The belt on your trusty MTD lawn mower has unfortunately slipped off or has been damaged. You may be unsure if changing it is a job you can do yourself or if a professional is needed. Save yourself the travel time and repair fees because this is absolutely an issue the everyday person can solve with the right tools and this step-by-step guide.
We’ll show you the quickest, easiest, and most efficient way to change the belt on your MTD lawn mower so you can get back to your regular lawn care in no time. We’ll also answer common questions about why your belt might be slipping off and what you can do to prevent this. Belts can be purchased at your local MTD dealer or online at Amazon. I definitely recommend using an OEM (original equipment manufacturer) belt to ensure top quality and correct fit.
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Changing Belts on Push and Riding MTD Lawn Mowers
Before we get into the step-by-step process for this issue, we’d like to note that there are multiple models of MTD lawn mowers, and while this guide should work for the majority of them, some steps might require a bit of variation depending on the model you have.
MTD is a brand family that creates these market-leading machines, and so sub-brands include:
- Troy-Bilt® in the Americas
- Rover® in the Pacific
- WOLF-Garten® in Europe
- Yard Machines®
- Cub Cadet®
If your lawn mower has the stamp of any of these brands, it is considered an MTD lawn mower and is applicable for this guide.
Of course, since there is such a vast list of lawn mowers within each of these sub-brands, you’ll want to make sure the parts, particularly the belt you purchase for this guide, match your model. You can ensure this by checking the product number labeled on your old belt and purchasing a duplicate.
If you can’t read the number on the belt because it is worn off you can look up parts diagrams at MTD Parts.
That being said, let’s get into the step-by-step guide for this quick and easy process! The first guide is for a push MTD lawn mower, and the second is for a riding MTD lawn mower.
Changing the Drive Belt on a Push MTD Lawn Mower
Push lawn mowers are the traditional model most people own, particularly those with smaller yards and minimal lawn care needs. Because they are still an extremely popular choice, despite there being fewer MTD models available, we will start the belt-changing process with this guide first.
Here are the steps to replacing the drive on any MTD push lawn mower.
Step 1: Gather the Proper Tools
The task of changing your MTD drive belt is going to be much more difficult if you don’t have the right tools. Luckily, all you need are some basic ones you can find in nearly any toolbox.
For this guide, you’ll need:
- A screwdriver or nut driver set
- A ratchet/ socket wrench set
- 2 sandwich bags
- A block of wood
- Hand gloves
The screwdriver and ratchet/wrenches will help you remove bolts safely without stripping or damaging them, especially if they’re difficult to remove. You’ll then place those nuts and bolts into the sandwich bag for safekeeping until it is time to replace them.
The hand gloves and goggles are for preventative purposes to ensure your safety during this process. Of course, in addition to these tools listed above, you’re going to need your replacement drive belt handy.
Step 2: Make Sure Your Lawn Mower is Cool
You want to make sure your lawn mower is at optimal temperature before you start this process.
Since most traditional lawn mowers are still fueled by gasoline, it is extremely dangerous to work on these machines while they’re hot because of the dangerous fumes they might exude as you take them apart. If you’re not careful, the lawn mower could also catch fire because the muffler can ignite the vapors and create a blaze.
Therefore, your MTD lawn mower needs to be cool before taking it apart and changing the belt. So, if you were using it prior to changing the drive belt, you’re going to want to store it somewhere safe where it can cool down for 10-15 minutes. This will also help ensure you don’t injure yourself on hot lawn mower components or potentially damaging them.
Step 3: Find a Work Area
The average person loves to tinker with their lawn machines in the driveway after they’ve pulled it out of the shed or had a long yard work session. For this task, we highly recommend you find a location that shelters you and your MTD lawn mower from the elements since you will be removing various components for this process.
Ideally, you should have a large platform or workbench where you can place and strap your lawn mower, so it’s secure and easy to workaround. But, if the area with the amplest room is your garage or shed floor, that works just as well. As long as the surface is stable, flat, and spacious, it’s suitable for this task.
Step 4: Prep the Spark Plug and Fuel Tank
If you have a gas-fueled push MTD lawn mower, you’re going to want to start this process by unplugging your lawn mower’s spark plug and sealing the fuel tank.
Unplugging the spark plug should be easy, but to prep the fuel tank, you’ll want to stage one of those sandwich bags. Unscrew the lid to the fuel tank, lay the sandwich bag flat on top of the opening, and then screw the cap back on with the bag functioning as a tight barrier between the inside of the fuel chamber and the cap.
Doing this helps prevent any fuel you have inside your lawn mower from seeping out when you tip it upwards to change the drive belt.
If you have a battery-operated lawn mower, safely unplug the battery so you don’t accidentally turn on the machine while you’re changing the belt.
Remember to have your gloves and goggles equipped by the beginning of this step and keep them on for the remainder of the process.
Step 5: Tilt and Secure the MTD Lawn Mower
Once your lawn mower is properly prepped, you will tilt it upwards so you have easier access to the underside of the machine.
If you have your lawn mower on a platform or worktable, strap down the handle to provide more stability as you wrench off pieces. If you can’t strap your lawn mower to something, perhaps place a bag of sand or another soft, heavy object over the hand to keep it in place.
Now that your lawn mower is strapped down and secure wedge your wood block between the lawn mower’s blade and the deck. This will keep the blade from spinning and potentially injuring you while you loosen and remove it.
Step 6: Remove the Blade, Blade Support, and Blade Bolt
With your gloved hand placed firmly on the blade where the wooden block wedges it, loosen the blade bolt with the appropriate tool, most likely the socket wrench or ratchet.
After you have loosened and unthreaded the bolt, gently remove the blade, blade support, and blade bolt from the crankshaft. It’s important to keep a firm grip on these components as you remove and set them aside, as damaging the blade could decrease your lawn mower’s efficiency and lead to a pricy replacement.
Step 7: Remove the Bottom Drive Cover Mounting Screws, Debris Shield Mounting Bolts, and Debris Shield
Before we can get to the drive belt, there are a few more components we’ll need to remove first, but underneath and on top of the lawn mower.
Start by removing the bottom drive cover mounting screws and the debris shield mounting bolts. Make sure you safely store these bolts in the second sandwich bag or some sort of container to be reattached later. If you can’t tell the difference between the drive cover mounting screws and debris shield mounting bolts, you’ll want to store them separately and label them.
Once the screws and bolts are removed, you can gently remove the debris shield. You’ll have to twist and maneuver it off, so it freely comes away from the end of the crankshaft pulley.
Step 8: Roll the Drive Belt off of the Crankshaft Pulley and Remove the Crankshaft Pulley
Now we have access to the drive belt. It should be sitting on the crankshaft pulley, ready for you to pull off. If it’s not, then the belt has been knocked off or is too loose and definitely needs to be replaced.
You should be able to easily pull the drive belt off of the crankshaft pulley and then remove the crankshaft pulley entirely, leaving the end of the crankshaft. Make sure the drive belt is sitting beside the crankshaft end rather than resting around it, so it is easy to pull off later.
Step 9: Remove the Drive Cover
By this point, we’ve successfully disengaged one end of the drive belt, but we still need to disengage the other end before we can replace it.
To do this, unstrap or release the lawn mower handle and place it in the upright position. From here, use your screwdriver to remove the top drive mounting screws. If your MTD lawn mower has a height adjustment lever new to the top drive mount, you’ll need to release it before you can pull the drive cover off.
Step 10: Remove and Replace the Old Drive Belt
After you’ve removed the top drive mount, you should be able to see the drive belt. To remove it, unhook the belt keeper that secures the drive belt to the top of your lawn mower’s transmission. Then, pull the old drive belt out and slip the new drive belt over the transmission pulley and through the deck opening.
Step 11: Do It All in Reverse
Your new drive belt is not in place, so it’s time to put everything back the way you found it. Start by reattaching the belt keeper to the new drive belt on top of the drive pulley on the transmission.
Once the new drive belt feels secure, you can replace the drive cover, reconnect the height adjuster lever, and screw everything tightly into place.
After reinstalling these components, tip the lawn mower back and secure the handle as you did before so it’s stable for the remainder of the process.
Underneath, you’ll wrap the new drive belt around the crankshaft end and replace the crankshaft pulley. Make sure the crankshaft pulley indentions align when you are reinstalling it, or it won’t sit properly. When you’re certain it is on properly, you can roll the new drive belt onto the crankshaft pulley, so it sits snugly inside the pulley indent.
All that’s left to do now is replace:
- The debris shield
- The debris shield mounting bolts
- The bottom drive cover mounting screws
- The blade, blade support, and blade bolts
When replacing the blade, it’s best to tighten the blade bolt by hand at first, then secure the blade with your trusty woodblock and tighten it further with a torque wrench.
Following the completion of this step, you can remove the woodblock, handle secures, and plastic bag from the fuel tank, then reconnect the spark plug and consider the process complete.
Changing the Drive Belt on a Riding MTD Lawn Mower
While there are some similarities in the process of replacing a push lawn mower’s drive belt and a riding lawn mower, they aren’t exactly the same due to their significant differences in design. For this reason, and the fact that most MTD lawn mowers are riders, not push, we have created a separate guide.
As opposed to the push lawn mower process, which should take around 30-45 minutes, this process is a bit more involved, so you should set aside about an hour to complete it.
Step 1: Gather the Proper Tools
The goal of changing your MTD lawn mower’s drive belt is still the same, but since the design of a riding lawn mower differs so much from a push, you’re going to need slightly different tools. Before you begin, here’s what we recommend you have in addition to your replacement drive belt:
- Socket wrench set
- Torque wrench
Again, these are all tools most owners will have in their general toolbox, and the gloves and goggles are for safety purposes.
Step 2: Prepare Your Lawn Mower
Before you start removing components to get to your ground drive belt, there are a few things you should shut off and disengage on your lawn mower first for safety purposes.
Start by making sure the ignition is off and removing the key from the ignition. You don’t want your lawn mower on or even have a chance of it turning on during this process.
To further ensure this, lift the mower hood and disconnect the spark plug wire. Then, lower the mower deck to its lowest position using the appropriate lever. At the top of the lawn mower near the steering wheel, turn the lever that disengages the cutting blades.
Step 3: Start Detaching the Drive Belt and Other Components
There are a lot of components on a riding lawn mower that needs to be disconnected and removed for this process, so make sure you carefully store all of your nuts, bolts, and washers. It might also be best to have your lawn mower’s user manual handy in case you need to refer to its diagrams for additional support.
Underneath your MTD riding lawn mower, you should be able to see the ground drive belt wrapped around the engine pulley. Carefully remove the belt from the engine pulley and release the belt from the belt keepers.
Below your engine pulley, remove the front lift link support retaining pin and washer and store them somewhere safe. Then, detach the support (looks like a silver rod) from the deck. Next, move over to the left suspension arm, remove the clip, and detach the arm from the mower frame.
Afterward, remove the left rear deck bracket retaining clip and washer so you can then release the bracket from the deck.
Repeat the same process on the other side of the lawn mower, so both suspension arms and deck brackets are fully disconnected.
Knowing where all of these components are on your riding lawn mower is important, so if you’re unable to identify them visually, this is where your user manual will come in handy.
Step 4: Pull Out the Deck, Remove the Lock, and Disconnect the Blade Cable Spring
If you’ve properly disconnected everything in the previous step, you should be able to easily slide the deck out from underneath your lawn mower. Be careful not to pull it out completely yet, as you need to disconnect a few things first, and pulling the deck too hard could damage them.
After sliding out the deck, release the locking tabs with the help of some pliers and pull the blade cable out from the deck bracket. You can then disconnect the blade cable spring from the idler arm and set it aside for later use.
You can completely move the deck out from underneath your lawn mower to give you more workspace with all of that done.
Step 5: Remove the Deck Belt from the Idler Pulleys and Belt Guides
Before you start this step, make sure you know how your new deck belt should be situated underneath your lawn mower before you remove the old one.
If you don’t change your drive belt often and are unfamiliar with how it should be installed, either take a picture of your lawn mower’s undercarriage to capture how the old belt is sitting before removal. You can also refer to the user manual for this, as most have diagrams that will show you how the ground drive belt should be placed.
Once you’re confident you know how it should look with a new ground drive belt, you can go ahead and remove the old one from the idler pulleys and belt guides.
Step 6: Install the New Deck Belt and Slide Deck Under Mower
Route your belt around your pulleys using the reference guide or photo you took. Slide your belt under the deck and reconnect the blade spring and cable along with the arms and supports. Once you are confident all belt guides, clips and pins have been reconnected you will finish installing the belt.
Now that your deck is reconnected to your lawn mower frame, roll the new belt onto the engine pulley. Do this by pulling the deck belt from the right side of your mower to the pulley. While slowly turning the pulley, roll the belt onto the pulley. Make sure the narrow side of the v-belt is placed into the pulley grooves.
The belt should feel tight and secure after this step. You can check by pulling the belt around the pulleys to make sure it is moving around each pulley securely and is not loose.
To complete the process, reconnect the spark plug wire and lower the lawn mower’s hood.