Worn Excavator Track Chain? When to Replace It and What to Order

The track keeps needing adjustment, the pins have play, or a link has cracked. Before you order, check how worn the chain is, decide between a single link and a complete chain, and look at the sprockets.

The Track Chain range at PartsForMachines covers 2,390 track chains and chain links for Caterpillar, Komatsu, Hitachi, JCB and other tracked machines.

How Do I Know When a Track Chain Needs Replacing?

Replace it when the wear reaches the machine maker’s limits, and measure it rather than judge by eye. As the pins and bushes wear inside, the distance between pin centres (the pitch) grows. The chain effectively stretches and the track runs loose, so it keeps needing adjustment.

A stretched chain also stops the bushes meeting the sprocket teeth in the right spot, which speeds wear on both. To put a figure on it, measure the pitch and compare it with your machine’s service information, or have an undercarriage specialist measure it.

Can I Replace One Link, or Do I Need a Whole Chain?

Fit a single link if one link is cracked or broken and the rest of the chain is within its wear limits. If the pins and bushes are worn all along the chain, one new link won’t bring back the pitch, so fit a complete chain.

The range splits into about 1,400 complete chains and nearly 1,000 single links. Most links are listed by machine, and some also name the pin they suit: slide-in, 38mm slide-in or press fit. Match that as well as the model, for example with a single link to suit a slide-in pin for the JCB 131X.

Should I Change the Sprockets at the Same Time?

Usually, yes, if the chain is worn out, because chain and sprockets wear as a pair. As the chain’s pitch grows, the sprocket’s effectively shrinks, and the mismatch makes the bushes slide across the teeth, wearing both faster.

A new sprocket on a worn chain keeps that mismatch, so it won’t last as long as the old one. A new chain on worn sprockets is mismatched too. If the chain is only lightly worn, measure its pitch before fitting new sprockets alone. When you order the chain, ask our team about sprockets for the same machine.

How Do I Find the Right Chain for My Machine?

Start with the original part number from the old chain or the parts book. About 170 chains are listed by the original number they replace, such as the track chain for Komatsu 208-32-00311. Type your number into our site search to find a match quickly.

Without a number, use the full model, including any suffix such as L, LC or SR, because a suffix can change the chain. Then count the links on the old chain. Some chains show a link count, such as the 50-link Liebherr R924 Compact chain; for others, give our team the number. Check the new chain’s details against the old one before you order.

What Should I Check Before I Order?

• the original part number, from the old chain or the parts book
• the full machine model, including any suffix such as L, LC or SR, and the serial number
• the number of links on the old chain
• for a single link, the pin it suits: slide-in, 38mm slide-in or press fit
• the wear on the sprockets, rollers and idlers

Browse the Track Chain range, or contact the PartsForMachines team by WhatsApp, telephone or email with the machine model, serial number and any part number from the old chain. A photo of the old link and its pin helps too.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

What does “% worn” mean on a used machine’s undercarriage?

It is how much of a part’s wear life has gone, as a percentage, so 70% worn leaves roughly 30% of its life. Each part can carry its own figure, so ask which parts were measured and whether the number means worn or remaining.

My steel-tracked digger keeps throwing a track: is the chain to blame?

It can be. A worn chain stretches and runs loose, and a loose track can come off. Check and set the tension first. If the slack keeps coming back, measure the chain’s wear.

Does running the tracks tight rob power or wear the chain?

It can do both. A tight track adds load, which speeds wear on the bushes, sprocket teeth, idlers and rollers, and the machine needs more power and fuel for the same work. Set the sag to the operator’s manual, checked on site.

What is the master pin, and where do I split the chain?

The master pin, or master link, is the joint designed for splitting the track, so start there. Press-fit pins typically need a large hydraulic track press. When replacing a link, match its pin type, such as the press-fit link for the Caterpillar 325.

How can I tell if my chain is sealed and lubricated?

Check the parts book or part number. A sealed and lubricated chain holds oil in each pin behind seals; if a seal fails, that joint can run dry. Separately, most of our chains and links have polyurethane seals to keep grit out.

Will wider track pads wear the chain faster?

They can. In the wrong conditions, wide shoes can damage the chain’s links, pins and bushes, so use the narrowest shoe that still gives the flotation you need.

What else should I check while the chain is off?

Check the top and bottom rollers and the idlers, because the undercarriage wears as a system. For the Caterpillar 312C there is a combo pack with track chains, nuts and bolts and carrier rollers.

Does the L version of a machine take a different chain?

It can. The Caterpillar 312C takes a 43L chain, while the track chain for the 312C L is a 46L, and the 312B, D and E split the same way. Don’t go by the base model alone; match the full designation.

Should I have the pins and bushes turned instead of buying new chains?

Sometimes. Turning them 180 degrees brings fresh wear surfaces into use and can give the chain a second life. Have the whole undercarriage measured first, and ask an undercarriage specialist whether turning or a new chain makes more sense.