The undercarriage components of a bulldozer are the key parts that allow the dozer to move, steer and track properly during operation. These components include the track chain, the track guards or rollers, the sprocket and idler wheels as well as the center and pin joints. An important part of the undercarriage are the bucket pin, bucket teeth and adapter bracket. Maintaining and inspecting these parts regularly can help ensure efficiency and longevity of your dozer.


Bucket Pins and Adapter Bracket

  • The bucket pins are cylindrical steel shafts that connect the bucket to the dozer’s lift arms. They are placed into holes in the adapter brackets that are welded to the bottom of the bucket. The pins are usually bolted to the arms using retaining nuts and cotter pins. The adapter bracket provides a solid connection point for the pins to attach to the bucket. Over time, the pins and bushings inside the adapter bracket can become worn leading to sloppy bucket attachment and damage. Check the pins regularly for signs of excessive wear including elongation, bending and cracks. Replace as needed.

Bucket Teeth

  • The teeth attached to the cutting edge of the bucket are an important part of the dozer’s performance. The teeth dig into the material being pushed and help retain it inside the bucket. As the material builds up, the teeth eventually wear down and need replacing. Inspect the teeth frequently for wear, damage or loose fasteners. Keep a stock of replacement teeth on hand to avoid downtime. The design of the tooth mounting varies between dozer models but usually consists of replaceable shrouds and tips that are bolted to brackets welded to the bucket.

Track Chain

  • The track chain is the assembly of interconnected links and bushings that forms the continuous belt which allows the dozer to move. It runs around the sprocket, idlers and rollers. The cleated or grousered bars attached to the links provide traction and help steer the machine. Make sure the track is tensioned properly according to the manufacturer specifications. Check regularly for damaged, broken or missing links and rollers. Replace individual links as needed to maintain an even tension throughout the chain.

Idler Wheels and Sprocket

  • The idler wheels and sprocket are mounted on either end of the track chain. The sprocket engages the chain and is driven by the transmission to propel the dozer. The idler wheels provide tension and alignment to the track around the roller frame. Both the sprocket and idler wheels have sealed bearings that require periodic lubrication and inspection for wear. Check the sprocket teeth regularly for damage or excessive wear. Replace sprocket and idler wheel assemblies as needed.

Rollers and Track Guards

  • The rollers provide support and guidance to the track as it circulates through the undercarriage. The track guards cover and protect the rollers from debris and material. Inspect the rollers and guards frequently for damage, missing bolts and bushings. Replace any damaged or worn components. The rollers should turn and rotate freely on their shafts. Clean and lubricate them regularly.

Center Pin Joints

  • The center pin joints connect the two sections of the track together, forming an endless loop. They consist of cylindrical steel pins that are usually bolted together using retainers. Check the pin joints regularly for excessive play, damaged bushings, cracked pins and loose or missing fasteners. Replace pin joints that show significant wear to avoid track damage and downtime.