How to Change Your Stihl Trimmer Head
Changing a Stihl trimmer head is a straightforward process essential for maintaining your strimmer's functionality. Whether you are replacing a worn-out head or fitting a different type, understanding the basic steps ensures you can perform this task efficiently. Generally, it involves securing the spool or the shaft, then unscrewing the old head or releasing its locking mechanism.
- Secure the trimmer head to prevent rotation during removal.
- Identify the correct tool or method for your specific Stihl model.
- Ensure the replacement head is compatible with your Stihl trimmer.
- Reassemble carefully, checking for secure fastening.
Many Stihl strimmer models utilise a specific tool or a simple locking pin system to facilitate head removal. The exact procedure can vary slightly depending on whether you have a tap-and-go head, a bump feed head, or a fixed-line head, and the specific model series your trimmer belongs to. Always consult your Stihl owner's manual for the most precise instructions tailored to your machine, as forcing components can lead to damage.
The primary objective is to lock the drive shaft or the spool so that when you apply rotational force to the head's retaining nut, the head unscrews or detaches without spinning the entire shaft. This prevents damage to the gearbox and ensures a clean removal. Once the old head is off, cleaning the threads or mounting area before fitting the new one is a good practice.
The correct method of securing the trimmer shaft is critical for a safe and effective head change.
Securing the Trimmer Head or Shaft
Most Stihl trimmers provide a mechanism to prevent the shaft from rotating. For models with a spool or a button release, you might insert a pin or a specific tool into a hole on the gearbox housing, directly above the cutting head. This pin engages with a notch or a hole in the spool or drive shaft, effectively locking it in place. For other models, particularly those with a more direct drive, the tool might simply brace against the gearbox casing to provide leverage.
Once the shaft is secured, you will typically need a wrench, often a specific Stihl tool or a standard socket wrench, to turn the retaining nut counter-clockwise. This nut holds the cutting head onto the shaft. If the nut feels exceptionally tight, a brief, sharp tap with a rubber mallet on the wrench handle can sometimes help loosen it, but always proceed with caution to avoid damaging the gearbox or the nut itself.
Choosing the Right Replacement Head
When you need to replace your Stihl trimmer head, compatibility is paramount. Stihl offers various cutting heads designed for different tasks and user preferences. Common types include:
- Tap-and-Go (AutoCut) Heads: These are the most prevalent, allowing you to advance the cutting line by tapping the head on the ground. They are versatile for general trimming and edging.
- Bump Feed Heads: Similar to tap-and-go, but the line is advanced by bumping the head against a surface.
- Fixed-Line Heads: These heads use pre-cut lengths of line that are manually inserted. They can be more durable for tougher tasks.
- Brushcutter Blades/Hedge Trimmer Attachments: While not strictly 'trimmer heads', these are alternative cutting attachments that fit some Stihl models.
Ensure the replacement head is listed as compatible with your specific Stihl model number. The connection type and thread size must match. Buying a head from a reputable dealer or directly from Stihl can help guarantee correct fitment.
Ensure your replacement head is compatible with your specific Stihl model number.
When to Consider Replacing Your Stihl Trimmer Head
Why would you need to change your Stihl trimmer head? The most common reason is wear and tear. Over time, the plastic components of a trimmer head, especially the spool housing and line feed mechanism, can become brittle, crack, or break due to constant vibration, impact with hard objects, and exposure to the elements. If your head is damaged, it might not feed line correctly, or it could even detach during operation, posing a safety risk.
Another key indicator that it's time for a replacement head for your Stihl trimmer is persistent issues with line feeding. If you find yourself constantly stopping to manually pull out the line, or if the tap-and-go mechanism is no longer advancing the line reliably, the internal parts of the head are likely worn out. This inefficiency not only wastes your time but also impacts the trimmer's cutting performance.
Beyond simple wear, you might also consider changing your Stihl trimmer head to adapt to different tasks. For instance, if you primarily tackle dense weeds or light brush, you might switch from a standard tap-and-go head to a more robust fixed-line head or even a brushcutter blade attachment if your Stihl model supports it. Conversely, if you only need to tidy up lawns, a finer line capacity head might be preferable.
The decision to replace a Stihl trimmer head often stems from necessity due to wear, but it can also be a strategic choice to enhance versatility.
Finally, consider damage from impacts. Hitting fences, rocks, or concrete can cause significant damage to the trimmer head, even if it's not immediately obvious. Cracks can propagate over time, leading to failure. Inspecting your trimmer head regularly for any signs of stress, cracks, or deformation is a proactive way to prevent unexpected breakdowns and ensure you are always prepared to continue your garden maintenance.
Inspect the gearbox where the trimmer head attaches after removal. Clean any debris and check for signs of wear or damage before fitting a new head.
Regular inspection helps identify potential issues before they lead to operational failure.
Alternatives to the Standard Stihl Trimmer Head
While Stihl's own range of AutoCut and TrimCut heads are reliable and designed for their machines, the aftermarket offers alternatives that some users find beneficial. When looking for replacement heads for Stihl trimmers, you're not limited to the exact OEM part if compatibility is confirmed. Exploring these options can offer different features or potentially more durable designs.
One popular alternative is the SpeedLoad head, which allows for very quick line reloading without needing to disassemble the entire head. You simply feed the line into designated ports and twist. This can be a significant time-saver if you frequently run out of line or switch line types. Many universal-fit heads are designed to work with a wide range of Stihl models, provided the thread size and shaft type match. It's crucial to verify these specifications; a mismatched head can cause damage to the trimmer's gearbox.
Another consideration is durability. Some aftermarket heads are constructed from heavier-duty plastics or even metal components, aiming for a longer lifespan than standard plastic heads, especially in demanding conditions. These might be better suited for users who frequently encounter tough vegetation or work in abrasive environments. However, heavier heads can sometimes add slightly more weight to the trimmer and may require a more powerful engine to operate optimally.
Investigate aftermarket heads for features like faster line loading or enhanced durability.
When evaluating alternative heads, compare their line capacity, the type of line they accept (e.g., round, square, twisted), and the ease of installation. Some heads might offer greater flexibility in line thickness or shape, which can improve cutting efficiency for specific types of growth. For example, a thicker, more robust line might be better for cutting through thick grass or weeds, while a thinner line might be more suitable for precise edging.
It's also worth noting that some users opt for specialized heads, such as those designed for specific line types like high-performance braided line, or heads that integrate features for easier line winding and management. Always check reviews and manufacturer specifications for third-party heads to ensure they are a good fit for your Stihl trimmer and your typical workload.
If you frequently use thicker line for tough jobs, look for replacement heads that explicitly state compatibility with larger diameter line, often 2.4mm or higher.
Fitting a New Stihl Trimmer Head
Once you have the correct replacement head for your Stihl trimmer, fitting it is the reverse of removal. Ensure the shaft is still secured using the appropriate tool or pin. Take your new head and align it with the threaded shaft or mounting point on the gearbox. Screw the new head on clockwise by hand first, feeling for the threads to engage smoothly.
If the new head is a screw-on type, you'll then use your wrench to tighten it. Again, ensure the shaft is locked to prevent rotation. Tighten it firmly, but avoid overtightening, which can strip the threads or damage the gearbox. If your model uses a bolt or a nut system, follow the specific tightening procedure outlined in your manual or the instructions provided with the new head.
After the head is securely fitted, remove the locking pin or tool from the gearbox. It's good practice to give the new head a gentle wiggle to ensure it's completely secure. Then, load the appropriate trimmer line according to the instructions for your specific head model. For tap-and-go or bump feed heads, this usually involves feeding the line through the eyelets and winding it onto the spool, ensuring the lines are wound in the correct direction and are even.
Always check that the trimmer line is wound evenly and correctly for optimal performance.
Before starting actual trimming, test the new head. With the engine running at a low to medium speed, gently tap the head on the ground to advance the line (if it's a tap-and-go model). Verify that the line feeds out smoothly and to the correct length. If it doesn't feed, recheck the line winding and the head's locking mechanism. Some heads have specific tension settings or require the line to be fed through specific channels.
If you encounter any difficulties during the fitting process, or if the new head does not seem to operate correctly after installation, it's always best to refer back to your Stihl owner's manual or seek assistance from an authorised Stihl dealer. Incorrect installation can lead to poor performance, reduced efficiency, or even damage to your equipment.
Maintaining Your Stihl Trimmer Head for Longevity
To ensure your Stihl trimmer head, whether original or an alternative, lasts as long as possible, a few simple maintenance practices are recommended. The most crucial aspect is keeping it clean. After each use, particularly if you've been working in damp or dusty conditions, remove any grass clippings, dirt, or debris from around the head and spool. This prevents material from hardening and impeding the line feed mechanism.
Regularly inspect the trimmer line itself. Ensure it's not frayed, kinked, or tangled within the spool. If the line becomes brittle or degraded from UV exposure or age, it's more prone to breaking during operation, leading to frustration and reduced cutting effectiveness. Replace the line when it shows signs of wear or when you notice a decrease in cutting performance.
For tap-and-go or bump feed heads, pay attention to the condition of the eyelets through which the trimmer line passes. These plastic or metal inserts can wear down over time. If they become enlarged or damaged, the line can cut unevenly or snag, reducing efficiency. Some models allow for replacement of these eyelets.
Cleaning debris regularly prevents material from hindering the line feed mechanism.
When storing your strimmer, especially for extended periods, it's advisable to remove the trimmer head. Clean it thoroughly, and consider storing the head separately, perhaps with a small amount of line wound onto it, to make the next change easier. Ensure it's stored in a dry place, away from direct sunlight, which can degrade plastic components over time. Applying a silicone-based lubricant sparingly to the internal moving parts of the head can also help maintain smooth operation and prevent seizing, though check your manual to ensure this is appropriate for your specific model.
When winding new line, ensure it's wound tightly and evenly onto the spool, maintaining consistent tension. This prevents tangling and ensures reliable line feeding.