To prevent premature wear on your lawn mower spindles and pulleys, you’ll want to make sure that you are greasing them on a regular basis. Grease helps to avoid issues such as failing bearings and early belt wear. So, what is it that you actually need to do, and which spindles should you be taking care of? Well, let’s take a closer look at a few different lawn mower designs and find out how to grease lawn mower spindles.
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How to Grease Lawn Mower Spindles (Overview)
To grease a lawn mower’s spindles, locate the grease fittings on your mower. Then attach a grease gun to the grease fittings and inject a suitable grease into the spindle/pulley/bearing location. Once the grease begins to leak out of the pulley, you can move on to the next spindle.
Which Lawn Mowers Need to Be Greased?
Most lawn mowers that use belt and pulley systems to turn the cutting blades have some type of pulley spindles. Now the pulleys that are fixed and do not rotate are not the type of pulleys that need to be greased. So, for example, the pulleys fixed to the drive shaft or the PTO do not need to be greased. This is because they don’t actually rotate independently and don’t have spindles.
So, pulleys such as the idler and blade pulleys are the ones you need to take care of. Therefore, if you have a riding lawn mower such as a tractor or a zero-turn, you’ll find several pulleys attached to spindles. These are the spindles you’ll need to grease on a regular basis.
To learn more about maintaining your mower, head over to my article on how to inspect a riding mower.
Why Grease Lawn Mower Spindles?
When a lawn mower’s blades run at full speed, they rotate the pulleys at several thousand RPM. This means the friction of the bearings and pulleys moving over each other on the spindles creates a lot of heat. So, to reduce the amount of friction, you need to grease the spindles, bearings, and pulleys. If you don’t grease your lawn mower’s spindles, then you will run into a number of problems. Here are a few common symptoms caused by not greasing lawn mower spindles.
- Bearing Damage
- Potential Damage to the Spindle & Pulley
- Stress on the Lawn Mower’s Engine
- Stress on the Deck Belt
- Reduced Blade Speed
- Reduced Cut Quality
How Often to Grease Lawn Mower Spindles
Well, this really comes down to what your lawn mower manufacturer recommends. For example, John Deere recommends that you should grease your lawn mower every 25 hours, whereas Scag recommends greasing every 40 hours. However, I always like to edge on the side of caution and go for the lower number. This means I make sure to grease my spindles every 20-25 hours of use, and it is one of my maintenance tasks when getting my lawn mower ready in the spring. Spending a few dollars and minutes greasing my mower is way easier than having to replace a spindle or make repairs like replacing a lawn mower’s idle pulley.
What Grease to Use on Lawn Mower Spindles
When looking at the different grease options, you’ll soon find out that there are lots to choose from. This is because different greases are designed for different applications. For example, if you are looking for grease for your John Deere lawn tractor, you’ll find that John Deere offers several options, including synthetic, polyurea, HD lithium, and lithium, just to name a few. Now, any of these will work, but you’ll pay a premium for features you don’t need.
For example, JD synthetic greases are designed for high-pressure and high temperatures, which your lawn mower doesn’t call for. A deck spindle should only reach a temperature of around 200 degrees, so an HD synthetic grease that can withstand -45F/+450F and extreme pressures is totally overkill. Therefore, a less expensive option like general-purpose lithium grease will do just fine.
What Tools Do You Need to Grease a Lawn Mower?
A grease gun is the main tool you need to grease your lawn mower spindles. Now these come in various shapes and sizes, plus they are available in manual and powered versions. So, depending on how often you use your lawn mower and how quickly you put hours on the clock, you may want to go for a powered version. But for a general homeowner, a standard manual grease gun will work just fine.
Here are a few examples of the different grease guns you can use:
Now the one thing to remember is that you need to purchase the right tube of grease to fit your specific grease gun.
What Else Needs to be Greased on a Lawn Mower?
If you look through the grease servicing section in your owner’s manual, you’ll find that it’s not just the spindles that need to be greased. Depending on the design of your lawn mower, you may have to address a few extra items. Thankfully, you can use the same grease and grease gun for everything. Here are a few examples of other components on your lawn mower that you might need to grease.
- Wheels
- Caster Wheels
- Caster Yokes
- Deck Lift Mechanisms
- Steering Mechanisms
Can You Over Grease a Lawn Mower Spindle?
The simple answer is no. This is because the spindles and bearing on most lawnmowers are not under pressure. So, once a spindle is full of grease, the excess grease will leak out. Once grease begins to leak out of the spindle and bearing housing, you’ll know it is full.
How to Grease Lawn Mower Spindles (The Steps)
Now let’s take a closer look at how to grease a lawn mower spindle and the steps you’ll need to follow.
- Clean the Grease Fitting
- Attach the Grease Gun
- Pump the Grease Gun
- Watch for Leaking Grease
- Detach the Grease Gun
- Clean Up the Spindle
- Move on to the Next Spindle
Clean the Grease Fitting
First, use a shop rag to clean off the grease fitting on your lawn mower. This will prevent the grease gun from pushing any dirt or grit into the spindle housing, which would cause extensive damage to the bearings.
Attach the Grease Gun
Next, push the end of your grease gun onto the grease fitting. You should feel the nozzle of the grease gun clip onto the grease fitting once it is secure.
Pump the Grease Gun
With the gun in place, begin to pump the grease into the spindle. Depending on the size of the spindle and the amount of grease the spindle can take, you may need to pump the grease gun a few times.
Watch for Leaking Grease
During the pumping process, keep an eye on the spindle’s top and bottom for leaking grease. Once the grease begins to leak from both ends of the spindle, you can stop pumping, as leaking from both ends indicates that the spindle housing is full.
Detach the Grease Gun
Once you are happy that the spindle is full of grease, you can remove the grease gun from the grease fitting. Depending on the design of the grease gun, you may be able to just firmly pull the nozzle from the grease fitting, or you may need to unclip it. I recommend that you look over the grease gun instructions to check how you should detach your gun once you are finished greasing, as you don’t want to break either the gun or the grease fitting.
Clean Up the Spindle
Next, use a shop rag to clean off any excess grease that leaked from the spindle and the grease fitting. Now this isn’t essential, but the grease could work its way onto the pulleys and belts once you start up your lawn mower and cause some belt slippage. Plus, you’ll find everything will stick to the grease once you start mowing, including your clean pants and lawn.
Move on to the Next Spindle
Finally, once you have finished the first spindle, you can move on to the rest of the spindles and other grease fittings on your lawn mower and repeat the same process over again.
