The pulley got stuck on my lawn mower, and no matter what tool I tried from my toolbox, I just couldn’t get it off. What I thought was going to be a five-minute job turned into a whole afternoon.
After a lot of banging and bruised knuckles, I eventually discovered what tool I should have actually been using from the start. So, if you’re having trouble removing a pulley from your lawn mower, then let me share with you the tool you need.
Problems a Stuck Lawn Mower Pulley Can Cause
Before we get into what tools you’ll need and the process for how to remove a stuck lawn mower pulley, let’s take a look at why you might want to remove one in the first place.
Well, pulleys can get damaged if they are struck with something hard enough, but it’s actually what they are attached to that is usually in need of replacement.
For example, If you need to replace a bad mower deck spindle because the bearings are worn, or replace a gasket on the engine sump, then you’ll need to remove the pulley first because it’s in the way.
What You’ll Need to Remove Your Mower’s Stuck Pulley (Equipment List)
Ok, now that we’ve gone over a few reasons why you might need to remove a pulley, let’s take a look at the different tools you’ll need to use.
Tools to Remove a Stuck Lawn Mower Pulley
- Socket Wrench Set
- Blade Brace
- Harmonic Balancer Puller (Pulley Version)
- High-Intensity Heat Torch
Socket Wrench Set
Pulleys are usually held in place with either a center bolt or a bolt through the side of the pulley shaft. So, to remove this bolt, you’ll need a socket wrench that matches the size of the bolt.
Also, if you need to remove a pulley from a driveshaft, you’ll need one wrench for the pulley and another for the top of the flywheel. This is so that you can stop the driveshaft from spinning when you remove the pulley bolt.
If you have a stuck pulley on a deck pulley, then you’ll need to first brace the blade so the pulley can’t spin while you remove the pulley bolt. This is just like having a second wrench to stop the drive shaft from spinning. For this, I like to jam a 4×2 piece of wood against the blade, or you could use a blade brace tool.
Harmonic Balancer Puller
I can already hear you asking, “what is a harmonic balancer puller?”. Well, this is the special tool I was talking about earlier. It connects to the pulley and then presses against the shaft. Now, this could be either the deck pulley spindle or the driveshaft.
So, the harmonic balancer puller pulls the pulley using force against the shaft as you tighten the puller’s center shaft. The benefit of this tool is it applies a balanced pressure against the pulley so that it comes off straight.
Also, because of the way the threads of the puller center bar are designed, you need little input effort to achieve a large output force. Kind of like riding a bicycle up a hill in first gear rather than fifth gear.
Power Drill & Metal Drill Bits
To connect a harmonic balancer puller to a pulley, you’ll need to drill a couple of holes through the pulley. This is so that the pulley has something to pull against. You’ll find that harmonic balancer pullers come in a couple of different designs. Ones for removing bearings and ones for pulleys. So be sure to get the one for pulleys.
Also, within the pulley kit, there are a few bolts that pass through the puller and through the pulley. What you’ll need is a drill bit big enough to drill your pulley for the bolts to pass through.
High-Intensity Heat Torch
Once you get onto removing the stuck pulley, you might find that you still can’t get it off. Well, this is where a heat torch comes in handy. If you heat the shaft of the pulley, the metal will expand, and you should then be able to remove the stuck pulley. I use a Bernzomatic high-intensity head and cylinder heat torch combo I picked up at Ace Hardware.
Now, if you can’t get enough heat from one of these torches, then you’ll need to find someone with an oxygen-settling torch which gets much hotter. Your local lawn mower shop should be able to help out.
How to Remove a Stuck Pulley from a Shaft (Step By Step)
Before you tackle the repair, you’ll want to get the lawn mower into a position where you can safely remove the stuck pulley. If you have a stuck pulley on a riding lawn mower, then I suggest you remove the cutting deck first. If you’re working on a push mower, I’d try to get it up on a workbench. I put together a DIY lawn mower lift table that really helps with these kinds of repairs.
The Steps on How to Remove a Stuck Lawn Mower Pulley
So, once you are ready and have your lawn mower in position, we can move on to the steps. Here’s what you’ll need to follow.
Brace the Blade/Drive Shaft
First, install your blade brace so that the blade can’t turn while you remove the pulley’s center bolt. For you guys trying to remove a pulley from a drive shaft, you’ll need to remove the flywheel guard and then attach a wrench to the top of the drive shaft.
Remove the Pulley’s Fixing
Once you have either the pulley spindle or driveshaft held in place so that it can’t turn, go ahead and remove the pulley fixing bolt using your socket wrench. If you happen to have a side-mounted fixing bolt, then you’ll not need to secure the spindle/pulley.
Drill Two Holes in the Stuck Pulley
If you want to reuse the pulley, then you need to be careful where you drill. You’ll want to drill close to the center and make sure you are not drilling through the pulley flanges where the belt would be located.
Doing this can give you problems when you go to install and drive the pulley later on. So, grab your drill and drill bit, then drill two holes through the pulley on the opposite side. Also, make sure the holes are big enough to take the bolts of the harmonic balancer puller.
Position the Harmonic Balancer Puller
Next, position the puller’s main center bolt over the pulley’s center spindle/driveshaft. Then thread the supplied bolt through the puller and then through the pulley.
Next, place a washer on the underside of the pulley onto the bolt and attach a nut. Replace this for both of the bolts that pass through the stuck pulley.
Take Up the Slack in the Harmonic Balancer Puller
Now that everything is attached, go ahead and tighten the center bolt of the harmonic balancer puller. I usually do this by hand. Once you have everything lined up and taken up the slack, you can grab your socket wrench.
Tighten the Harmonic Balancer Puller
Place your socket wrench on top of the center bolt of the harmonic balancer puller and begin to tighten. You’ll see the puller’s center bolt push down on the spindle/driveshaft and pull the pulley. Continue until the puller completely pulls the pulley from the spindle/driveshaft.
If That Doesn’t Work – Try This
There are a couple of situations where this might not work, and you might need to take a few extra steps. So, let’s take a look at how to remove a stuck pulley from a shaft if these steps didn’t work.
The Harmonic Puller Isn’t Long Enough
You could easily run into a situation where you tighten the puller all the way and run out of adjustment. The pulley was coming off, but now the puller isn’t big enough. Well, this is an easy fix. So, loosen the puller’s center bolt, then grab yourself a long bolt. You’ll probably find one in the pulley’s kit.
Take this bolt and lower it into the same hole the puller was pushing against where the spindle/driveshaft is. So, if you use a six-inch bolt in the hole, you’ll have extended the range of your puller by six inches. Then take up the slack in the puller and repeat the process from before.
I find that having a few good-sized bolts on hand really comes in handy when trying to remove the big pulleys from a driveshaft, as these pulleys tend to have much deeper pulley shafts.
The Harmonic Puller Isn’t Working
If you get a good harmonic balancer puller, then it’s going to have a lot of strength and will remove even the toughest of pulleys. But you’ll always find one that just won’t budge. This is usually how mine turn out.
So, this is when I turn up the heat and grab my high-intensity heat torch. What I do is slide the puller out of the way, then heat the center of the pulley and the spindle/driver shaft. If you’re new to the heat torch, then I’d try just to heat this area for a minute or two to start with, then retry the pulling process. I don’t recommend that you heat for much longer because you could end up causing some damage.
Finally, be careful where you are heating as these torches get extremely hot and will start to heat up those items close by. So, make sure you prep the area and watch where you’re pointing the torch. And don’t forget to have a fire extinguisher within reach.