How Do You Replace Tracks on a Bobcat Mini Excavator?

Replacing a track on a Bobcat mini excavator is decided before the machine goes up on the jack. The belt comes off in an hour; what decides whether the job is worth doing is the inspection that happens first - because a new track fitted onto a hooked sprocket or a flat-spotted roller will wear out early, and the second set costs more than the first. This guide covers the whole job, in the order it should be done.

Last updated: October 5, 2026

It covers what to check before anything is dismantled, the tools and safety setup, how tension is released, how the old belt comes off and the new one goes on, how tension is set correctly, and which parts around the track decide how long the replacement lasts.

What to check before the track comes off

Do all of this with the old track still on, because the wear it has left behind is the evidence you need.

Record the fitment. Write down the width, pitch and link count marked on the track, plus any part number. For most of this family the belt is a 300x52.5Nx80, which this catalogue lists for the 231, 329, 331, 334, 425, 428, E26 and E32 - but read the marking on your own machine, because other E-series models use the same width and pitch with a different link count.

Judge the track itself. A belt is finished when it has cracks running to the cord, lugs torn away to the carcass, exposed steel cord, or sag it will not hold even when tensioned. Slippage under load and frequent de-tracking are the other two signs, and both usually point at something other than the belt.

Inspect the parts it runs on. Sprocket teeth that are hooked or rounded will climb a new belt and stretch it out of pitch; an idler face worn unevenly means the track has been running off centre; rollers with flat spots, free play or weeping seals are finished and will wear the new belt unevenly. This is the inspection that decides whether the job is a track change or an undercarriage job.

Tools and safety setup

The tool list is short: a hydraulic jack rated well above the machine's weight, axle stands or heavy blocking, a track tension gauge, two pry bars, a sledgehammer and punch for the master link, a grease gun, a socket set for the idler and roller hardware, and gloves and eye protection. A half-inch impact wrench makes the mounting hardware much quicker, but the job is doable without one.

The safety setup matters more than the tools. Park on firm, level ground, lower the attachment, set the parking brake and chock the machine so it cannot roll. Support the raised side on stands rather than on the jack alone. Block the track before you break the master link, because a slack track is heavy and moves when the link releases. And when you release tension, never stand in the discharge path of the grease fitting - the grease comes out under pressure, and the fitting should be opened slowly with your hand to one side.

Releasing tension

Tension on these machines is held by a grease-filled cylinder that pushes the idler forward. Clean around the grease fitting first, because grit forced into the cylinder is what kills tensioners, then open the fitting slowly and let the grease escape until the belt goes slack. Release the hydraulic pressure first, per the machine's manual, so nothing can move under stored pressure while your hands are inside the frame.

Once the track is slack, block it, then drive the master link pin out with the punch and sledgehammer and walk the belt off the sprocket and idler by rotating the wheels by hand a little at a time. Lift the side of the machine at the track frame and work the belt off the rollers with the pry bars in short sections - a track fought off in one pull takes a roller or an idler with it.

Fitting the new track and setting tension

Offer the new belt over the sprocket first, then feed it around the idler and onto the rollers, keeping the direction marking correct and the belt square to the frame. Join the master link, applying anti-seize compound to the pin threads as you reassemble. Then run the machine a short distance and watch the belt track straight before it goes back to work.

Tension is set with the grease gun. The target figure is specific to your machine and belongs in the manual; the method is the same everywhere: lift the machine so the track hangs clear, measure the sag at the mid-point between the sprocket and the idler at the height the manual specifies, and check the other side. The two tracks rarely share a tension, and a machine running one tight and one loose steers badly and wears the tighter one first. Re-check after the first hours of work, because a new belt stretches while it beds in - and if the track starts slapping or the machine drifts, that is a tension or alignment symptom rather than a track fault, as why an excavator track sags sets out.

The parts that decide whether the new track lasts

A track is one component of an assembly, and this is where the job usually turns into more than a track change.

The drive sprocket. If the teeth are hooked, replace the sprocket in the same job. The work means releasing tension, removing the track, unbolting the worn sprocket, checking the final drive flange for wear or distortion, then fitting and torquing the new one before the track goes back on - and it is the flange check and the sprocket-to-chain engagement that decide whether the job succeeds. A sprocket for the smaller models in this family is listed as sprocket 6813372 for Bobcat 231, 325, 329, 331 and 334 machines.

The front idler. A worn idler lets the track run off centre, so it belongs in the same inspection. Unbolt the old assembly, clean the mounting area, fit the replacement, and re-tension; verify the machine's serial number and undercarriage configuration first, because idlers differ across the range. Two examples from this catalogue show the pattern: front idler 6815125 for Bobcat 337, 341 and 435 machines, and front idler 6693237 for the T140, T180, T190, T200, T250, T300 and T320 loaders.

The carrier rollers. A worn top roller lets the upper run sag onto the frame, which shows up as noise, vibration and accelerated undercarriage wear. The check is quick with the track off, and a replacement such as carrier roller 7013581 for Bobcat 331, 337 and 341 machines belongs in the same order if it is due.

The track rollers. Turn each one by hand; flat spots, roughness or free play mean the bearing has failed, and a failed roller transfers its load into the belt. Where they are due, a set is cheaper than three separate jobs - an example being track roller 7013577 for Bobcat E45, E50 and E55 machines.

Model notes worth knowing before you start

Three practical differences come up across this family. On the MT-series walk-behind loaders, access is tighter and the machine has to be lifted higher to clear the belt, so the blocking matters more; the sequence is otherwise the same. On the 331 and the earlier E-series, the same 300x52.5Nx80 belt covers several models, but the sprocket and idler configurations differ between them, so confirm the numbers rather than assuming the track fitment implies the rest. And on any of these machines, if you are doing the job for the first time, the walk-through for replacing the tracks on a Bobcat 331 shows the order of work on a small machine without the added complexity of a bigger undercarriage.

Where the machine's work involves softer or more abrasive ground than it was originally specified for, the material question is worth revisiting at the same time: how rubber and steel track construction differs explains where a rubber belt stops being the right answer.

What to have in writing when you order

Four items: the part-number cross-reference naming your machine, model and serial number against the belt; the specification as supplied - cord construction and insert count, tread pattern and depth, compound; the warranty terms as a period plus an operating-hours cap, whichever comes first, with freight responsibility named; and the stock position with a delivery date, because the machine stands still until the part arrives.

This article is part of the rubber tracks guide, which covers how the size code works, tread patterns, compounds and buying a set in Canada.

FAQs

How long does it take to replace a track on a Bobcat mini excavator?

The swap itself is a few hours with the right tools and the machine properly supported; the undercarriage inspection around it takes the same afternoon. What stretches the job is discovering that the sprocket or idler is also due, which is why checking first is worth the time.

What tools do I need?

A jack and stands or blocking, a tension gauge, two pry bars, a sledgehammer and punch for the master link, a grease gun, a socket set, and gloves and eye protection. An impact wrench speeds up the mounting hardware.

How tight should the tracks be?

Exactly the figure in the machine's manual, measured where the manual says to measure it, at the stated height and over the stated number of links, with the machine lifted so the track hangs clear. Check both sides.

Why does the new track run off to one side?

Usually alignment or a worn component rather than the belt: an idler running out of line, a sprocket whose teeth are hooked, or a roller with flat spots. Stop and check those before running the machine, because a misaligned belt wears its shoulder quickly.

Do the tracks have to be replaced in pairs?

If both have run the same hours on the same ground, yes - the machine otherwise steers against the older belt and wears the new one faster. A single replacement is reasonable when one belt has been damaged early on an otherwise sound set.