Trimmer Head Bump Knob

This knob is designed to replace part number 537338701 and is compatible with a wide range of models from brands including Husqvarna, Craftsman, Poulan, and Weed Eater. Before purchasing, verify that your current trimmer head uses this specific part number or a compatible bump feed system.

Installation is straightforward and typically requires no special tools. You generally just need to unscrew the old, worn-out knob and thread the new one into place, ensuring it is secure before operating the trimmer.

The bump knob is designed to be the sacrificial part of the trimmer head. Using durable, impact-resistant hard plastic allows it to absorb the shock of hitting the ground during the bump-feed process without damaging the internal components or the trimmer shaft.

This package includes two replacement bump knobs only. It does not include the internal spring or other spool components, so be sure to retain your original spring when replacing the knob.

These knobs are designed to restore the bump-feed functionality if the issue is limited to a worn or broken knob. If the internal spool housing or the trimmer head itself is cracked or stripped, replacing just the knob may not resolve the issue.