How to Put Wire on Weed Wacker | Reline in 7 Steps

Replacing trimmer line looks harder than it is. The job comes down to one thing: matching your trimmer head type and following the directional arrow molded into the spool. Most line-feeding problems trace back to line wound the wrong way or a spool seated incorrectly. Here’s the full process, from pulling power to testing the feed, with the common mistakes that send people back to the store.

Find Your Trimmer Head Type First

String trimmers use three main head designs, and the reline method differs for each. Bump-feed heads let you tap the head on the ground to advance line. Fixed-line heads require manually repositioning the line when it wears short. Automatic-feed heads advance line continuously as the engine runs.

Your owner’s manual names the head type and gives the exact line diameter and length for your model. That spec matters more than anything else — a 0.095-inch line will not fit a head built for 0.065-inch line, and vice versa. When the manual says to cut 24-inch (61 cm) pieces, that measurement is specific to that trimmer, not a universal rule.

Step-by-Step: How to Reline a Weed Wacker

These steps cover the standard spool-loading procedure used across most bump-feed and automatic heads. Check your manual before starting, since cap removal varies by model.

1. Disconnect power completely. Remove the battery pack on cordless models or unplug the cord on electric trimmers. Never skip this — the head can spin if the trigger is bumped.
2. Remove the cap or bump knob. Press the release tabs on the sides of the head, or turn the cap counterclockwise, depending on your model. Set the hardware aside where it won’t roll away.
3. Take out the old spool and remaining line. If the line is jammed, cut it free with scissors rather than yanking. Clean debris and grass clippings from the housing and spool while you’re in there — a dirty spool assembly is a common cause of poor feeding.
4. Cut the new line to the length in your manual. Many models call for roughly 24-inch (61 cm) pieces, but confirm yours. Fold the line and insert the bend into the slot or anchor point on the spool.
5. Wind the line in the direction of the arrow. This is the step people get wrong. The arrow molded into the spool shows the winding direction, and it matters — wound the wrong way, the head will not advance the line correctly. Wind tightly, keeping even tension, and leave short tails free for threading.
6. Thread the tails through the eyelets. Align the spool’s notches with the head eyelets before seating it. On dual-line heads, keep both strands even so feeding stays balanced.
7. Reinstall the cap and test. Tug gently on the line to confirm it seats securely, then run the trimmer briefly so the line advances. If the line extends past the guard, trim it to length before use.

Common Mistakes That Ruin a Reline Job

Most trimmer problems after a reline trace to four fixable errors. Skipping the power disconnect tops the safety list. Using the wrong line diameter or a mismatched replacement spool causes jamming and poor cutting. Winding against the spool arrow stops the feed entirely. And leaving the line over-length lets it slap the guard and wear down fast.

One more: reinstalling a dirty spool. Grass packed into the housing creates friction that prevents smooth feeding, so wipe the area clean while the head is open. If your head uses pre-wound replacement spools instead of bulk line, the same cleaning rule applies — just swap the whole spool and thread the pre-set tails through the eyelets.

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When to Replace the Whole Head Instead

Sometimes the head itself is the problem, not the line. If the bump knob no longer advances line even with a correctly wound spool, or the head wobbles after reassembly, the internal spring or ratchet may have worn out. Replacement heads are inexpensive and install in minutes — check whether yours accepts a universal head or requires a brand-specific part.

Before buying anything, confirm whether your trimmer uses pre-wound replacement spools. If it does, skip the winding entirely and just drop in a fresh spool. The loading steps stay the same: align the notches, thread the tails, and test the feed.