How to Reline a Weed Eater: Line Sizes, Spool Winding, and Field Fixes Posted by : admin / Posted on : Nov 20,2026

A trimmer head that keeps breaking line or refusing to feed usually has a simple cause: the spool was wound in the wrong direction, the line diameter is too large for the head, or the line was not seated under the retaining slot before the cover went back on. The good news is that relining a weed eater is a fifteen-minute job once you match the head type and line size. The reliable process is to disconnect power, remove the spool, clean the head, wind the line in the direction of the arrows, leave equal tails, and test the bump feed before you return to the fence line.

Match the line and head before you open the spool

The first decision is not how to wind the line but which line the head was designed to take. Most failures start with a line that is one size too thick, a spool that is overfilled, or a replacement line that is too stiff for the guide eyelets. Check the manual or the sticker on the head for the specified diameter. Common trimmer line sizes include 0.065, 0.080, 0.095 and 0.105 inch, but the correct choice is the one listed for your model, not the thickest line that fits through the eyelet.

• Standard bump-feed head: uses a spool and a spring-loaded cover. The line feeds when you tap the head on the ground at operating speed.
• Speed-load or quick-load head: often accepts a short length through an eyelet and winds itself as you rotate the head. The line path is usually marked with arrows.
• Fixed-line head: uses short line segments or molded plastic blades. It does not bump-feed, so do not try to wind a spool into it.
• Brush cutter head: may use a metal blade or a heavier line head. Confirm the guard and harness are correct before changing the cutting attachment.

A second check is spool condition. Cracked spools, worn eyelets and missing springs cause line to snag or feed unevenly. If the cover does not seat with light pressure, stop and inspect the spool alignment rather than forcing it. For general handling and maintenance points, the lawn trimmer use guide is a useful reference before you start a repair.

A40DC350B01 40V Cordless String TrimmerA 40V cordless trimmer with 14-inch cutting width, bump-head line feed and dual twist line, useful when checking spool condition before repair.View Product →

Step-by-step reline for a standard bump-feed head

The sequence below covers the most common two-line spool. Some heads use two separate line lengths; others use one long line folded at the midpoint. The winding direction and the retaining slot matter more than the exact number of wraps.

Prepare the trimmer

Switch off the engine or remove the battery pack. On a gasoline trimmer, pull the spark plug boot off the plug and tuck it away from the cylinder. Wait for the head and muffler to cool. Wear gloves and eye protection, and work on a clean surface so small springs and washers do not disappear into grass clippings.

Remove and clean the spool

Press the release tabs or unscrew the retaining cap. Many threaded caps loosen clockwise, but check the cap or housing for an arrow before applying force. Lift out the spool, remove old line, and brush out dirt, dried sap and trimmed grass. Inspect the eyelets for sharp edges; a burr will cut new line within minutes.

Wind the line in the arrow direction

1. Cut two equal lengths of line, usually about 7 to 10 feet each for a two-line head, unless the manual states a different length.
2. Align the spool arrows with the eyelets in the head. Insert one line end into the spool anchor hole or slot, then wind it firmly in the arrow direction. Repeat for the second line on the other spool channel.
3. Keep light tension as you wind. Do not stretch the line or fill above the spool flange; an overfilled spool binds against the cover and stops feeding.
4. Leave about 6 inches of tail on each side. Feed each tail through its guide eyelet before pressing the spool fully into the head.
5. Fit the spring and cover, confirm the tabs click or the cap threads seat fully, then pull the tails to release them from the temporary holding slot.

Reassemble and test

Start the trimmer away from windows, pets and loose gravel. Bump the head lightly on grass or bare soil at low throttle. The line should advance in short, even increments. If it does not feed, stop the engine or remove the battery before opening the head again. Compact cordless models follow the same sequence; a 20V trimmer such as the H20DC250 may use lighter line and a smaller spool, so confirm the rated diameter before winding.

H20DC250/H20DC250X 20V Cordless String TrimmerA compact 20V cordless trimmer with 10-inch cutting width and 1.6 mm line, relevant when confirming spool and line size for lighter models.View Product →

Speed-load and fixed-line heads need a different approach

Do not assume every trimmer head is a standard spool. A speed-load head often uses a short line inserted through one eyelet until it exits the opposite side, then the head is rotated to take up the slack. A fixed-line head may use pre-cut segments with molded ends, and some models use plastic blades for heavier weeds. Using the wrong line or trying to overfill a quick-load head can damage the retaining mechanism.

• For a speed-load head, follow the arrows on the housing and pull equal lengths after the line passes through both eyelets.
• For a fixed-line head, use only the specified segment length; longer line can hit the guard or strike the housing.
• For a brush cutter with a blade, remove the line head and fit the correct guard, handlebar grip and harness before operation.

Troubleshooting reline problems in the field

Most feed faults can be diagnosed without opening the gearbox. Use the table below as a quick field check, then confirm the line diameter and winding direction against the manual.

Field checks that prevent repeat failures

A clean reline is only half the job. The other half is keeping the head and line in condition between jobs.

• Keep spare line sealed from dust and sunlight; brittle line breaks at the eyelet and feeds poorly.
• Do not trim against walls, fence posts or concrete. Impact damage wears the spool and guide eyelets.
• Clean the head after wet or dusty work. Caked soil changes spring tension and causes uneven feeding.
• Replace worn spools and covers rather than adding extra line to compensate for poor retention.
• For gasoline trimmers, check the spark plug boot and fuel before blaming the line feed; for cordless models, confirm the battery is charged and the contact pins are clean.

What dealers and landscape fleets should standardize

For a dealer, municipality or landscape contractor, the cost of a trimmer is not only the purchase price. It is also the time spent matching line, replacing spools and training operators. Standardizing a small number of line diameters and head types across a fleet reduces inventory and makes relining predictable. Before ordering a batch, check that replacement spools, covers and springs are available for the exact model, and confirm whether the head uses a bump-feed spool or a quick-load system.

Aosheng’s range includes gasoline brush cutters and 20V and 40V lithium trimmers, so buyers can compare platforms against the work profile rather than mixing incompatible heads. If you are specifying trimmers for a dealer program or a maintenance fleet, the contact page can confirm model details, spool availability and line specifications before you commit to an order.