The following instructions are for trimmers, curved, straight, electric, or battery-operated that come with a threaded shaft that's 1" or shorter (if threaded on the inside). Not all straight shafts trimmers install this way and some curved shafts may follow these instructions.
If after unscrewing the original head AS A COMPLETE UNIT, you end up with a shaft that's about 2" long, threaded on the inside that can't be removed (not a shaft extender) then you should follow the Curved Shaft installation instructions instead. Keep in mind that most straight shaft trimmers are reverse threaded.
You can check the Brands section to see if your particular brand and model follows these instructions.
Most Echo, Husqvarna, Stihl, and Weedeater trimmers follow these instructions even if the models are curved shafts.
All our replacement heads follow the same basic set of instructions. There are a few GrassGator models that require some extra steps. Follow the instructions below regardless of the GrassGator head you are trying to install. If your GrassGator head requires additional steps then you will be prompted to click on a new link once you have reached that stage of the installation process.
DO NOT REMOVE THE DEFLECTOR SHIELD. We removed the deflector shield and used different trimmers on the pictures to show in more detail the parts relevant to the installation.
* From this point forward we'll use the term "straight shaft" for any trimmer, straight or curved, that follows these instructions.
* Your trimmer may not look exactly as the ones illustrated.
* Your GrassGator head may be a different model than the one illustrated but it will still follow the same instructions.
Check our "Brands" section to see if your model follows these instructions
In order to expose the threaded shaft needed to install the GrassGator head, you must remove the original head as a complete unit. You must lock the shaft before you can unscrew the original head. Most of the trimmers follow one of three styles:
Right on top of the gearbox, there's a metal collar with a hole cut on top. Use the tool that came with your trimmer and drop it down the hole. If yours didn't come with one you can use a nail, hex wrench, or drill bit. Turn the head a few times until the locking tool aligns with the hole on the plate inside the collar. The tool will sink a little bit deeper and the head will offer some resistance once you try to turn it opposite to how it normally spins.
Right above the original head, there should be a plate or metal collar with a hole or u-shaped slit cut on the side. If your deflector shield covers the plate, look for a hole in the deflector shield. Your trimmer may have come with a tool to lock the shaft (usually a metal rod). If yours didn't come with one then use a nail, screwdriver, or hex wrench instead. Insert whatever tool you are using into the slit and turn the head a few times. The tool will sink deeper locking the shaft. You'll notice that now the head will offer some resistance once you try to turn it opposite to how it normally spins.
Some brands like Weedeater have what looks like a pot metal "nut" right on top of the original head that wraps around the handle of the trimmer.
If that's the case with yours then hold the "nut" in place, don't let it move, and then unscrew the original head off as a complete unit.
With the shaft now locked, remove the original head as a complete unit.
Do not take it apart in pieces.
If you do that, you'll leave the "spool shaft" or "shaft extender" on. The "spool shaft" is a long hollow cylinder threaded on the inside that works as an extender to accommodate the original threaded bump knob. If left on, the shaft will be too long and there will be too much play between the top of the shaft and the GrassGator head which can damage the GrassGator or your trimmer.
If you can't remove the original head because it's held in place by a pressure washer or, if after unscrewing the head as a complete unit you are left with a shaft that's 2" or longer then please follow the Curved Shaft installation instructions.
If your trimmer came with a flanged washer between the gearbox and the head, DO NOT REMOVE IT or you won't have a way to lock the shaft again.
If your trimmer has splines that end up exposed, slide the included spline cover (thick plastic washer) over the shaft before the GrassGator head.
The spline cover is included with some of our models. If your GrassGator didn't come with one, call or e-mail us to request one for free.
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Next, find the correct fastener. The GrassGator kit comes with a pack of 7 nuts and 2 bolts. The right-hand threaded nuts are silver while the left-hand threaded nuts are brass colored.
Most straight-shaft trimmers have a shaft that's threaded on the outside (male). Very few have a shaft that is threaded on the inside If the shaft of your trimmer is threaded on the inside then find the bolt from the kit that fits the shaft. If the shaft is threaded on the outside then find the nut that fits the shaft. Keep in mind that most straight shaft trimmers are on a reverse thread so the nut will screw to the left.
The nuts in the kit may look the same but are in fact all different sizes. Some of them, however, are very close in size so you may find some nuts that start but then seize after a quarter turn. If that happens, don't force it, and try other nuts. For most trimmers, the required nut is included in the kit.
Once you find the correct nut or bolt, set it aside.
First, locate the bottom of the GrassGator head. The bottom of the GrassGator head is the side with the hex-shaped recessed hole. This is the side that should be facing the ground once the GrassGator head is in use.
Very important: The hex-shaped hole on the GrassGator head will NOT go over the hex on the top of the shaft.
The hex hole on the GrassGator head should be facing the ground.
Drop the nut or bolt you found on step 3 inside the hex-shaped recessed hole. The shank of the bolt should go through the hex-shaped hole and the head of the bolt should sit inside it. The nut must be completely inside the hex shaped hole.
On Fixed line heads like the 8010 and 5600, the bottom is the flat round side, not the side that sticks up
On bladed units (3600,4600,4680) and Multi-Tool units (4700 and 5620), the bottom is the flat round side, not the triangle side.
With the nut or bolt now inside the hex-shaped recessed hole, slide the GrassGator head over the shaft.
On bladed units, the triangle side goes against the spacer cup, round side with the nut facing out.
On pre-cut line units, the side that sticks up goes against the spacer cup, flat round side facing out.
The GrassGator head will work as a wrench. You may have to start the nut or bolt with your fingers but once the head of the bolt or the nut is inside the hex-shaped hole on the GrassGator head you can then keep turning the GrassGator head until it's tight. There should be no up-and-down play at all. The GrassGator head should be tight against the gearbox. Any gaps may damage the GrassGator head or your trimmer.
If there's no gap and everything is tight then, you are done and ready to use your new GrassGator!