Bottom Roller Leaking, Seized or Worn? Replace and Match It

Oil streaking down a roller, a roller that has stopped turning, or a tread worn well down: a failing bottom roller can lead to bigger undercarriage repairs if it is left. The cure is usually a new roller, matched by machine, part number and flange type.

PartsForMachines lists more than 1,600 bottom rollers for excavators and other tracked machines. Here is what each sign means and how to order the right one.

Oil Weeping From a Bottom Roller: Is the Seal Finished?

Fresh oil running from a roller often means a failed seal, and that roller is living on borrowed time. Bottom rollers run in oil, so once a seal lets go the level drops and the bearings lose their lubrication. Left alone, that can end in a seized roller or a bigger failure.

Before you condemn it, wipe the roller clean, track the machine for a while and look again. Dust caked on an old film is not the same as wet oil coming back. If it is wet again, plan to replace the roller soon rather than run it until it locks up.

Roller Won't Turn: What Does a Seized Roller Do to the Track?

A seized roller stops turning, and that is a replace-now fault: the track has to slide across it instead of rolling. To find the culprit, check each roller with the machine parked and made safe. One that will not turn when its neighbours do is the problem.

Replace a seized roller as soon as you can, rather than running on and hoping it frees itself. When you order the replacement, match the position: if it sits in an outer-flange position on a Bobcat E85, for example, the match is the ID08242 outer-flange roller. Then look over the track itself while you are there.

Worn Rollers: Replace One or the Whole Set?

Measure first, then replace any roller whose tread diameter has reached the wear limit for your machine. Use callipers across the running surface and compare the reading with the undercarriage figures in the workshop manual. Check every roller on both sides while you are at it.

The rollers share the machine's weight between them. If several are close to the limit, plan to change them in one visit rather than one at a time. If the track itself is near its limit too, plan both jobs together.

Single or Double Flange: How Do I Order the Right Roller?

Order by position, because many track frames carry single- and double-flange rollers in an order set for that machine. The flanges guide the chain so it runs straight, so fit like for like at each position. Note which type sits where before you take anything off.

Some machines use outer-flange rollers instead, such as the ID17152 roller for the Doosan DX85R-3. The quickest match is the part number cast or stamped on the old roller, or the one in your parts book.

What Should I Check Before I Order a Bottom Roller?

• the machine make, model and series (for example -3 or -5) from the serial plate
• the part number on the old roller or in the parts book
• the flange type at that position: single, double, triple, centre or outer
• how many rollers each side carries, and which are worn, leaking or seized
• whether the track and idlers are also near their limit, so you can plan one job

Browse the bottom roller range, or contact the PartsForMachines team by WhatsApp, telephone or email with your machine model and the old part number. A photo of the roller showing its flanges 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

Do bottom rollers need greasing?

Usually not. Bottom rollers are normally lubricated by oil sealed inside, so there is nothing to grease on the roller itself. Packing a leaking roller with grease will not mend the failed seal, so a new roller is the lasting fix.

Should I check the top rollers as well?

Yes. Check the top (carrier) rollers for oil leaks and cracked shells while you inspect the bottom ones. A leak on a top roller can point to a failed seal just as it does underneath.

How long do bottom rollers last?

There is no fixed figure. Wear depends a lot on the ground: an undercarriage generally lasts longer in loamy farm soil than in sand, gravel or rock. Track tension and how the machine is worked matter too, so measure wear rather than counting hours.

Does track tension affect roller wear?

Yes. A track that is too tight or too loose speeds up wear on the rollers, links and sprockets. Check and set the sag as your operator's manual describes.

Should I replace worn rollers when I fit a new track?

Check them first. Measuring the rollers is easiest while the old track is off, so do it then and replace any at or near their wear limit before the new track goes on.

Can I keep running a leaking roller until the next service?

It is a gamble. Once the oil escapes, the bearings lose lubrication, and that can end in a seized roller or a bigger failure. Replace a leaking roller as soon as you reasonably can.

Can I find a roller by the old part number?

Yes. Type the number stamped on the old roller, or the one from the parts book, into our site search. Many rollers are listed by the machine maker's part number, for example Komatsu 201-30-00060.

What does the flange on a roller do?

It guides the track chain so it runs straight instead of wandering from side to side. Flange designs vary, from single and double to outer flange, such as the ID08218 roller for the Bobcat E80, so match the type at each position.