[Lifetime Warranty] 537388101 T35 Trimmer Head - Compatible with Husqvarna 123L 225L 232L 322L 323L 324Lx 325L 326L 522L 525L 525LS - Replaces 531300183 (M10 x 1.25 LH) - Prewound with 0.095" Line | Pack of 2

537388101 T35 Trimmer Head

Key Features

• Precision Tap Advance Mechanism: Specifically engineered for commercial-grade durability, the T35 head allows for instant line advancement with a simple tap on the ground during operation.
• Split-Spool Internal Design: Features an integrated divider that keeps the two lines separate, preventing "overlapping" and line welding that can cause the head to jam.
• High-Impact Blue Bump Knob: The characteristic blue knob is manufactured from high-density, wear-resistant polymer to withstand thousands of impacts with asphalt and soil.
• Easy-Reload Interface: Designed with an open-eyelet system that allows for rapid line threading and winding without the need to turn the head upside down or use specialized tools.
• Prewound with .095" Line: Comes factory-loaded with premium 0.095-inch diameter titanium-style line, providing an aggressive cut for heavy weeds and thick grass right out of the box.

Replaces / Cross-Reference Part Numbers

• 537388101
• 531300183
• 531300194

Compatibility & Fitment

This "T35" series head is the standard professional choice for Husqvarna's straight-shaft trimmers. Key compatible models include:

• Husqvarna 100/200 Series: 123L, 123LD, 225L, 232L, 232R.
• Husqvarna 300 Series: 322L, 323L, 324Lx, 325L, 325Lx, 326L, 326Lx, 327LS.
• Husqvarna 500 Series: 522L, 525L, 525LS, 525LST, 535LS.
• Technical Specification: Fits all models with an M10 x 1.25 LHF (Left Hand Female) arbor thread.

When to Replace

• Worn-Through Bump Cap: The blue center knob has ground down to the point where the internal spring is visible or it no longer triggers the line release.
• Cracked Outer Shell: Visible stress fractures in the black housing, which can lead to the head shattering at high RPMs.
• Eyelet Failure: The metal line exits (eyelets) have fallen out or are deeply grooved, causing the trimmer line to snap off inside the head repeatedly.
• Internal Spool Jamming: The plastic "teeth" inside the head that lock the spool have rounded off, causing the head to dump all the line at once during use.
• Excessive Vibration: The head has become unbalanced due to uneven wear, putting unnecessary stress on the trimmer's gear head and drive shaft.

Installation Tips

• Left-Hand Threads: Remember, this head is Left-Hand Threaded. To tighten it onto the trimmer, you must turn it Counter-Clockwise.
• Lock the Gear Head: Use a small hex key or the factory locking pin to hold the gear head shaft stationary while you spin the old head off and the new one on.
• Spool Direction: When reloading line, follow the "LH" arrows molded into the spool. Loading the line in the "RH" direction will prevent the bump-feed mechanism from working.
• Soak Your Line: To extend the life of your trimmer line, soak the spool in water for 24 hours. This keeps the nylon hydrated, making it more flexible and resistant to snapping at the eyelet.
• Clean the Spring: Every time you reload the line, shake out any dirt or grass trapped around the internal spring to ensure the "bump" action stays smooth and responsive.