Craftsman 42 Inch Mower Deck Belt Diagram with Replacement Guide

Deck belts usually run for a long time unless they get damaged due to misalignment during installation. I faced such problems too many times in my career as a mower mechanic. If the deck belt of your Craftsman 42-inch mower needs a replacement, you must know where the belt goes before removing the old belt.

The Craftsman 42 Inch Mower Deck Belt Diagram helps you understand the exact position of the deck belt. So, you can easily remove the old belt and install a new one. You should do this carefully because the deck belt must move freely.

It should connect the two spindles and the two pulleys on the deck. At the other end, the belt gets attached to the engine drive pulley that will spin the blades.

Let me show you the diagram and explain how this deck belt system works.

Read: John Deere 48 Inch Mower Deck Belt Diagram With Routing Guide

Craftsman 42 Inch Mower Deck Belt Diagram: Detailed Explanation

See the image below to understand how the deck belt is positioned.

Craftsman 42 Inch Mower Deck Belt Diagram (source)

The way you are looking at the deck belt diagram is the same as when you stand behind the 42-inch mower. The deflector chute should be on the right-hand side. Two plastic wheels and two deck wheels will be on the rear and front sides of the deck.

Position of Spindles

As you can see in the above image, the right spindle assembly is close to the chute hinge. It has a deck belt guard to keep the belt from dislodging. The belt goes into the V-shaped groove of the first spindle. It is important to remember while installing a new deck belt.

The left spindle is positioned on the far left side of the deck. In this diagram, the belt is marked with two parallel lines going together. The belt from the lower end of the right spindle goes directly to the lower end of the left spindle.

In the middle, there is a tensioner spring to keep the belt tension at an optimum level. It also ensures the belt stays in place while spinning.

Position of Pulleys

After going out from the top end of the left spindle, the belt goes into the left idler pulley. The left idler pulley is positioned at the right of the left spindle. Similarly, the right idler pulley is positioned at the left of the right spindle.

The left spindle and pulley are almost at the same level when you look from the top. But the right spindle is close to the lower end of the right idler pulley. After going out of the left idler pulley, the deck belt directly goes into the engine drive pulley.

Though it isn’t shown in the diagram, you can see the circular shape of the belt at the top of the diagram. Then, the drive belt comes to the outer end of the right idler pulley. This way, the engine drive belt is connected to the two spindles and two pulleys on the mower deck.

Read: John Deere 54 Inch Mower Deck Belt Diagram – [Just 3 Checkpoints]

How to Replace Craftsman 42 Inch Mower Deck Belt?

Now you have the belt diagram and know where the belt goes. So, replacing the deck belt on your Craftsman 42-inch mower will be much easier. But there are some steps you can’t miss for safety reasons. Let me show you the steps.

Step 1: Turn the Mower Off

Before you attempt a repair or replacement, turn the ignition key off. Then, remove the key from the ignition.

Step 2: Lower the Deck

Adjust the deck adjustment lever to lower the mower deck. The deck should be at the lowest position.

Step 3: Turn the Clutch Actuator Lever Off

The clutch actuator lever is below the steering wheel. Move it to the Off position. Then, remove the clutch cable from the retainer.

Step 4: Remove the Retaining Pins

Retaining pins are small curled pins that hold the support arms in place. You should push these pins out and detach the support arms. It is necessary to remove the deck from the frame. Remove all four retaining pins.

Step 5: Remove the Deck Belt from the Engine Pulley

Reach the lower part of the frame. The deck belt is attached to the engine pulley, and it goes through two belt guides. Pull the belt out of the belt guides first. Then, remove it from the engine pulley.

Step 6: Pull the Deck Out

The mower deck is now detached from the frame. Slide it out of the frame. Be careful during this step because the blades are sharp.

Step 7: Remove the Old Belt

First, you should move the support arms out of the way. Then, take the belt out of the right idler pulley. Pull it upward to remove the belt from the belt guide. Then, take it out of the right spindle assembly. Now, you will remove the belt from the left spindle and left idler pulley.

Step 8: Install the New Deck Belt

Take a new deck belt. At first, you should attach it to the right spindle. When installing, make sure the V-shaped groove of the belt is going inside. This is because the groove of the spindle is V-shaped.

Then, attach the belt to the left spindle. The V-shaped groove should go inside here, too. After that, you should align the belt with the idler pulleys. In this case, the flat side of the belt will go inside because idler pulleys have flat grooves.

Read: Craftsman 30-Inch Riding Mowers With Cutting Deck In (2023)

Step 9: Align the Belt with the Engine Pulley

Slide the mower deck underneath the frame and make sure the V-shaped groove goes inside the engine pulley. Then, pass the belt through the belt guides to secure them.

Step 10: Secure the Deck with Support Arms

Attach the support arms using retainer pins. Also, attach the clutch cable.

That’s it. You have successfully replaced the deck belt of your Craftsman 42 inch mower. You can check this video to see how the deck belt is positioned in real life.


frequently asked questions (FAQs)

Check the answers to some commonly asked questions about Craftsman 42 inch mower deck belt.

Q: What size is a 42 inch deck belt?

A 42 inch deck belt is 96-5/8 inches in length. The width of the belt top is 1/2 inches.

Q: How many belts are on a craftsman 42 inch lawn mower?

You will see two belts on a Craftsman 42 inch mower. One is the deck belt and the other is the drive belt.

Q: Are deck belts and drive belts the same?

No. The drive belt transmits engine power to the mower wheels so that the mower can move. But the deck belt transmits engine power to the blades to spin them.


Handling a Craftsman 42 inch mower deck belt can be tricky, especially if you are a new user. But with a detailed diagram of the deck belt and an explanation of how the belt works, it will be much easier.

So, I provided a Craftsman 42 inch mower deck belt diagram and explained the position of the belt on the deck. If the belt isn’t positioned correctly, the blades won’t spin, and the belt can be damaged. So, make sure you follow the replacement guide carefully.

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