4 Gravely Zero Turn Mower Hydraulic Problems

Gravely, like John Deere, is one of the more popular lawn mower brands. As widespread as they are, some problems are still associated with Gravely’s, especially the hydraulic system of the Zero turn mower. 

Some signs that may indicate an issue with your hydraulic system are higher levels of emission, faulty or weak hydrostatic transmission, and constant breakdowns. 

When these problems arise, it becomes difficult for the lawn mower to work properly. That is why they need to be resolved as soon as possible. In this post, I look at these problems and their solutions.

Problem 1: Large Volume of Emission

One of the problems associated with the Gravely Zero Turn mowers hydraulic system is high emission levels. A clogged air filter is a significant cause of Gravely churning out a lot of smoke. The air filter is a guard to prevent impurities from getting into the engine or transmission. It regulates the amount of air that gets into the machine.

However, the longer the air filter works, the more clogged it gets until it reaches a point where the amount of air in the mower gets limited. That’s not the only thing that a clogged air filter causes. It also burns up a lot of oil and reduces oil levels which in turn increases the amount of smoke it produces. 

When you notice your mower is giving out a lot of smoke, you must do something about it quickly. Massive emissions are often precursors for more extensive problems in the mower, like engine damage. I recommend cleaning or changing your air filter as soon as you notice your Gravely’s emission levels rising.

Problem 2: Hydrostatic Transmission Troubles

One of the significant reasons for hydrostatic transmission issues is when there’s a more substantial percentage of air than oil in the transmission. Air in your hydrostatic transmission is called cavitation.

When cavitation occurs, your mower will have trouble starting because the transmission cannot provide enough power for the mower’s engine to work efficiently. Here are some of the things you should do if you notice an issue with your transmission.

Check The Mower’s Channels and Pipes for Leaks

The Gravely Zero Turn mowers use a hydraulic system, meaning it needs a vacuum to generate enough hydraulic or hydrostatic energy for the engine to work correctly. When there’s a leak in one of the channels or pipes, it is not only oil that leaks out. Air also gets in the hydraulic system disrupting the vacuum and reducing the power produced.

When you notice that your hydrostatic transmission isn’t working correctly, leaks are the first things to check for. Change the damaged pipe and top off oil levels if you notice any.

Ensure The Oil Levels Are at the Recommended Level

Another thing that might be causing hydrostatic transmission problems, which will lead to your Gravely mowers having hydraulic problems, is unacceptable oil levels. The manufacturers have a recommended oil level. Anything less or more than that level will lead to hydraulic issues.

Go to the hydraulic fluid’s container to check the recommended oil level. Usually, some lines act as a meter for the oil level. One of the lines is the maximum level. Another is the minimum level. 

The mower won’t work correctly if the oil level is lower than recommended. The same thing happens when the oil is higher than the recommended level. So, if the oil is lower, add more oil. If it is higher, bleed some oil until it reaches the recommended level.

Inspect The Air Filter For Impurities

The air filter’s job is to block impurities like sand, grass, and dust from getting into vital parts of the mower. One such part is the transmission. 

Check the air filter regularly to ensure it’s doing its job correctly and impurities aren’t getting in to block pipes or damage the transmission. If you notice a contaminated air filter, it means it cannot do its job correctly. I recommend that you change it if this is the case.

Now that the leaks are all plugged in. The next thing to do is get rid of the air already in the hydrostatic transmission. Getting rid of the air is relatively easy. All you have to do is follow these easy steps.

● Move your Gravely to level ground, ensure you engage the parking brake, and raise the back of the mower.

● After confirming that the oil is at the recommended level, remove the transmission. Please don’t fret. Gravely already has a safe way to do this in their owner’s manual.

● Still, in that raised position, get someone into the mower and start the engine. You could also do it yourself, but making it a two-person operation is better so one person can observe while the other is in the operator’s seat.

● While the mower’s engine is still running, let the person in the operator’s seat move the throttle from rest to a slow position. Simultaneously, move the control level to the neutral position before taking the foot of the clutch.

● After a few seconds, move the motion control levers to the most forward position and hold it there for at least five seconds. 

● Repeat the above step in the opposite direction (most reverse position), and hold it there for at least five seconds.

● Ensure that you repeat the forward and backward movement of the motion control levers three to five times. As the levers move forward and back, it expunges all the air in the mower’s system.

● When you are sure the air is out, put the levers back in neutral, shut off the engine, put back the transmission, and lower the mower.

Problem 3: Mower Breaks Down During Operation

Many mower owners overlook the air filter’s importance to their mowers’ overall health. A faulty air filter doesn’t only increase emission levels and causes transmission problems. It could also lead to the mower engine shutting down while in operation.

The sign of a good air filter is that you should be able to see through it when you put it against a light source. Once you clean it and still can’t see through, I recommend changing it. 

Another reason your Gravely Zero turn might turn off while working is low-quality fuel. Harmful fuel damages the fuel pump, corrodes the fuel tank and leads to wear along the fuel line. The best way to prevent this is to always use quality gas in your tank.

Problem 4: Gravely Zero Turn Mower Weak on One Side

You might have noticed that there are times when your mower is weak on one side, and no matter what you do, the mower doesn’t correct itself. The weakness also makes it difficult for it to gain traction while moving.

A significant reason for this might be a dragging brake. If one of your brake drums or pads doesn’t fully disengage, then the mower will be weak on that side. You should check the brakes to make sure it is fully cleared. Engaging both throttles simultaneously will also lead to the mower being weak on one side. 

Frequently Asked Questions:

What kind of hydraulic fluid does a Gravely zero turn mower use?

Gravely zero turn mowers perform well with Gravely’s own OEM 15W50 synthetic oil.

How often should you change hydrostatic transmission fluid?

It is typically recommended to change the hydrostatic transmission fluid every 250 hours, or once a year – whichever comes first. However, it is always best to check your owner’s manual for specific recommendations from the manufacturer.

Final Thoughts

Early detection of Gravely Zero Turn hydraulic problems lawn mowers is essential to prevent even greater damage. Signs like a smoky exhaust or non-linear movement might signify a bigger problem at hand.

Pay attention and resolve these as soon as they arise, and your Gravely zero turn will serve you for a long time.