Why Does My riding Mower Belt keeps coming off? Owning a mower has always come in handy for many homeowners. But if you have ever had a deck belt come off, then you know how annoying that gets. Sometimes, you can go on and on but the belt staying on your mower deck becomes rarer.
Before going into any action with it, check to ensure your belts are in good condition. You wouldn’t want to damage other parts of your mower. That’s because mower deck belts and drive belts are necessary functions of your mower. So, if one of the belts comes off your mower, your mower will fail to move or cut grass.
Keeping your belts and surrounding parts in good shape is essential. Features like the belt guides and brackets may get out of adjustment, or there’s damage to the brackets, bearings, or bushings.
Why your lawn mower deck belt keeps coming off
Before you work on your mower deck belt, this article provides explanations for why your belt may come off your mower.
1. You Have The Wrong Belt Installed
Perhaps you performed a DIY the last time you bought a deck belt, and it broke. You may have purchased the wrong match for your mower. Since there are tons of different deck belts in the market, it’s easier to buy the wrong one or get the wrong order.
If you ordered the wrong match for your lawn mower model, it will keep coming off, especially if it’s too big. That presents a problem when you mow your lawn at close intervals. However, it’s not an irredeemable issue. You can identify the proper deck belt for your mower and have the wrong one replaced.
Paying for another belt is frustrating, but the suitable replacement will stop coming off.
2. The Deck Belt is Worn or Wearing Out
Deck belts get worn over time, and that makes them come off more frequently. One reason is that the belt becomes thinner in the worn spots, so it slips off. Just like installing the wrong belts, you can get rid of worn ones and replace them with new deck belts.
If looking at options in the market, avoid cheap aftermarket deck belts, as they often wear quickly. More robust OEM models exist, so you can also check those out.
3. Damage to The Deck Belt Guide
Your mower comes with belt guides or belt keepers. They are small, rod-shaped posts designed to go around the pulleys. Also, some travel alongside the deck belts, depending on how long the belt must travel.
Like the belts, the belt guides can move out of place or get bent, especially when it has many slacks. That extra slack can cause the belt to hit the guide, bending the belt guide back toward the pulleys. When that happens, the deck belt jumps off the pulley and comes off your mower.
In addition, belt guides were never designed to touch the belt. Instead, they remain very close to the belt at about 1/8″ to 1/4″ away from the pulley. You can adjust the brackets by hitting them with a small hammer or vice grip to move them back into place.
4. Damaged Bearings in Pulleys or Cutter Housings
You will know that the bearings must be corrected when not running flat or straight. In most cases, the failed bearing is located in an idler pulley. The idler pulley has a sealed bearing, which means you have to replace the whole pulley with a bad bearing.
Not all pulled have a sealed bearing. However, you may come across drive pulleys or spindle housings with replaceable bearings. That means you can complete repairs with fewer parts.
Further, you can spot bearing failures in spindle housings when you grab the blades and rock back and forth. If you feel movement, replace the bearings in the cutter housings. These faults can cause your mower deck belt to come off.
5. Bent Belt Keeper
An essential part of the mower often overlooked is the belt keeper. Look at the deck; you will spot pin-like features alongside the pulleys. These belt keepers keep the belt in place and on the pulley. If one or more of the keepers get bent, a gap where the deck belt can go through will form.
When that happens, the deck belt will come off when raising and lowering the deck. Always check each belt keeper to see whether they are bent or out of shape, and adjust them accordingly. Also, make sure you don’t push them too close to the pulleys, as this can affect how they spin.
6. Debris
Ensure that the deck is free of debris. It’s common to have dry grass and debris forming under the lawn mower or on the deck. That often makes the tension pulley lack proper movement. As a result, the tension pulley can no longer keep proper tension on the belt.
Once the tensioner lacks mobility, then the belt will not stay tight. To avoid this scenario, keeping your lawn mower clean under the belt covers and beneath the mower body is important. The cleaner your mower is, it is easier to find failing parts before they eventually stop running.
Keeping your mower clean and in good condition will extend its lifespan and limit the chances of your mower deck belt coming off.
7. Oil or Rust on the Deck Belt
When oil leaks on your lawn mower, it may get to the deck belt. This can lead to the belt coming off. Your pulleys must remain clean of oil and rust so your belts are always in good shape.
In addition, oil is a petroleum product that can swell the deck belt the longer it remains. When a belt is covered with oil, it will begin to slip on the pulleys, which means it will have difficulty grabbing and building heat.
As for rust, that will make the lawn mower belt dry out and crack. When you spot cracks on your deck belt, it’s time to replace it as soon as you can.
8. Split Plate/Bracket Below Pulleys
Sometimes your mower deck belt keeps coming off, and most attention goes to the belt, the pulleys, and the pulley keepers. While these are the primary suspects, reserve judgment until you perform a check first.
You may have done an assessment and still see nothing wrong with them. Please take a closer look at the pulley bracket, the plate, and the other parts it is attached to.
The plate or bracket can usually split when the mower operates. That extra push can cause the pulleys to move and the deck belt to slip off. Thankfully, you can weld a broken split plate. You can also repair a bracket, but some situations will demand you replace them.
Conclusion
These are common issues associated with mower deck belts keep coming off. Without checking out the parts for such faults; you will have difficulty mowing your lawn to perfection. Moreover, keeping your mower clean and free from dirt and debris takes little.
Now that you know these issues and how to solve them, you can manage your mower better. You can rest easy maintaining your machine and nurturing your lawn.
