How To Replace Rollers, Sprocket & Idlers On Your Undercarriage

How To Replace Rollers, Sprockets, and Idlers On Your Undercarriage

Removing an undercarriage can take a long time, and it should be done systematically with the correct tools. There are variations on removing undercarriages depending on the manufacturer, model and type of undercarriage. This blog will guide people who have no special training or tools on how to remove rollers, idlers and sprockets.

In order to remove these components, the tracks must first be removed. Here are the basic tools you will need to complete the work:

  • Impact gun/breaker bar
  • Hammer
  • Winch, come along or a chain

Replacing Rollers

Remove guards from around the rollers by removing the bolts that secure them to the undercarriage. Remove the rollers in the same way.

Replacing Idlers

Tracks don’t need to be fully removed to change the front idler. You do have to jack up the machine, find the master link and separate the two components of the master link and then pull the top of the track toward the rear of the machine to give you access to the idler.

Then use an impact gun/breaker bar to remove the bolts keeping the idler in place. Then pull the idler forward, wiggling as necessary.

Replacing Sprockets

To remove the sprockets, again, you don’t need to remove the tracks. If you are changing out just the sprockets and don’t plan on fully removing the tracks, use an impact gun/breaker bar to loosen the bolts on the sprocket enough they can be hand turned. (Many dozers come equipped with a guard that protects the sprocket. As a result, only the bolts on the upper part of the sprocket are accessible with a tool.)

Then you need to jack up the dozer. Just backing up the dozer onto some blocks will suffice. Line up the blocks under the roller directly in front of the sprocket. Also, make sure the bolts that were inaccessible before are accessible now. Then put the dozer blade down so that it lifts the front part of the tracks off the ground.

Fasten one side of a come along to the track adjuster pinion (near the front roller) and attach the other side to the track chain at the sprocket.

Use a wrench to loosen the lock nut (also called a jam nut) located near the front roller. Then remove the bolt. This is where the grease exits the undercarriage. Slowly push the track adjuster in a few clicks at a time and then remove the grease that has come out. Repeat this process until the track adjuster is pushed in all the way and all the grease is removed.

Then you need to raise the track off the sprocket. You can use one of a variety of devices to achieve this. You can use chains or a come along to fasten it to upper parts of the dozer to achieve lift or use a lifting device.

Remove all the bolts from the sprocket. The bolts on the upper part of the sprocket will need an impact gun or breaker bar while the sprockets on the lower part should be able to be hand turned.

Caution: when removing the last bolt, the sprocket may pop off. Alternatively, if the sprocket is not easily removed by hand, hit it a few times with a hammer to loosen it.

Once the sprocket is loose, pull the sprocket away from the dozer and up while someone else grabs the tracks at the rear and pulls backward. You may need to wiggle the tracks to separate the sprocket from the tracks.


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Searching For Heavy Equipment Parts?

We specialize in undercarriage and complete components for excavators, dozers, crawler loaders, and wheel loaders.