537185801 Bump Knob - Fits Husqvarna T35 Trimmer Head (2003-05, 2005-01, 2007-04) - 4 Pack
SKU: 32455411855

537185801 Bump Knob - Fits Husqvarna T35 Trimmer Head (2003-05, 2005-01, 2007-04) - 4 Pack

Sale price$13.53 Regular price$15.03
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Description

537185801 Bump Knob - Fits Husqvarna T35 Trimmer Head (2003-05, 2005-01, 2007-04) - 4 Pack537185801 Bump Knob Replacement Key Features High Impact Blue Polymer: Manufactured from a high density, abrasion resistant plastic specifically designed to withstand thousands of high velocity "bumps" against asphalt, gravel, and packed soil. Reinforced Structural Ribbing: The internal geometry features reinforced walls to prevent the knob from cracking or shattering under the extreme centrifugal force of commercial grade trimmers. Precision Spring

537185801 Bump Knob Replacement

Key Features

  • High-Impact Blue Polymer: Manufactured from a high-density, abrasion-resistant plastic specifically designed to withstand thousands of high-velocity "bumps" against asphalt, gravel, and packed soil.
  • Reinforced Structural Ribbing: The internal geometry features reinforced walls to prevent the knob from cracking or shattering under the extreme centrifugal force of commercial-grade trimmers.
  • Precision Spring Seating: Engineered with a centered internal recess to perfectly secure the T35's heavy-duty spring, ensuring a consistent and responsive line-advancement "snap" every time.
  • Commercial-Grade Multi-Pack: This 4-piece kit provides a cost-effective solution for landscaping fleets and large residential properties, ensuring you always have a spare on hand to prevent downtime.
  • Snap-In Tool-Free Installation: Designed as a direct-fit replacement that clicks into the existing T35 housing by hand, allowing for rapid field repairs without the need for specialized tools.

Replaces / Cross-Reference Part Numbers

  • 537185801

Compatibility & Fitment

This bump knob is the standard replacement for the professional "T35" series trimmer heads. 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.
  • Historical Production Dates: Compatible with T35 heads manufactured during the 2003-05, 2005-01, and 2007-04 production cycles.
  • Note: Specifically for the T35 head. If you have the smaller T25 or larger T45, this knob will not fit correctly.

When to Replace

  • Worn-Through Bottom: The center of the blue knob has ground down from pavement contact to the point where the internal metal spring is visible or falling out.
  • Broken Retaining Tabs: The plastic clips that lock the knob into the housing have snapped, causing the knob to fly off while the trimmer is spinning at high RPM.
  • Seized Mechanism: Significant buildup of dried sap, dirt, and debris has fused the knob to the internal spool, preventing it from releasing new line.
  • Rounded Indexing Teeth: The internal plastic "teeth" that click against the spool have rounded off, causing the head to dump all the line at once during use.
  • Visible Stress Fractures: White lines or cracks appearing in the blue plastic, indicating the material has become brittle and is prone to catastrophic failure.

Installation Tips

  • Clean the Housing: Before installing the new knob, use a stiff brush or screwdriver to remove all dried grass and mud from the locking slots and spring area to ensure a 100% secure lock.
  • Inspect the Spring: Ensure the internal metal spring is not rusted or collapsed. If the spring is weak, the new knob will stay "compressed," causing the line to feed uncontrollably.
  • Snap-Lock Check: Press the new knob firmly into the housing until you hear a distinct "click" on both sides. Give the knob a firm tug by hand to verify it is fully seated before starting the engine.
  • Manual Feed Test: With the engine off, press the knob in and pull the trimmer line manually to ensure the indexing mechanism is releasing the line smoothly.
  • Avoid "Riding" the Head: To maximize the life of your new knobs, try to avoid letting the trimmer head drag on the ground while trimming; only make contact with the surface when you need to advance the line.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 32455411855

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ReadingWriteNow
Los Angeles, US
★★★★★ 5
They work very well.
Number of Items: 2
I love these. I use them to wrap my tumbler before sublimating them in my sublimation oven. They work every well to let me see the process so I don’t scorch my design.
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Reviewed in the United States on October 16, 2025
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The Two Hsus
Alexandria, US
★★★★★ 5
Best out of all other heat tapes!
Number of Items: 6
It is extremely weird how excited I became when trying this tape out for the first time. I can't speak for all of the blue heat tapes but this one in particular is all sorts of great to use. Thicker, easier to tear, stronger adhesive than the brown and clear heat tapes I've tried. I started with the clear because I was afraid of the other colored tapes leaving marks on my substrates. The clear tape was a good amount of thickness and easy to tear and use but the adhesion was terrible. I would wrap it around the rim of tumblers, fold it down into the inside of the tumbler and it would pop right back up. Forget using it on any fabrics, did not hold sublimation sheets down to totes, shirts, mousepads, at all. The brown tape I used had better adhesion but was thin and stretchy? floppy? Didn't know this was even an annoying thing until I moved on to this blue tape and was just blown away. Still blows me away how it was cheaper than the other two kind but is the thickest and best gripping of them all. So far it does not leave any marks on any of my items. I'm so impressed by this tape that I still NOTICE it everytime it's tearing off perfectly or holding my things together so well.
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Reviewed in the United States on August 9, 2023
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Donna
Lowell, US
★★★★★ 5
great for sublimation for shirts, tumblers and also fast delivery
Number of Items: 4
This tape works great for my sublimation tumblers and shirts; there is no glue residue that is left behind. It gives my tumblers a good seal at the top and bottom and down the side where I don't have air gaps in my picture I want to sublimate on the tumbler. It is durable, and it does not smell. It is easy to use and cut. It is a great value for the money and it was delivered the next day.
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Reviewed in the United States on October 10, 2025
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jennifer newcomer
Boise, US
★★★★★ 5
A must have
Number of Items: 2
This tape is perfect! I’ve been using other types and nothing compares to blue tape. It holds well and is nice and wide. I’ve had no problems with it. Price is right as well.
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Reviewed in the United States on February 19, 2026
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Tc101899
Fort Morgan, US
★★★★★ 5
Works great I would recommend this
Number of Items: 4
Works perfect in my heat press
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Reviewed in the United States on April 9, 2026

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