Replacing the PTO clutch on your Cub Cadet is a standard maintenance task that most homeowners can tackle in an afternoon. The 01001979 clutch is a vital component that sits at the base of your engine crankshaft, and when it fails, your mowing comes to a complete halt. While the idea of working on the drivetrain might seem intimidating, the process is straightforward if you have the right tools and a clear plan. By doing this repair yourself, you save on shop labor costs and gain a better understanding of how your equipment functions.
Preparation and Safety First
Before you pick up a wrench, you must prioritize safety. Since you will be working directly underneath the engine and near the mower deck, you need to ensure the machine cannot start accidentally. Park the tractor on a flat, level surface and engage the parking brake to prevent any rolling. Remove the ignition key and disconnect the spark plug wire to eliminate any risk of the engine firing while you are handling the crankshaft bolt.
You will also want to gather your tools beforehand to make the job go smoothly. For a Cub Cadet 01001979 replacement, you typically need:
- A socket set with an extension, usually requiring a 5/8 inch or 16mm socket for the main bolt.
- A large screwdriver or a pry bar to help stabilize the clutch during removal.
- A torque wrench to ensure the new bolt is tightened to the manufacturer's specification.
- An emery cloth to clean the engine crankshaft.
- Anti-seize lubricant to prevent the new clutch from rusting onto the shaft in the future.
Once your workspace is clear and your tools are ready, you can move on to the actual teardown.
Removing the Old PTO Clutch
The first physical step in the replacement process is gaining access to the clutch. You will need to lower the mower deck to its lowest position to provide enough clearance to work. In some Cub Cadet models, you might find it easier to remove the deck entirely, though this is not always strictly necessary if you have enough room to reach the belt. To properly remove the old assembly, follow these steps:
- Release the tension on the mower drive belt by rotating the tensioner arm and sliding the belt off the clutch pulley.
- Locate the electrical wire harness leading to the clutch and carefully unplug the plastic connector.
- Inspect the connector for any signs of heat damage or melted plastic that might indicate a larger electrical issue.
- Secure the engine crankshaft to prevent it from spinning, which can be done with a strap wrench or by using a pry bar against the clutch body.
- Use your socket wrench to remove the central mounting bolt by turning it counterclockwise.
- Slide the old clutch assembly straight down and off the engine crankshaft, being careful as the unit is quite heavy.
If the clutch is stuck due to rust or corrosion, a light tap with a rubber mallet can help break it loose. Avoid using a metal hammer directly on the crankshaft, as this can mushroom the metal and make it impossible to fit the new unit.
Inspecting and Cleaning the Crankshaft
With the old 01001979 clutch removed, you have a perfect view of the engine crankshaft. It is common to find a buildup of rust, dirt, and old grease here. If you slide the new clutch onto a dirty shaft, it might not sit level, which leads to vibration and premature failure.
Take a moment to perform the following maintenance steps:
- Use your emery cloth to buff away any surface rust on the shaft until the metal is smooth and shiny.
- Inspect the keyway, which is the narrow slot where the square key sits to lock the clutch in place.
- Wipe the shaft clean with a lint free rag and a bit of solvent to remove any remaining grit or debris.
- Apply a thin, even layer of anti-seize lubricant to the entire length of the crankshaft to make future removals much easier.
Checking the key is also vital. Most clutches come with a built in key, but some require you to reuse the old one or install a new square key into the slot. Ensure the key is in good condition without any sheared edges or rounding that could lead to slipping.
Installing the New 01001979 Clutch
Now it is time to install the new unit. Line up the keyway on the clutch with the key on the crankshaft and slide the assembly upward. It should slide on relatively easily with minimal resistance. If it feels stuck, stop and check for burrs on the metal or a misaligned key.
To ensure a successful installation, follow these critical alignment steps:
- Align the anti-rotation pin on the tractor frame with the specific slot or hole on the top of the clutch housing.
- Ensure the clutch is pushed all the way up so that the pulley aligns perfectly with the other pulleys on the mower deck.
- Reinsert the mounting bolt along with the heavy duty washer, ensuring the threads are started by hand to avoid cross threading.
- Use your torque wrench to tighten the bolt to the manufacturer specification, which is usually between 50 and 55 foot pounds for this model.
- Verify that the clutch cannot spin freely by hand, which confirms the anti-rotation pin is correctly engaged.
If you miss the anti-rotation pin step, the clutch body will spin when you start the tractor, which will immediately rip the electrical wires out of the harness.
Final Connections and Testing
After the bolt is torqued, plug the electrical harness back into the new clutch. Ensure the wires are tucked away from any moving parts, high heat areas, or hot exhaust pipes. Use a zip tie if necessary to keep the wiring secure and out of the way of the drive belt.
Complete the job by following these final steps:
- Reinstall the mower deck belt onto the clutch pulley, making sure it is properly seated in the groove of the pulley.
- Double check the belt routing to ensure it hasn't slipped off any other pulleys or idlers during the process.
- Reconnect the spark plug wire and lower the tractor if it was on jack stands.
- Start the engine and set it to a medium throttle position.
- Engage the PTO switch to confirm the blades spin up quickly and without any strange vibrations.
A new clutch has an internal brake, and the blades should come to a complete halt within a few seconds of turning the switch off. If everything sounds smooth and the blades stop as expected, you are ready to get back to work.
Frequently Asked Questions
Why did my new clutch come with a new bolt?
It is often recommended to use a new bolt because the old one has been subjected to extreme heat and vibration cycles. A new bolt ensures the threads are perfect and the metal hasn't been stretched, providing a more secure hold for your 01001979 unit.
Do I need to "burnish" my new PTO clutch?
Burnishing is the process of engaging and disengaging the clutch multiple times to scuff the friction surfaces together. While many modern clutches come pre-burnished, it is a good practice to engage and disengage the PTO ten to fifteen times at mid throttle before you start cutting heavy grass.
Can I use an impact wrench to tighten the main bolt?
While an impact wrench is great for removing a stuck bolt, it is not recommended for tightening. It is very easy to over torque the bolt with an impact gun, which can lead to a snapped crankshaft. Always use a manual torque wrench for the final tightening.
How tight should the mower belt be on the new pulley?
The belt tension is controlled by the tractor’s spring loaded tensioner arm. You do not need to manually adjust the tension, but you should inspect the belt for wear. A new clutch provides a lot of grip, and an old, thin belt might snap under the new load.
Get Your Cub Cadet Back in Action
Replacing your PTO clutch is the best way to restore the cutting power of your Cub Cadet and ensure your lawn stays looking professional. By following these steps and taking the time to clean and lubricate the crankshaft, you are extending the life of your tractor and preventing future mechanical headaches. A high quality 01001979 clutch is built to handle the rigors of heavy mowing, providing you with years of reliable service.
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