How to Fix Common Bobcat 334 Mini Excavator Problems?


Bobcat makes many different models of mini excavators, and one such model is Bobcat 334. It is one of the most popular mini excavator models out there. Comparing its size, this machine is really powerful and efficient. However, it can suffer from some problems in the long run.

There are many problems your excavator can suffer from. A few of the common problems the Bobcat 334 encounters are a defective hydraulic pump, a blocked case drain filter, and damaged oil seals. All these problems mostly occur when you do not regularly maintain your machine.

Thus, we have you covered if you are looking for solutions to common Bobcat 334 problems. Read below to know more.

What Are The Common Bobcat 334 Problems?

What Are The Common Bobcat 334 Problems

Bobcat 334 is a very efficient machine for your lawns, farms, and small to medium construction works. But, as time passes by, it starts to show some problems, which we will discuss below.

  • Faulty Hydraulic Pump 
  • Clogged Case Drain Filter
  • Damaged oil seals
  • Leaking Sprocket
  • Problematic Drive motor bearings

5 Easy Solutions For Bobcat 334 Problems  

5 Easy Solutions For Bobcat 334 Problems  

Bobcat 334 mini excavators can suffer from many problems. But, you do not need to worry as you can easily solve all these problems to ensure the perfect working of your machine. Down below, we will discuss all these solutions in detail.

1. Replace the Faulty Pump

Replace the Faulty Pump

If you notice your Bobcat 334 engine is making more noise than usual and performance is reduced along with engine overheating, the hydraulic pump is probably damaged.

Pump failure is most frequently caused by fluid contamination, which typically occurs when particles move throughout the system.

Additionally, the hydraulic pump may be prematurely destroyed if you utilize poor-quality hydraulic fluid.

If your pump gets damaged, unfortunately, you cannot repair the pump and will need to replace it. A hydraulic pump for Bobcat 334 can cost anywhere between $30-$50 with a labor cost of $120-$200.

You should also check your fuel filter after changing the pump to make sure it is not damaged and make sure to use recommended hydraulic fluids for your pump.

2. Clean or Replace the Case Drain Filter

Clean or Replace the Case Drain Filter

A clogged case drain filter is one of the most frequent issues with Bobcat 334 mini excavators. Hydraulic fluid cannot pass through a clogged case drain filter, which results in pressure buildup.

This pressure buildup may ultimately result in more significant issues, such as engine damage and occasionally blowing out your final drive motor. You should replace the clogged case drain filter asap; read below to learn how to replace it.

● Step 1: Locate the case drain filter

On a hydraulic drive motor, the case drain channel is the little line adjacent to the two in and out-lines. First, find that branch to find the case drain filter.

As you continue down the path, you will discover the case drain filter. The filter is made from aluminum and looks like a canister.

● Step 2: Open the filter

Open the filter

To prevent the loss of hydraulic fluid or contaminating the equipment, disconnect the filter first from the drain pipes and make sure to seal them.

● Step 3: Remove the case drain filter

Replace the case drain filter

Now you will see a hex nut at the bottom of the aluminum canister you just opened. Unscrew that hex nut and remove the internal bronze components inside of it.

Check the inside component and check its color; if the color looks black, rusty, or of any other color rather than bronze, you will need to replace the filter.

● Step 4: Replace the case drain filter

You can try cleaning and putting it back the same way, but the best option is to replace them. You can just buy a new case drain filter and put it back on the same way you just opened it up. A new case drain filter will cost between $25-$38.

3. Replace Damaged Oil Seals

Replace Damaged Oil Seals

Bobcat 334 mini excavator’s Oil seals in drive motors are most prone to damage. They should be changed on time as if you do not change them they will get damaged.

The seals will start to seep fluid, which will damage performance and cause essential pieces to wear out more quickly.

It is fairly easy to change damaged oil leaks, and new oil seals will cost only around $5 per piece. Read the steps below to know how you can replace them by yourself.

● Step 1: Open your drive motor

Open your drive motor

Open up your drive motor using a screwdriver and access the old oil seals. You will see washers, and you will also need to unscrew the washers before removing the oil seals.

● Step 2: Remove the seals

Now remove the old damaged oil seals using a seal removal tool. Clean the outside area properly to make sure that news seals are not contaminated in any way.

● Step 3: Insert new seals

After removing the old seals, insert new seals in the same place in the same way as you have removed the old ones. Put back the washers and close the drive motor.

4. Replace the Floating Seals

Replace the Floating Seals

When the floating seals get damaged or contaminated, this can be the main reason for leaking sprockets in your Bobcat 334.

Gear oil may leak from damaged floating seals, allowing dirt to enter. Dirt in your final drive results in expensive repairs and significant gear, spindle, and bushing problems.

Changing floating seals by yourself is a bit complicated as it requires you to have a proper idea of the internals of your mini excavators.

You surely do not want to cause more damage to your machine while trying to replace the floating seals by yourself.

So, the best idea is to visit a professional service center, which can be around $100-$300, depending on the range of damage and the area you live in.

5. Remove the Old Bearings

Remove the Old Bearings

Your Bobcat 334 begins to fail as you use it too regularly. The drive motor’s bearing also degrades quickly.

Remember that a damaged primary bearing will put a strain on the final drive motor, necessitating either the replacement of the motor’s complete or its final drive component.

Just like floating seal replacement, drive motor bearings replacement also is a complicated process, and it is better to visit a service center.

Replacement bearings come in various prices and can cost between $80-$100, including service charges.

Frequently Asked Questions (FAQs)

This section is all about FAQs about the common problems of Bobcat 334 mini excavators. Make sure to read below as it will further clear out all of your confusion regarding our discussions today.

How long should a hydraulic pump of Bobcat 334 last?

A Bobcat 334 pump with a duty ratio of 70% or fewer, spinning at a 1300 rotation speed, and fresh oil will probably endure for more than 20,000 hours. But while operating at 1,800 rpm with a 90% capacity and good quality of oil, the lifespan is just about 10,000 hrs.

Why is my Bobcat 334 engine making noise?

The bobcat 334 engine is very reliable. But it can be damaged for various reasons like clogged fuel filters which contaminate fuel and prevent the regular flow of fuel to the engine. It can also be caused due to improper lubrication in your hydraulic system.

Is Bobcat 334 a good excavator?

Bobcat 334 is a very durable excavator intended for both home and commercial uses. It comes with an auxiliary hydraulic system which gives more user-friendly operation while using this machine.
Under proper maintenance, the Bobcat 334 will run perfectly for many years, even under heavy loads.

Why is black smoke coming out from Bobcat 334?

If you see excessive black smoke from Bobcat 334, that means your fuel inside the fuel tank is contaminated, or your fuel filter is clogged. You will need to clean your fuel and refill the tank. Also, make sure to change your fuel filter if it’s clogged.


No Mini excavator comes without problems; the same applies to the Bobcat 334. By creating small, adaptable, and simple-to-maintain designs, Bobcat has repeatedly overperformed most of its competitors.

Most of the problems we’ve covered above may be avoided if you do routine maintenance on your excavator. This machine’s power is more than enough to be used in lawns, farms, and small to medium construction sites.

But, if you want this machine to keep performing perfectly even after years, always change the oil seals and filters on a regular basis. If you decide to troubleshoot the problems by yourself, make sure to have a proper idea of the internals of Bobcat 334.

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