John Deere 42 Inch Mower Deck Parts Diagram (Visula Guides)

Every time you lay eyes upon your perfectly manicured lawn, it makes you appreciate the prowess of your John Deere mower. But, have you ever wondered what makes it so good at its job?

What lies underneath its exterior that makes it deliver such pristine cuts? This John Deere 42-inch mower deck parts diagram will meet your curiosity.

John Deere 42 Inch Mower Deck Parts Diagram: Get To Know What Lies Underneath

The Mower deck parts diagram is a visual guide to the inner workings of a John Deere mower deck. It helps you understand how the mower deck works and makes it easier to troubleshoot malfunctioning parts.   

John Deere 42 Inch Mower Deck Parts
John Deere 42 Inch Mower Deck Parts Diagram (Courtesy:

John Deere LH Belt Cover (1)

The deck belt cover is a protective casing that safeguards the belts from dirt, grass clippings, and other debris. It keeps the belt clean and ensures smooth operation over time.

It can also prevent moisture from seeping into the belts, which is important to extend the lifespan of the belt, especially in hot and humid climates. 

John Deere Self-Tapping Bolt (2)

The self-tapping bolt attaches the belt cover and other components to the deck. These bolts make assembly easier as you don’t have to tap them before screwing them in.

Also, they establish a stronger connection than regular bolts since they create more precise threading. 

John Deere 10 MM Lock Nut (3)

The 10mm lock nuts keep the mower deck components attached to the frame. 

John Deere Flat Idler Pulley (5)

The flat idler pulley maintains tension in the mower’s deck belts. The mower will not be able to implement maximum cutting force without proper tension across the belts.

So, the flat idler pulley plays a vital part in mower functionality. It can also minimize the load on the mower engine by reducing the tension on the belts. 

John Deere 42″ Deck Drive Belt (6)

A deck drive belt connects a lawn mower’s engine to its cutting blades and transfers power from the engine to the blades.

If the deck drive belt becomes damaged or worn, the blades could stop spinning and render the mower useless.

John Deere Spindle Nut (8)

The spindle nut is a handy little fastener that is responsible for securing the spindle to the deck, which, in turn, connects the cutting blade and rotates it to slice through that pesky grass.

The spindle serves as the bridge between the deck and the blades. 

John Deere Spindle Drive Sheave (9)

The spindle drive sheave is a pulley-shaped device that drives the spindle and enables the cutting blades to rotate and expertly mow your lawn. 

John Deere Bushing (10)

These cylindrical components are used in a lawn mower deck assembly that serves as a type of bearing. They provide a low friction surface for the deck’s mobile parts to move on.

You can find bushings on several parts of a lawn mower deck, including the spindle and idler arms. 

John Deere Extension Spring (11)

An extension spring is a coiled metal wire spring that provides support to the mower blade belt and the idler arm. It keeps the mower belt taut and prevents it from slipping. 

John Deere Torsion Spring (14)

The torsion spring is also a coiled metal wire spring, but it varies slightly from the extension spring we just discussed.

It is responsible for delivering the necessary rotational force the belt would need for optimum cutting performance. 

John Deere Retainer Clip (15)

Retainer clips hold various components attached to the deck. It’s one of the reasons the mower doesn’t fall apart when you operate it throughout the lawn. 

John Deere M8x25 Screw (16)

These are screws that have a shaft diameter of 8mm and a thread length of 25mm

John Deere Blade Brake Pad (17)

The blade brake pads slow down and stop the mower blade when they come in contact with it.

This is an essential safety feature in lawnmowers that can help avoid dangerous accidents while operating them. 

John Deere Lock Nut (18)

The lock nut secures the blade onto the spindle. If it gets loose, the blade might fall out of the mower and hurt the operator or bystanders.

John Deere Bracket (19)

The bracket supports and stabilizes various parts of the deck.

John Deere RH Belt Cover (20)

The RH (Right Hand) belt cover shields the belt and pulleys on the right-hand side of the mower deck.

John Deere Deck Spindle (21)

In a mower deck assembly, a spindle is a rotating part that is driven by the engine’s pulley system and holds the cutting blade in place.

John Deere 42″ 3-in-1 Mower Blade Set (22)

These are the blades that cut the grass on your lawn. 

John Deere Blade Lock Nut (23)

Blade lock nuts fasten the blade to the spindle.

John Deere Blade Washer (24)

The blade washer goes between the blade and the spindle for optimum load distribution. 

John Deere 5/8″ Spindle Shaft (25)

The spindle shaft joins the spindle assembly to the deck. 

John Deere Belt Cover Rod (26)

The belt cover rod maintains the balance of the belt when it’s operational. 

John Deere Deck Idler Pulley (4A, 4B)

The deck idler pulley is located near the spindle or the blade pulleys. 

John Deere Deck Rod (7A, 13A, 13 B)

It adjusts the mower deck height. 

John Deere Deck Idler Arm (12A, 12B)

The deck idler arm mounts on the pivot and connects to the deck idler pulley. It helps to maintain proper tension and alignment of the mower deck belt.

John Deere Belt Diagram 42 Inch

John Deere Belt Diagram 42 Inch
John Deere 42 Mower Deck Belt Diagram (Courtesy:

The John Deere 42-inch mower deck features three cutting blades. Each of the blade is covered by spindles.

The belt comes around the flat idler pulley and adjacent spindle to go all the way back to the tensioner pulley and the front deck spindle. From there, it goes back around and back to the front of the motor. 

Final Words

The John Deere 42 Inch mower deck parts diagram could be difficult to decipher without adequate information.

We have pointed out every component in this piece so that you have no trouble identifying them.

If you need to have a look at the mower deck assembly of your John Deere mower, having a glance at this article could be helpful.

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