One of the main issues I had with my push lawn mower is that the front wheels kept falling off. The lawn mower is in perfectly good condition and isn’t actually that old, but no matter what I tried, the front wheels just kept falling off.
With a bit of research, I found out that push lawn mower wheels are held on by a number of different factors, and unfortunately, all of them can go wrong. So, let me share with you what the different ways are and what can go wrong. Hopefully, this will help you fix your lawn mower wheel so you can get back to mowing.
Why Does My Lawn Mower Wheel Keep Falling Off? (The Short Answer)
The wheel on your lawn mower is probably falling off because there is an issue with the wheel retaining nut, a clip washer, a missing cotter pin, or a problem with the thread of the wheel axle. To stop the wheels from falling off, you’ll need to investigate the retaining nut, cotter pin, clip washer, and the lawn mower’s axles for any missing or damaged parts.
A Closer Look at Why Your Mower Wheel Might Be Falling Off
To get a better understanding of why your wheel fell off your lawn mower, let’s take a look at the different components designed to hold the wheel in place.
The Wheel’s Retaining Nut
The wheels on your push lawn mower are usually held onto the axle by a nut. Now, the nut will almost always be some type of lock nut that has a nylon insert that prevents the nut from spinning even when it is loose.
So, grab a socket wrench and remove the nuts from your lawn mower’s axle for each wheel. Then, take a look inside that nut to see if the nylon insert is still in place and looks to be in good condition. If it’s missing or it looks like it might not be doing its job, then you’ll need to find a replacement.
A test you can do once the nut is loose is to try to remove it with your fingers. If there isn’t any resistance, then this is a sign it’s no good.
Checking the Cotter Pin is in Place
Most of the push lawn mowers you’ll come across won’t use a lock washer with a nylon insert. Instead, they’ll use a cotter pin. This is a pin that passes through the axle of the wheel and then splits apart to hold itself in place.
Once the pin is installed, the nut holding the wheel on will no longer be able to fall off. So, take a look at the end of the axles and check to see if there is a tiny hole. If there is, then you know your axle should have a cotter pin. If your pin is missing, then this is why your wheel keeps falling off.
Checking if the Clip Washer is in Place
The third method I’ve seen for holding on push lawn mower wheels is with a clip washer. A clip washer is a washer with a section missing. It is designed to clip into a groove on a metal bar. In your case, it would be the end of the wheel axles.
So, take a look at your axles and see if there is a groove. If you find a groove cut into the axle, then there should be a clip washer installed to keep the wheel from falling off.
Lawn Mower Axle
The final reason I have seen a lawn mower wheel fall off is because of a damaged thread on the axles. This is usually caused by the bolt being cross-threaded at some point, and it can’t hold the nut in place anymore.
So, thread the nut onto the axle and check to see if it goes on without a problem. If it’s a struggle or feels loose, then you might find that the axle threads have been damaged. If this is the case, double-check that the nut isn’t damaged and inspect the threads.
You can usually tell if an axle has been cross threaded just by looking at it. If the threads look squashed or misaligned, then you’ll need to look for a new axle.
Fixing a Lawn Mower Wheel that Falls Off Regularly (Step By Step)
I’m guessing that out of these four potential issues, you found one that matches up with your lawn mower. So if your lawn mower wheel keeps falling off, here’s what you can do.
Replacing the Lock Nut with Nylon Washer
The trickiest part about replacing the nut is to find the exact replacement. So, you’ll need to look in the service manual and look for the axle bolt. This will tell you the dimensions of the bolt, including the size of the thread. Failing this, you can just take your bolt to the hardware store and have one of the store assistants help you out.
Stores like Home Depot, Lowes, and Ace Hardware all sell nuts individually, so you’ll only need to purchase what you need. So once you have your replacement nut, just attach the wheel and install the nut using your socket wrench.
Tools & Parts to Install a New Wheel Nut
- Replacement Lock Nut with a Nylon Insert
- Socket Wrench Set
Installing a New Split Pin
If your split pin is missing, you’ll need to head to the hardware store to find a replacement. You’ll need to make sure that you get a new pin that fits the hole in the axle. So, once you have your new split pin, go ahead and reattach the wheel and the nut if there is one.
Then, thread the new split pin through the hole in the axle. Next, use a pair of pliers to separate the split pin and bend each section of the pin back around the axle and nut. You just need to make sure that the split pin can’t get back through the hole in the axle.
Alternatively, if you’re in a bit of a bind and you can’t find a replacement pin, then you can use pretty much anything metal that will fit through the hole in the axle. In the past, I’ve used a thin wood nail and even a large gauge wire.
Parts & Tools to Install a Split Pin
- Replacement Split Pin
- Pair of Pliers
Installing a New Clip Washer
If you found a groove at the end of your lawn mower’s axles, then you need to install a clip washer. Now removing a mower wheel retaining clip is much easier than installing one. But if you have a good pair of needle nose pliers, you should be ok.
So, head down to the hardware store and find a new clip washer. If you have one on another wheel, then I suggest you remove it and take it with you or take a look in the parts manual so that you get the right clip washer.
Once you have your new clip washer, reattach the wheel and any washers, then place the clip washer onto the axle. What you’ll want to do is slot the opening in the clip washer into the groove of the axle, then clip it into place using your needle nose pliers. Just watch out for your fingers.
Tools & Parts to Install a Lawn Mower Clip Washer
- Replacement Clip Washer
- Needle Nose Pliers
Replacing a Lawn Mower’s Front Non-Drive Axle
Replacing a lawn mower’s non-drive front axle takes a little more work and a few extra tools. So, if you have a lawn mower like a Craftsman Precision Plus or similar, you’ll be able to swap out the axle assembly and stop your lawn mower wheels from falling off.
Also, this can fix a lawn mower with a wobbly wheel. So, let’s go over the steps to replace a lawn mower’s front non-drive axle.
Raise the Front of the Lawn Mower
First, find something to jack up the front of the lawn mower so that you can remove the front wheels. Usually, I just grab a piece of wood, like a 4×4, that I have sitting around in my garage.
Remove the Wheel Covers
Next, use a flat-headed screwdriver for popping off the wheel covers. If you look around the cover, you should see a little missing piece of plastic. This is where you can put the screwdriver without messing up the cover.
Remove the Retaining Nut, Clip Washer, Split Pin
Then, remove whatever retaining method your lawn mower uses to keep your wheels on your lawn mower. This could be a nut, clip washer, or split pin. So, use a socket wrench, flat-headed screwdriver, or a pair of pliers, respectively, and remove the retainer.
Remove the Wheels & Any Washers
Once the retainers are removed, you can then remove the wheels, including any washers and bushing, then set them to one side for later.
Tilt Over the Lawn Mower
Next, you’ll need to tilt over the lawn mower the correct way so that oil doesn’t flow into the air filter. This is done in the direction that keeps the air filter pointing up.
Move the Plastic Retaining Tabs
Then, use a screwdriver to push the axle retaining tab out of the way. This can be a bit fiddly as you might need to move the plastic tab while you pull the axle. So, you’ll definitely need both hands. Now, not all lawn mowers will use this kind of axle locking method, so you might need to remove a bracket of some kind if your lawn mower is different.
Pull Out the Old Axle
Once the old axle is no longer locked in the body of the lawn mower, you can pull the old axle out of its mounting position and set it to one side to be trashed later.
Install the New Axle
Next, take your new axle and position it on your lawn mower, making sure you have it the right way around. Then, push the axle into the plastic tabs and click it into place. For you guys with other axle mounting systems, you’ll need to put them back into place and make sure the axle is properly secured.
Upright the Lawn Mower
With the new axle installed, you can go ahead and upright your lawn mower. You are now finished working under your lawn mower.
Jack Up the Front of the Lawn Mower
Next, use your block of wood to jack up the front of the lawn mower so that you have enough room to install the wheels.
Reattach the Wheels & Washers
Now, reattach the lawn mower wheels making sure that you install all the washers, bushing, and wheels in the correct order. If you get this wrong, you could end up damaging the plastic wheels.
Install the Wheel Retainer
So, you’re nearly finished with this fix. Next, install the retainers that hold the wheels on the lawn mower and stop them from falling off. So, either install the lock nut with the nylon inserts, the split pin, or the clip washer using the method in the previous fixes.
Replace the Wheel Covers
Finally, grab your wheel covers and reattach them back onto your lawn mower. I find that if you line them up on the wheels and then give them a firm tap with your palm, they should go back on easily.
Lower the Lawn Mower
The last thing to do is remove the piece of wood that is jacking up the lawn mower and give the mower a test run.
Tools & Parts to Replace a Lawn Mower’s Front Non-Drive Axle
- Block of Wood
- Socket Wrench Set