How to Put a Belt on a John Deere Lawn Mower: Best Guide

How to Put a Belt on a John Deere Lawn Mower: Best Guide

The majority of John Deere lawn mowers use a belt and pulley system to transmit engine power to wheels and blades. It is common for this type of lawnmower to develop a worn belt after prolonged use, which is mostly caused by wear and tear. It is a bit tricky to change a belt on a John Deere mower as you have to remove several components before you can reach the belt. 

Knowing the different parts of the belt assembly is therefore essential. If your lawnmower slows down unexpectedly, it may also be due to a worn out belt. If your lawnmower starts cutting unevenly, you should check the drive belt. In this blog, we'll show you how to change the belt on a John Deere lawnmower. 

The task of changing a belt on a John Deere lawnmower is not very difficult. To make the process easier to understand, we have divided the work into multiple steps. If you are unsure of your abilities, it may be better to ask a professional for help.

● Step 1. Gather the necessary equipment:

It is much easier to do the work when you have the right tools. Here are the tools you'll need:

  • A pair of safety gloves
  • Set of Pliers
  • Screwdrivers
  • Adjustable wrench
  • Woodblocks or a lawnmower lift

You will also need a belt to replace the one you have. Check your machine's belt to make sure it's the right one. That means that it must have the same shape and length. For more details, check the user manual.

You can try Google if you don't have it or look at the current belt to see if it is still readable. Having the wrong shape and length for a belt can cause it to come untied from the pulleys. A short belt will wear out quickly and is not good for your drive train.

● Step 2. Position the lawnmower and lower its cutting deck:

Before you begin, make sure that your John Deere lawnmower is on a smooth, level surface. Make sure you disconnect the sparkplug cables so you won't accidentally start the engine. Keep the lawnmower in gear and use the parking brake to prevent it from rolling. Try lowering the cutting deck to the lowest setting to see if you can remove the belt without removing the cutting deck. 

Cutting decks are the compartments within which the lawnmower's blades are located. In some cases, it is impossible to remove the mower belt without also removing the mower deck. Therefore, the cutting deck must be removed. With a lawnmower lift, it is easier to lift your machine.

● Step 3. Remove the attached components, such as spring pins and washers.

By lowering the cutting deck, you can now see the various components that hold the belt, such as the pulleys, connecting rods, and spring pins. With these rods and pins, the blades are connected to the belt. In order to install the drive belt, you must turn the blades aside. 


Next, remove the spring pin from the mower engagement drive cable on the right side of the cutting deck. Remove the spring clip with pliers. Depending on the width of the deck, it may be greater than 42 inches. If you can work on the belt pulleys without removing them, go for it. Once the cable is out, lift it up to get it out of the bracket. 


Disconnect the cable spring from the idler pulley bracket. . Separate the draft arm on each side of the deck from the adjustable lift links by removing spring lock pins and washers. Set them all aside for later use. 


Tip: Make a video or take some photos showing how the belt and other components are attached. Seeing how they are attached will make reattaching them easier.

● Step 4. Remove the existing belt.

Some lawnmowers require removing the cutting deck before replacing the belt. With other types, it is possible to replace the belt if the cutting deck is present. Remove the spring pin and washer from the mower deck bracket to remove the cutting deck. Next, remove the belt. Roll the belt around the engine pulley and then slide the cutting deck from under the John Deere mower. 

Remove the screws that hold the belt shields with a screwdriver. Using an adjustable wrench, release the bolts on the two pulleys on the left. By doing this, you can loosen the gap between the pulleys, making it easier to put on the belt. Then, observe how the belt fits around the pulleys on the cutting deck; check the belt channels, pulleys, and distance.

● Step 5. Install the new belt.

If needed, clean the pulleys and other components. Follow the old belt pattern when installing the new belt around the pulleys on the deck. Use the adjustable wrench to tighten up the bolts on the two pulleys on the left side. 

Now you can put on the belt shields over the pulleys on the sides of the deck. You can tighten them with screws. Here, notice that it is always advisable to grease the edges of a new belt since the rubber is quite hard at first. Greasing makes it much easier to move. It also increases the life of the drive pulleys.

● Step 6. Place the cutting deck in its original position. 

Reattach the various parts of the cutting deck. Make sure the drive rods are properly secured. Now you can slide the cutting deck back under the John Deere mower. Ensure that the belt is properly working and that there are no restrictions to its movement. The belt should not touch any other parts of the lawnmower.

● Step 7. Ensure that all the connections are in place and start the engine.

It is now time to reattach the last component. Attach the rear draft arm and the adjustable lift links on both sides of the deck to the mower frame with washers and spring-loaded pins. After that, slide the mower engagement drive cable below the mower belt and brake rod. 

Pull the drive cable forward, then align the cable’s black end with the frame enclosed to the cutting deck, and release the cable from the bracket. Attach the cable with a spring clip to the frame. If everything is in order, you can reattach the spark plug cable. 

Turn on the engine and run it for several minutes. Check the sound of the engine and the blades as they move. If there are no vibrations, then everything is fine. 

You should watch this video if you want to see a demonstration of how to put a belt on a lawnmower: 

Additional concerns:

If you are working on a gas-powered lawnmower, take these safety precautions:

  1. Wooden block: When removing and installing the cutting deck, place a wood block below each side to support it.
  2. Use genuine and certified parts: You can also get a new belt from a mower repair shop, hardware store, or home improvement store. If you use any other type of parts, make sure they are genuine factory parts

Frequently asked questions

1. Why does my lawnmower's belt keep coming off? 

When your lawnmower belt keeps getting off, there are two main causes. First, the belt might be stretched from wear and tear. In this case, the belt should be replaced. Another possibility is if the spring that maintains the belt tension is weak. This could happen as the mower ages. To fix it, you must replace the spring. 

2. Can a lawnmower belt stretch? 

There are some cases where lawnmower straps stretch due to wear and tear. This is the case for all rotary mowers. After a long period of continuous use, a lawnmower belt may stretch slightly. Since the belt continues to rotate at high RPMs and is also under loads during operation, it gets warmed up and slowly begins to lose its original shape.

3. Does changing the belt always require removing the mower deck? 

Not necessarily. In several lawnmower types, the belt can be replaced without removing the mower deck. Check your lawnmower's manual to see if this is possible. If possible, lower the mower deck to its lowest position before changing the belt. You can learn how to do this in the article above. Removing the deck has the advantage that it allows you to clean and check other vital parts. 

4. What are the signs that my lawnmower belt needs to be replaced? 

In most cases, lawnmowers with belts will experience a problem or breakage at some point during their lifespan. When the belt breaks, it is evident what the problem is. However, there can also be minor issues like the belt being too loose or too tight. These minor issues can be detected by uneven cutting, noisy blades, and vibrations. 

Additionally, certain signs of these problems can be seen on the belt itself:

  • Sidewall damage: The mower belt has sidewall damage due to its edges becoming rough with continuous use. 
  • Burned sidewall: Generally, the belt loses grip over time if it develops a burned sidewall. 
  • Extreme wear and tear: When the belt shows signs of excessive wear, such as getting thinner or scratched. 

Final remarks

There are several reasons why John Deere lawnmower belts need to be replaced. The lawnmower drive belt connects the engine to the wheels and blade. The belt may break or become damaged after prolonged use. A belt replacement is not a particularly difficult job and can be completed at home. It is important to use a belt with the same length and dimensions as the original one.

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