How to Restring a Weed Eater the Easy Way at Home
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To answer the question of how do you restring a weed eater, first switch the tool off and unplug it or remove the battery, then take the spool out of the trimmer head, wind new line onto it in the direction the marks on the spool show, and reinstall it with the line ends routed through the correct exit slots. The exact steps depend on the feed system your trimmer uses, so check whether it has a bump-feed spool, an auto-feed spool or fixed-length pre-cut line inserts before you begin. This guide explains how to tell which one you have and walks through the general process for each.
Quick answer
- Disconnect power first: unplug a corded tool or remove the battery from a cordless one.
- Identify the head type. Bump-feed heads use a wound spool, auto-feed heads cut line to length as it advances, and fixed-line heads take pre-cut inserts.
- Wind or insert new line only in the direction and slots the head or manual shows.
- Test the head by bumping it on the ground with the tool off, then start the motor at low speed before trimming.
Know your head type before you open it
Most homeowner trimmers use one of three arrangements, and each needs a slightly different approach. Reading the label on the head and checking the manual takes a few minutes and prevents most restringing mistakes.
Bump-feed spools. The line is wound on a reel that sits inside the head. When the line wears down or breaks, you tap the head on the ground while the motor runs, and a release mechanism lets a fresh length of line feed out. Restringing means replacing the spool with one that is already wound, or winding new line onto the existing spool. This is the most common type on basic trimmers.
Auto-feed spools. These heads use a small cutter that keeps the exposed line at a practical length. The line advances as needed when the head is bumped or when the feed mechanism senses that more is needed. Auto-feed spools are still loaded with a wound line, so the replacement process resembles bump-feed winding, but the cutter position and exit slots matter more.
Fixed-line heads. These take pre-cut lengths of line inserted into slots in the head rather than a wound spool. The user threads the pre-cut pieces through the slots, which avoids winding altogether. Fixed-line heads are generally easier to load, although the line pieces wear out sooner than a long spool would.
Which line should you buy
Trimmer line comes in a few shapes and diameters. Round nylon line is the general-purpose choice and is suited to grass and light weeds. Star-shaped or extruded line has more cutting edges and is meant for tougher growth. Check the diameter and type printed on the existing spool or the head label, and match the replacement to what the manufacturer lists for your model. A line that is too thick can overload the motor and a line that is too thin wears out quickly, so the manual’s recommendation is the best guide.
Some trimmer kits in the pack include a spare spool, which is useful to keep on hand. For example, the BLACK+DECKER BESTA510 listing states that its included components are a string trimmer, an AF-100 spool, an auxiliary handle and a guard. The BESTA510 listing does not state the line diameter, so check the spool or manual on your own unit before buying line.
Spools for the BLACK+DECKER MTC220 combo are listed as AF-100 in the included components as well, and the listing does not state the line gauge. The same caution applies to every model: read the spool and manual rather than assuming a size.
General steps to restring a bump-feed head
Work on a flat, clean surface where you will not lose small parts. Keep the trimmer pointed away from people and pets while you work.
First, remove the spool cover. Most covers either twist off or are held by tabs and a small cap. Keep the spring and any washers in order, because the spring tension and washer positions are part of how the head works.
Second, remove the old spool and take off whatever remains of the old line. Clean out debris, grass and dirt from the spool housing with a dry cloth or a small brush. Packed grass can stop the spool from turning freely and can make the feed unreliable.
Third, cut a length of new line. Many manuals suggest a length in the range that the spool’s marking indicates. Cut the line so both ends are even. Then find the arrow or mark on the spool that shows the winding direction.
Fourth, wind the line onto the spool in the direction the arrow shows. Keep the line tight and even as you wind so it does not cross over itself. Leave the two ends sticking out and seat them in the spool’s notches or exit slots, following the diagram on the spool or head.
Fifth, reinstall the spool, the spring and the cover. Make sure the spool sits flat and the cover clicks or locks into place. A cover that is not seated can let the spool come loose during use.
Sixth, test the head. With the tool unplugged or the battery out, check that the spool turns and the line can move in the head. Then reconnect power, hold the trimmer with a firm grip and bump the head lightly on the ground. The line should release a short length. Start the motor at low speed and check the cut before you work at full speed.
General steps for an auto-feed head
Auto-feed heads follow the same first and last steps: power off, clean the housing, wind and test. The difference is the cutter and exit slots. When you seat the line, pass each end through the slot shown on the head so the line sits against the cutter. If the line does not sit against the cutter, the head may not feed correctly, and it can jam or fail to release line when you bump it. Consult the manual or the label on the head for the exact slot names and layout, because these vary between brands.
General steps for a fixed-line head
Fixed-line heads are usually the simplest to restring. Remove the cover, take out the old pieces, and insert new pre-cut lengths into each slot until they seat. Use the number of pieces the manufacturer shows for your head, because a wrong count can unbalance the head and cause vibration. Replace the cover and test the head as described above.
Mistakes that cause most restringing problems
- Winding in the wrong direction. The line may unwind when the head turns, or the feed may fail to release.
- Leaving the ends too short or too long. Very short ends can slip out, and very long ends can tangle or hit the guard.
- Forgetting to disconnect power. A tool that starts while you have a hand near the head can cause a serious cut or injury.
- Reinstalling the cover loosely. A loose cover can let the spool or spring work free during use.
- Running the trimmer with a damaged head. Cracks in the housing or a bent shaft should be checked before the tool is used again.
Safety while you work and while you cut
A trimmer head turns at high speed, and it can throw debris. Wear eye protection, such as safety glasses or a visor, every time you run the tool, and keep bystanders and pets well back. Debris from a trimmer can damage cars, windows and other nearby objects. Keep the head’s safety shield on the side facing you, and do not remove the guard.
When the tool is off, handle the cutting head carefully, because the line ends and any metal parts can be sharp. If you are unsure about a repair, or if the tool is damaged, stop and check the manual or contact the manufacturer rather than forcing parts into place.
FAQ
Do I need to remove the spool to restring a weed eater?
In most bump-feed heads, yes. You need the spool out of the housing so you can wind new line onto it evenly and seat it correctly. Fixed-line heads usually let you insert new pieces without removing the whole spool assembly, but check the head design first.
How do I know which way to wind the line?
Look for an arrow or a printed direction on the spool or head. Wind the line in the direction the arrow shows. If the spool has no marking, the manual should state the direction. Winding against the marked direction is a common cause of feed problems.
What line should I use?
Use the line type and diameter that the manufacturer lists for your model. Round nylon is a general-purpose choice. Star-shaped or extruded line is meant for tougher cutting. A listing that does not state the diameter means you should check the spool or manual on your own trimmer.
Why does my trimmer not feed line when I bump it?
The most common causes are line wound in the wrong direction, line ends not seated in the exit slots, a spool that is packed with grass, or a spring or cover that is not reinstalled correctly. Check each of these before assuming the head is damaged.
Is it safe to restring a weed eater myself?
For most homeowner trimmers, restringing is a routine task. Disconnect power first, follow the manual, and wear eye protection when you test the tool. If the housing is cracked or the head is damaged, have the tool checked instead of attempting a repair.
Can I use a metal blade in place of line?
That depends on the head and the manufacturer. Some trimmers allow blade attachments and others do not. Check the manual before fitting any blade, because a head that is not rated for a blade can fail or cause injury.
Bottom line
If your trimmer uses a bump-feed spool, wind new line in the marked direction, seat the ends correctly and test the head before you cut. If it uses an auto-feed spool, pay closer attention to the cutter and exit slots. If it uses fixed-line inserts, use the count the manufacturer shows. In every case, disconnect power first and wear eye protection.
For more on this tool category, see Top 10 Battery Powered Weed Eaters: 6 Real Picks Compared and Best Black and Decker 20V Cordless Weed Eaters.
