Walker Blade Service
This Walker blade service guide will help you with DC36R, DC42R, DC48R, and DC52R decks. Extra care must be taken to install new blades, or reinstall sharpened blades properly. Walker mower decks can be confusing because they use different blades on each spindle, and they counter-rotate.
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Above is the image of the underside of the C52r deck positioned like it would be for changing the blades or cleaning the bottom. Note: I have a graphic indicating your left or right-hand side in this orientation.
When this deck operates, the left side blade spindle rotates counterclockwise. The green path shows the clipping path to the clipping flow. As the clipping approaches the discharge, the clipping flow enters the vacuum air stream at about a 90-degree angle from the left and right. The extreme airflow will change the clipping direction as they are pulled into the Grass Handling System. This style of deck is known as the Walker reverse rotation design.
Removing the blade nut
Tip-up the deck so you can look at it from the view shown. One nice thing about this gear-driven deck is that when tipped up with the drive shaft attached, the blades can not rotate. Thus, you don’t need any blocking to keep the blades from rotating. The locking action is provided by the universal joint of the drive shaft at a 90-degree angle, beyond its ability to transfer rotational motion. To make this happen, push the upper area of the deck toward the tractor. To remove the blade, use a deep well 15/16″ socket and rachet to turn the spindle nut counterclockwise to remove it. Under the nut should be a lock washer, flat washer, and blade assembly. The blade assembly will include the mower blade, two shear pins with nuts, and a blade cup.
How the shear pins work
Since this is a gear-driven mower deck, it is a positive drive, meaning that the drive will not slip under load or impact. If something is struck hard, the shock load is transferred through the drive train until something gives or the power driving it is overcome and stalls. To stall today high horsepower engine, the drive system would have to be designed to handle 100’s of horsepower. This is impractical for many reasons, like size, weight, and expense. So the engineers have designed this drive to be broken. You have heard the saying, “The chain is only as strong as its weakest link.” if you install a weaker, inexpensive, easy-to-replace link, you can predict which link would break when overstressed and protect the other more expensive, harder-to-replace links. The drive would have a lower capacity but more than enough strength to do the job yet protect the different components when overstressed. Using this design technique, you build a durable, lower-cost, lighter-weight drive designed to do the job. But when the drive is put into a situation not designed for, it will fail predictably and be easy and inexpensive to repair.
The weak link in this drive train
The blade assembly has a weak link built into it. These are the shear bolts, and they are easy to replace. Let me explain how this assembly works. The blade assembly has the blade cup, which, if you look at the center hole, has a double D hole. On each side of the center hole, you will see two 3/16″ holes for shear bolts. The two flat sides of the hole in the blade cup will engage with the two flat sides on the blade spindle shaft. The two small holes are used for the stainless steel shear bolts. Once the flats of the cup hole engage with the shaft, it will only rotate with the shaft.
Mount the blade below the blade cup. You notice the blade has a round hole in the center and two small 3/16″ holes on each side. The center is smaller in diameter and slips over the threaded area of the shaft. It can not engage with the spindle shaft and will rotate freely. To engage with the spindle shaft, you will need to install shear bolts through the blade cup smaller holes and the smaller holes in the blade. This will give you a drive train as follows: The shaft engages the blade cup through the flats on the shaft, the blade cup engages the shear bolts, and the shear bolts engage the blade. Now, the assembly turns as one.
After you install the blade assembly on the spindle shaft, Use your torque wrench to torque the blade nut to 60 ft. lbs. This is important, as too much torque will damage the blade if you hit something with it inadvertently, and too little torque will result in the blade shear bolts breaking without cause. Walker has placed a decal on the deck to remind you of this blade nut torque. It’s that important.
Tightening the blades
Use a Torque wrench set to 60 ft. lbs. equipped with a 15/16″ socket. I like to use a deep well socket because I am less likely to cause me to skin my knuckles. Tighten the nut clockwise until the torque wrench indicates you have tightened it to 60 ft. lbs.
Frequently asked questions
Why would my blades hit each other?
If the shear bolt is broken, the blades will be out of time and hit each other.
If the gear drive is out of time, the blades will hit each other.
Why do I keep shearing the shear bolts?
If you are using the wrong shear bolt, they must be stainless steel bolts.
The blade nut torque is not at 60 ft. lbs. Use a torque wrench to tighten the blade nut.
Why have I broken my deck gearbox?
You are repeatedly striking objects with blades.
It’s crucial to walk the lawn before mowing. Remove any trash and hidden objects that will get into the mower and cause damage. Mark any stumps or rocks so the operator can avoid them or remove or bury them so the mower can pass over them without striking them.
DC36R, DC42R, DC48R, and DC52R
How often should I sharpen my blades?
When your blades start stripping the grass stem tips, it’s time to sharpen them. If you examine your lawn after mowing, it should have a crisp, clean cut after the stem is removed. Using dull blades not only requires more power to cut the grass, but it also stresses the lawn more.
Deck Popular Parts Guide Menu
Please choose your model below to go to the popular parts list for your deck.
DC36R-1, DC36R-2, DC42R-1, DC42R-2, DC48R-1, DC48R-2, and DC52R-2
DC36R-1, DC36R-2
DC36R Popular Parts
This will give proper parts to fit on Walker Gear Driven Reverse Rotation Decks. For Models DC36R-1, and DC36R-2, |
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|---|---|---|
| Quantity | Part Number, Description | Note |
| 1 | 5705-36, Blade | Fits on Left |
| 1 | 5705-35, Blade | Fits on Right |
| 2 | 5706, Blade Hub | Fits Both Sides |
| 4 | F202 Shear Bolt | 2 on each blade & hub |
| 4 | F568 Shear Bolt Nut | Use on shear bolts |
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DC42R-1, DC42R-2
DC42R Popular Parts
This will give proper parts to fit on Walker Gear Driven Reverse Rotation Decks. For Model DC42R-2, |
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|---|---|---|
| Quantity | Part Number, Description | Note |
| 1 | 5705-3, Blade | Fits on Left |
| 1 | 5705-4, Blade | Fits on Right |
| 2 | 5706, Blade Hub | Fits Both Sides |
| 4 | F202 Shear Bolt | 2 on each blade & hub |
| 4 | F568 Shear Bolt Nut | Use on shear bolts |
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DC48R-1, DC48R-2
DC48R Popular Parts
This will give proper parts to fit on Walker Gear Driven Reverse Rotation Decks. For Model DC48R-2, |
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|---|---|---|
| Quantity | Part Number, Description | Note |
| 1 | 7705-1, Blade | Fits on Left |
| 1 | 7705-2, Blade | Fits on Right |
| 2 | 5706, Blade Hub | Fits Both Sides |
| 4 | F202 Shear Bolt | 2 on each blade & hub |
| 4 | F568 Shear Bolt Nut | Use on shear bolts |
Please take me back to the Beginning, Deck Popular Parts Guide Menu
DC52R-2
DC52R Popular Parts
This will give proper parts to fit on Walker Gear Driven Reverse Rotation Decks. For Model DC52R-2, |
||
|---|---|---|
| Quantity | Part Number, Description | Note |
| 1 | 7705-34, Blade | Fits on Left |
| 1 | 7705-35, Blade | Fits on Right |
| 2 | 5706, Blade Hub | Fits Both Sides |
| 4 | F202 Shear Bolt | 2 on each blade & hub |
| 4 | F568 Shear Bolt Nut | Use on shear bolts |
Please take me back to the Beginning, Deck Popular Parts Guide Menu