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Installing a Face Seal on a Final Drive Motor

Installing a Face Seal on a Final Drive Motor

Posted by Jim Strong on Mar 6th 2021

In this Shop Talk Blog post, we'll be going over the steps for installing a face seal using a Bobcat T300 as an example, although the general steps can apply to face seals in general. We'll also look at the same process for CAT machines.

Here are a few other Shop Talk Blog posts you might find helpful:

Quick Review on Floating Face Seals

The purpose of a face seal is (also known as a duo cone seal or the main seal) is located where the hub and axle come together. Each seal has a precision ground metal ring with a rubber ring. Face seals are probably exposed to more wear and tear than any other seal on your final drive motor. And when they fail, they don't only leak but they'll allow the dust, grit, sand, and dirt found at your worksites into your drive motor. 

Basic Steps for Installing a Bobcat Final Drive Face Seal

Prior to Installation

There are some things you need to do before starting the installation process:

  • Make sure your have a clean work area
  • Separate the axle and the hub so that you can access the face seal
  • Make sure the bearing race is already installed (it cannot be installed after installing the seal)
  • Wipe the housing clean with a lint free cloth where the rubber portion of the seal will be installed (it should be free of oil, grease, dust, metal chips, etc.)
  • Check the seal for any signs of damage
  • Wipe the seal clean of with a lint free cloth
  • Find a plastic tool with a blunt edge, because a metal tool WILL damage the rubber on the seal

Installation of the Face Seal

Here are the general steps to follow for installing the face seal on your final drive motor

  1. Place face seal on top
  2. Again, using the blunt edge of the plastic tool, carefully fold the bottom rubber lip in smoothly under the retaining lip on the housing may get a little bit of excess that wrinkles up
  3. This folding process should be done a little at a time around both sides
  4. Once this is done, take the flat, blunt edge of the tool and make through the rubber is smooth with no humps or wrinkles
  5. Next, push on the top of the seal with your hands to make sure the rubber is set in and the seal is not going to come out

At this point, the axle face seal can be installed following the same basic process.

Notes on Installing CAT Final Drive Face Seals

For Caterpillar machines, the face seals are called duo cone seals and the rubber portion of the seal is referred to as a toric ring because of its cross-section. In this video, they review how to install seals on larger CAT machines. You'll notice the seals are also larger and require a special type of tool for installation along with a rubber mallet. You'll also notice how the video emphasizes the importance of keeping everything clean!


Eventually, your face seals will eventually wear out -- but if you catch them early, you can replace them and prevent thousands of dollars of damage. You can prolong their useful life by keeping the area around your drive motors free of debris using a pressure washer or just a plain hose to rinse them off regularly.


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