How Do You Put Hydraulic Fluid In A Zero Turn Mower?

Having a zero-turn mower is all nice and convenient until you have to care for it properly. Then, like any other mower, for your zero-turn mower to give you the best results, you have to make sure you’re giving it what it needs. One of the ways to make sure that your zero-turn mower stays as brand new as possible is to ensure that the hydraulic fluid is in good condition. 

The hydraulic fluid is the medium through which power transmits in hydraulic machinery such as your zero-turn mower. The short answer is it should be changed after the first 75 hours of operation and then every 400 hours of usage afterward. However, every machine is different, so refer to the owner’s manual for guidance. 

Hydraulic oil is the lifeblood of the entire hydraulic system. Thus it must be in good working order. So, how do you put hydraulic fluid in a zero-turn mower? And when do you need to change it? We answer both questions in detail in this article. 

How Often Should You Change the Hydraulic Fluid?

Most recommendations say that you need to change it depending on the service hours. It’s said to be ideal to change it after the first 75 hours of operation, then change it again after every 400 hours of usage. 

The manufacturer’s user manual should advise you with regard to how often you should change your oil. So, make sure you read it to gain some background information on your mower brand before moving on with further steps.

If you can’t tell when your mower needs a change of oil, check for any of the common hydraulic equipment mistakes.

How to Put Hydraulic Fluid in Your Zero-Turn?

Whether or not this is your first time changing the hydraulic fluid in your zero-turn mower, make sure you have a basic understanding of hydraulic systems. This is to ensure that you wouldn’t accidentally damage your machine.

To do so, you can check the manufacturer’s guide first. They usually have a step-by-step guide on how to change your hydraulic fluid, so read it and get familiar with your machine. 

Before you start, there are some things that you’ll need, including:

  1. A compatible oil for your mower (refer to the manufacturer’s guide)
  2. Two jack stands
  3. A basin or a big pan to drain the oil fluid
  4. A compatible oil filter
  5. An adjustable wrench
  6. Gloves and safety goggles for protection

Step 1: Prepare Your Zero-Turn

To prepare your zero-turn mower, start by keeping it on level ground. Afterward, make sure that the power is off entirely and take the key out of the ignition. This will stop all engine parts and let the mower cool down before changing the oil.

Now that it’s off get the jack stands and use them to heave the mower off the ground. Put them on the right and left of the rear wheel and lift your mower from the backside.

Step 2: Get the Pan

Now it’s time to use it, whether it’s a pan, a large bucket, or a basin. First, locate the drain plug after your mower is raised off the ground and put the pan underneath it. 

You would usually find the drain plug right under the hydraulic fluid reservoir.

Step 3: Drain the Oil

Remove the reservoir’s lid to help the oil flow into the container underneath it. Leave it for 10 to 15 minutes to ensure that all the old, sluggish oil is completely drained.

To completely drain the oil, you will need to remove the drain plug completely. Then, make sure you clean any excess oil on the cap with clean water and a clean rag.

Ensure you wipe out the area around the filters to help prevent dirt or other contaminants from entering the hydraulic system.

Step 4: Remove the Hydraulic Filter

After making sure all is clean, you can now remove the hydraulic filter. You’re going to find it in front of your hydraulic reservoir. Find it, unscrew it, and then move on to the next step.

Step 5: Replace the Oil Filter

To install the new oil filter, start by putting some oil on the gasket to lubricate it. Hold the replacement filter upright before screwing it onto the oil filter adapter to avoid spillage.

Make sure you don’t over-tighten the oil filter, as this can cause the threads to cut out.

Step 6: Add the New Oil

Place a funnel and add the fresh hydraulic oil into the reservoir. Pour it gradually and make sure it reaches the proper level. Make sure you clean any spillages after adding the oil. Then, replace the cap on the reservoir and tighten it correctly.

Step 7: Turn on the Engine

The last step in changing your mower’s oil is to turn on the engine and keep it on for about 30 seconds. This would purge air inside the lines or the oil filter. 

This purging is critical for a zero-turn mower engine since it aids in the removal of impurities and prepares the equipment for future usage.

After turning off your mower, check the oil level once more to make sure that the oil is not leaking or flowing out.

Why Do You Need to Change the Hydraulic Fluid?

You’re now an expert in changing the hydraulic fluid in your zero-turn mower, but do you know why you need to change it?

Well, hydraulic fluid is a major component that affects the health of your mower. If it goes bad, your mower won’t run efficiently, and its internal parts might get damaged. 

In turn, two factors affect the health of your hydraulic fluid: the degradation of the base oil and the depletion of the additive package.

Since there are so many diverse reasons that could affect the rate at which the oil degrades or the additive packages get used up, changing the hydraulic fluid only based on the service hours isn’t the best way to go. 

With that in mind, make sure you don’t change your hydraulic fluid in your zero-turn mower unless you’re confident that this is the correct timing for an oil change. Then, you can avoid wasting money and effort getting rid of the oil that doesn’t need to be changed.

However, sometimes the oil in the machine won’t provide the protection you think it will. This is because your hydraulic fluid depends not only on the service hours but also on other factors that either help it remain in tip-top condition or damage. 

These factors that affect the health of your hydraulic fluid include:

  1. Hours in service
  2. Operating temperatures (running too hot would result in the damage to your hydraulic fluid as well as affect the health of your zero-turn mower)
  3. Water and air contamination levels

The hydraulic fluid doesn’t just work as a lubricant; it also helps power the whole mower, so it’s a must to keep it healthy for the best mowing quality possible. 


Changing your zero-turn mower’s hydraulic oil can seem tricky, but in reality, it only requires some background information and steady, confident hands. 

If you’re not sure of a particular step, always refer to the user’s guide to avoid any accident.

Understanding your zero-turn mower and knowing all the tips and tricks regarding its operation would help you save a lot of money and provide you with the best mowing experience.

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