line, while heavy-duty commercial models use 0.095-inch line. Some smaller, compact Dewalt models may use 0.055-inch line for lighter use.

You can find the exact line size required for your model in three places: the owner’s manual that came with your trimmer, printed on the side of the existing spool, or on the Dewalt website by entering your model number. Using a line that’s too thick will overload the trimmer motor, causing it to overheat or burn out over time, while a line that’s too thin will break easily and won’t cut through thick weeds effectively. If you’re unsure which size to buy, err on the side of a slightly smaller diameter, as most Dewalt trimmer heads can accommodate a range of sizes within 0.005 inches of the recommended spec.

Tools and Materials You’ll Need

One of the best parts of changing your Dewalt weed eater string is that you don’t need any special, expensive tools to get the job done. Most of the items you’ll need are already lying around your garage or tool kit. Here’s a full list of what to gather before you start:

• Replacement trimmer line (correct diameter and type for your Dewalt model)
• Work gloves (to protect your hands from sharp line edges)
• Small flathead screwdriver or trimmer line removal tool (to pry off the trimmer head cover)
• Tape measure or ruler (to cut the line to the correct length)
• Heavy-duty scissors or line cutter (to cut the line cleanly)
• Clean, dry rag (to wipe debris out of the trimmer head housing)

If you don’t have a dedicated trimmer line removal tool, a small flathead screwdriver works perfectly for prying off the cover on most Dewalt models. Avoid using metal tools that could scratch or damage the plastic trimmer head housing.

Safety Precautions Before Starting

While changing trimmer line is a low-risk task, taking a few basic safety precautions will prevent injury and damage to your trimmer. Follow these steps before you touch any parts of the weed eater:

1. Disconnect all power sources: For cordless Dewalt models, remove the battery pack from the trimmer handle. For electric corded models, unplug the trimmer from the outlet. For gas-powered models, turn off the fuel valve to stop fuel flow to the engine. Even after disconnecting power, press the trigger a few times on cordless models to drain any residual charge from the motor.
2. Let hot engines cool: If you were using the trimmer recently, let the engine (for gas models) or motor housing (for electric/cordless models) cool for at least 15 minutes before touching it, as these parts can get hot enough to cause burns.
3. Wear protective gear: Put on work gloves to avoid cuts from sharp trimmer line edges. Avoid wearing loose clothing, jewelry, or long sleeves that could get caught in the trimmer head if it accidentally starts up.
4. Work in a well-ventilated area: If you’re cleaning debris out of the trimmer head, work outside or in a well-ventilated garage to avoid inhaling dust, grass clippings, or pollen.

Never attempt to change the trimmer line while the tool is connected to a power source or has a battery installed, as accidental startup can cause serious injury.

Step-by-Step Guide: How to Change String in Dewalt Weed Eater

This step-by-step process works for nearly all Dewalt weed eater models, including the 20V MAX, 40V MAX, and gas-powered XR series. Follow these instructions carefully to avoid jams and ensure your new line feeds correctly:

1. Prepare the trimmer for disassembly: Lay the weed eater on a flat, stable surface, such as a workbench or the ground. Turn the trimmer head upside down so the spool is facing up, making it easy to access. Double-check that the battery is removed (for cordless models) or the trimmer is unplugged (for electric models).
2. Remove the trimmer head cover: Most Dewalt models have a twist-lock plastic cover held in place by a small clip or threaded lock. If your model has a clip, press the release button on the side of the head to free the clip, then pull the cover straight off. If it has a threaded cover, twist it counterclockwise until it loosens, then remove it. Set the cover aside in a safe place where it won’t get lost.
3. Remove the old spool and clean the housing: Pull the old spool straight out of the trimmer head housing. If there’s any remaining old line on the spool, pull it off and discard it. Use your clean rag to wipe out any grass clippings, dirt, or debris from inside the housing, as leftover debris can cause the new spool to stick or the line to jam.
4. Prepare the new trimmer line: Cut the line to the recommended length for your model: 10-12 feet for 0.065″ line, 8-10 feet for 0.080″ line, or 6-8 feet for 0.095″ line. Use heavy-duty scissors or a line cutter for a clean, straight cut to prevent fraying. For dual-line models, cut two equal lengths of line.
5. Load the line onto the spool: Insert one end of the line into the anchor notch on the spool, then wrap the line around the spool in the direction of the arrow printed on the spool (almost always clockwise). Keep the line taut as you wrap, avoid overlapping layers, and leave 4-6 inches of line sticking out when done. Tuck the loose end into a small notch on the edge of the spool to hold it in place. Repeat this process for the second line if you’re using dual line.
6. Reinstall the spool in the trimmer head: Align the small notches on the sides of the spool with the slots inside the trimmer head housing. Push the spool in firmly until it clicks into place, making sure it’s seated evenly and doesn’t wobble. Thread the loose ends of the line through the small exit holes in the trimmer head cover, pulling them through until 4-6 inches of line extends out from the head on each side (for dual line) or one side (for single line).
7. Reattach the trimmer head cover: Line up the cover with the housing, making sure the line ends are threaded through the correct holes. If your model has a clip, snap the clip back into place until it clicks. If it has a threaded cover, twist it clockwise until it’s tight, but don’t over-tighten it, as this can crack the plastic cover. Tug gently on the line ends to make sure they’re locked in place and won’t pull out when you use the trimmer.
8. Test the trimmer: Reinstall the battery (for cordless models) or plug in the trimmer (for electric models). Turn the trimmer on and let it run for 10-15 seconds, tapping the head on the ground a few times to test the auto-feed function. Check that the line extends properly and doesn’t jam. If the line doesn’t extend, turn off the trimmer immediately, remove the cover, and adjust the line to make sure it’s seated correctly in the exit holes and spool.

If you follow these steps correctly, you’ll have a fully functional trimmer in minutes, ready to tackle overgrown grass and weeds around your property.

Tips for Longer Trimmer Line Life

Once you’ve mastered how to change string in Dewalt weed eater, you can extend the life of your new line and reduce how often you need to replace it with these simple tips:

• Avoid cutting hard surfaces: Never drag the trimmer head across concrete, gravel, rocks, or tree trunks while cutting, as this grinds down the line extremely quickly. Keep the head 1-2 inches above the ground while trimming to avoid unnecessary wear.
• Only cut appropriate vegetation: Trimmer line is designed for grass and light, thin weeds. Never use it to cut woody stems, thick brush, or saplings – use a brush cutter attachment or pruning shears for these tasks, as forcing the line through tough material will break it instantly.
• Store the trimmer properly: Keep your weed eater in a cool, dry place out of direct sunlight. Extreme heat and UV exposure make trimmer line brittle and prone to breaking, while damp storage can cause the line to warp or degrade.
• Use the correct line for your use case: If you only trim light grass once a week, round line is a cost-effective choice. If you have a large property or cut thick weeds regularly, invest in twisted or square line, which lasts 2-3 times longer than round line and reduces how often you need to replace it.
• Clean the trimmer head regularly: After each use, wipe out any grass clippings or debris from the trimmer head housing. Built-up debris can cause the spool to stick, leading to uneven line feed and increased wear on the line.

Common Mistakes to Avoid When Changing Trimmer Line

Even experienced DIYers make these common mistakes when replacing Dewalt trimmer line, which can lead to jams, poor performance, or even damage to your trimmer. Avoid these errors to make the process as smooth as possible:

• Using the wrong line size or type: As mentioned earlier, using line that’s too thick or too thin will cause poor performance and can damage your trimmer’s motor. Always check your owner’s manual for the recommended specs before buying replacement line.
• Wrapping the line in the wrong direction: The arrow on the spool indicates the correct winding direction. Wrapping the line counterclockwise (the opposite of the arrow) will cause it to tangle and jam as soon as you turn the trimmer on, as the auto-feed mechanism is designed to pull line off the spool in the clockwise direction.
• Overfilling the spool: Wrapping too much line onto the spool will cause it to bunch up, leading to jams and preventing the cover from fitting properly. Stick to the recommended line length for your model, and wrap the line neatly without overlapping.
• Forgetting to thread the line through the exit holes: If you don’t pull the loose ends of the line through the exit holes in the trimmer head cover, the line will get stuck inside the housing and won’t extend during use. Always double-check that the line is threaded correctly before reattaching the cover.
• Not disconnecting power before starting: This is the most dangerous mistake, as accidental startup can cause serious lacerations from the spinning line. Always remove the battery or unplug the trimmer before you start disassembling the head.
• Using low-quality aftermarket line: Cheap, no-name trimmer line breaks easily, frays quickly, and can leave small plastic shards inside the trimmer head that damage the motor. Stick to reputable brands or Dewalt OEM line for the best performance and longevity.

Comparing Dewalt Trimmer Line Options

Choosing the right trimmer line for your Dewalt weed eater depends on how often you use the tool and what type of vegetation you’re cutting. The table below compares the three most common Dewalt-compatible line types to help you make the best choice for your needs:

For most casual users who only trim their lawn once a week, round line is more than sufficient and the most cost-effective option. If you have a large property or regularly cut thick, overgrown weeds, square or twisted line will save you time and money in the long run by reducing how often you need to replace the line.

Troubleshooting Common Post-Replacement Issues

Even if you follow the step-by-step guide perfectly, you may run into small issues after replacing your trimmer line. Here are the most common problems and their quick fixes:

• Line won’t extend when I tap the head: First, check that the line is threaded through the exit holes in the trimmer head cover. If it is, remove the spool and make sure the line is wrapped in the correct direction and not tangled. If your model has an auto-feed adjustment knob, make sure it’s not set to “off”.
• Line breaks frequently after replacement: This is almost always caused by using the wrong line size, a damaged trimmer head with burrs that catch the line, or hitting hard surfaces while trimming. Inspect the trimmer head for sharp edges or damage, and make sure you’re using the correct line for your model.
• Trimmer vibrates excessively after replacement: Check that the spool is seated evenly in the housing and that the line is wrapped neatly without overlapping. Uneven line distribution on the spool is the most common cause of excess vibration. If the spool is damaged or cracked, replace it with a new OEM Dewalt spool.
• Line gets tangled inside the head: This happens when the line is wrapped in the wrong direction, overfilled on the spool, or the two ends of dual line are different lengths. Remove the spool, unwind the line, and reload it following the correct winding direction and length guidelines.

Frequently Asked Questions

How often should I change the string on my Dewalt weed eater?

There’s no fixed timeline for replacing your Dewalt weed eater string, as it depends on how often you use the trimmer and what type of vegetation you’re cutting. For light residential use (trimming grass 1-2 times per week), you’ll typically need to replace the line every 1-2 months. For heavy use (cutting thick weeds, overgrown areas, or commercial landscaping), you may need to replace it every 2-4 weeks. Check the line regularly for fraying, wear, or shortening, and replace it as soon as you notice a drop in cutting performance, rather than waiting for it to break completely during use.

Can I use aftermarket trimmer line in my Dewalt weed eater?

Yes, you can use high-quality aftermarket trimmer line in your Dewalt weed eater, as long as it matches the exact diameter and type recommended for your specific model. Avoid cheap, unbranded aftermarket line, as it often breaks easily, frays quickly, and can leave plastic shards inside the trimmer head that damage the motor. Always check your owner’s manual for the recommended line specs before purchasing aftermarket options, and stick to reputable brands with good customer reviews to ensure the best performance.

Why does my Dewalt weed eater string keep breaking?

Frequent string breakage is almost always caused by one of four issues: using the wrong line size or type for your model, hitting rocks, concrete, or woody stems while trimming, a damaged trimmer head with sharp burrs that catch and snap the line, or overfilling the spool so the line bunches up and jams. Inspect your trimmer head for damage, confirm you’re using the correct line, and avoid cutting hard surfaces to fix the problem.

Do I need to change the whole spool when the string wears out?

No, you only need to replace the trimmer line itself, not the entire spool. The spool is a reusable plastic component that will last for years as long as it’s not cracked, warped, or damaged. Simply remove the old line, clean the spool, and load new line onto it following the steps in this guide. You only need to replace the spool if it’s visibly damaged or no longer fits securely in the trimmer head housing.

What size string does my Dewalt weed eater use?

The required string size varies by model, but most residential Dewalt weed eaters use 0.065-inch or 0.080-inch round line, while heavy-duty commercial models use 0.095-inch square or twisted line. Smaller compact models may use 0.055-inch line for light, occasional use. You can find the exact size for your model in the owner’s manual, printed on the side of the existing spool, or on the Dewalt official website by entering your model number.

Conclusion

Learning how to change string in Dewalt weed eater is one of the easiest and most useful skills any Dewalt tool owner can learn. What might seem like a complicated repair at first is actually a simple, 10-minute task that requires no special tools or professional experience. By following the step-by-step guide in this tutorial, using the correct line for your model, and avoiding common mistakes, you can keep your trimmer running at peak performance all season long without spending extra money on repair shops or replacement parts.

Remember to always disconnect power before starting the replacement process, use the correct line size and type for your Dewalt model, and clean the trimmer head regularly to extend the life of both your line and your tool. With these tips, you’ll be able to tackle overgrown grass and weeds around your property quickly and efficiently, no matter what time of year it is.