How to Put a Belt on a John Deere lawnmower, step by step


Many John Deere mowers use a belt and pulley system to transfer the engine power to the wheels and blades. A worn belt is a common issue with this type of lawnmower and is mostly caused by wear and tear after prolonged use. Putting a belt on a John Deere mower can be a bit technical as you have to remove several components before you can reach the whole belt. So, knowledge of different parts of the belt assembly is crucial in this task.

A worn out and frayed belt can also be the reason for your lawnmower to slow down unexpectedly. If your lawnmower starts cutting uneven, you should check the drive belt. This blog will help you change a belt on a John Deere lawnmower. 

How to Put a Belt on a John Deere lawnmower, step by step:

  • Step 1: Collect the needed equipment
  • Step 2. Position your mower to change the lawnmower belt
  • Step 3. Remove the attached components like spring pins and washers
  • Step 4. Remove the cutting deck
  • Step 5. Install the new and clean belt
  • Step 6. Slide the cutting deck back
  • Step 7. Verify all the connections and start the engine
How to Put a Belt on a John Deere lawnmower, step by step 1
(CC BY-SA 2.0) by Charles & Hudson

Depending on your John Deere lawnmower model, the above steps may differ. Always check the user manual for more information. We will now look into each step in more detail.

Changing the belt on a John Deere Lawnmower:

Changing a belt on a John Deere Lawnmower is not a very difficult task. We have split the job into different steps to make the whole process easier to follow. If you are less confident in your capabilities, it can be wise to ask a professional for help.

● Step 1. Collect the needed equipment:

Using the right tools makes the work much more comfortable. For this job, you need the following tools:

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

Besides the tools, you also need a replacement belt. Make sure you have a matching belt for your machine. That means that it must have the same length and shape. Check the user manual for more information and the part number. If you do not have it, you can try google or check the current belt if the type is still readable. If a belt does not have the right shape and length, it will loosen itself from the pulleys. A short belt will get damaged quickly and is not good for your whole drive train.

● Step 2. Park the lawnmower and lower the cutting deck:

Place the John Deere lawnmower on a smooth and level surface before you start to work. Disconnect the sparkplug cables, so you are sure the engine will not accidentally start. Leave transmission in gear and use the lawnmower parking brake so that it does not roll. Set the cutting deck to the lowest possible setting to see if you can remove the belt without removing the deck. The cutting deck is the compartment of the lawnmower that contains the blades. Removing the belt without removing the mower deck is not always possible. In that case, you need to remove the cutting deck. If you have a lawnmower lift, it will be easier if you lift your machine.

● Step 3. Remove the attached components like spring pins and washers.

With the cutting deck in the lowest position, you can now see the different components that hold the belt, like the pulleys, connecting rods, spring pins. The blades are connected to the belt with the help of these rods and pins. So, to put on the drive belt, you have to turn the blades aside. Now, pull the spring pin from the mower engagement drive cable placed on the cutting deck’s right side. Remove the spring clip by using a pair of pliers. This is flexible depending on the deck width, which is probably greater than 42 inches. If you can work on the belt pulleys without removing them, you may do so.

After pulling the cable out, lift it to take it out from the bracket. Extract the cable spring from the idler pulley bracket. Separate the rear draft arm from adjustable lift links on each side of the deck by eliminating the spring lock pins and washers.  Set all the parts aside so that they can be used later on.

Tip: Make a short video or some images of how the belt and other components are attached. This will make reattaching them much more manageable.

● Step 4. Remove the old belt.

To remove the belt, you have to remove the cutting deck on some lawnmowers. On other types, it is possible to replace the belt with the cutting deck present. To remove the cutting deck, take out the spring pin and washer from the mower deck bracket. Now remove the belt. Roll the belt around the engine pulley and then slide the cutting deck from beneath the John Deere mower.

Loosen and remove the screws that grip the belt shields with a screwdriver. Release the bolts on the two pulleys on the left-hand side with an adjustable wrench. In this way, you can loosen the gap between pulleys, making it easy to put on the belt. Then, take note of how the belt fixes around the pulleys on the cutting deck; check the belt channels, pulleys, and distance.

● Step 5. Install the new belt.

Clean the pulleys and other components if necessary. Install the new belt around the pulleys on the deck, following the old belt pattern. Tighten up the bolts on the two left-side pulleys with the adjustable wrench. Now, put on the belt shields if any back over pulleys on the sides of the deck. Tighten them with screws. Here, notice that when you add on a new belt, it is always better to grease the edges as the belt rubber is quite hard at the start. The greasing helps in freeing up the movement. It is also better for the life of drive pulleys.

● Step 6. Slide the cutting deck back.

Reattach all different on the cutting deck. Make sure the drive rods are correctly fastened. Now you can slide the cutting deck back beneath the John Deere mower. Check the correct working of the belt, and see if there is no restriction in its movement. The belt should not touch other parts of the lawnmower.

● Step 7. Check all the connections and start the engine.

Now it is time to reattach the last components. Put the rear draft arm and adjustable lift links on both sides of the deck back to the mower frame with washers and spring lock pins. Next, slide the mower engagement drive cable below the mower belt and brake rod. Pull the drive cable towards forward, then; line up the cable’s black end with frame enclosed to the cutting deck, and release in the bracket. Then, secure the cable to the frame with a spring clip.

After you are done, and everything is in order, you can reattach the spark plug cable. Start the engine and let the engine run for a few minutes. Check the sound of the engine and moving blades. If you notice no vibrations, you are good to go.

For a hands-on demonstration of how to put the belt on a lawnmower, you should watch this video:

Additional concerns:

When you work on a gas-powered Lawnmower, it is essential to look at several safety precautions:

  1. Wooden block: Place a wood block below both sides of the cutting deck for support or aid throughout the removal and installation process.
  2. Use genuine and certified parts: Then, get a suitable or appropriate replacement belt from a mower repair shop, hardware store, or home improvement store. Always use genuine and certified factory parts.

Frequently asked questions

1. Why does my belt keep keeps coming off my lawnmower?

If the belt on your lawnmower keeps getting off, there can be two main reasons. The first is if the belt is stretching due to wear and tear. To fix this issue, you need to replace the belt. The other is if the spring that keeps the tension on the belt is weak. This may happen when the lawnmower is getting older. To fix it, you need to replace the parts with the spring.

2. Does a lawnmower belt stretch?

Lawnmower straps stretch because of wear and tear to some degree. This is the same for all rotary machines. A very long period of continued use of these lawnmowers may stretch the belt a little bit. As the belt keeps on rotating at high RPMs and is also under load while it is in action, the belt gets warmed up and slowly starts losing its original shape.

3. Do you always have to remove the mower deck to change the belt?

No. There are several lawnmower types where belts can be replaced without removing the mower deck. Check the owner’s manual if this is possible with your lawnmower. If it is possible, always lower the mower deck to its lowest position, as explained in the above article, and then safely deal with changing the belt. Removing the deck has one big advantage as it allows you to clean and check other vital parts’ condition.

This video link will give you insight into putting a belt without removing the mower deck.

4. How can I know if my lawnmower belt is not working correctly?

Most lawnmowers that use a belt will experience a problem or breakage somewhere their lifespan. If a belt breaks, it will be clear what the problem is. But there can be minor issues like the belt being too loose or too tight as well. Signs for these minor issues are uneven cutting, noisy blades, and vibrations. If you check the belt itself, you can also see signs of these problems:

  • Sidewall damage: The belt has sidewall damage because the mower belt edges get rough over continuous use.
  • Burned sidewall: Generally, the belt may get a burned sidewall causing it to lose grip over time.
  • Extreme wear and tear: When you notice more excessive wear and tear, like a part of the belt that gets thinner or the outside of the belt is has been scrapped off.

Final remarks

There can be several reasons why you need to replace your John Deere lawnmower belt. A lawnmower drive belt connects the engine with the wheels and blade. The belt may get damaged or even break after prolonged usage. Replacning belts is not a very difficult task and can be done at home. Make sure you use the correct replacement belt with the same length and dimensions.

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