A belt conveyor is simple in principle and unforgiving in practice. A long conveyor has a drive, several pulleys, a take-up and hundreds of idlers, all working in dust, rain and sun, often far from the workshop. When a drive pulley bearing fails or a gearbox runs dry, everything upstream stops. Good conveyor lubrication is mostly about doing a few things correctly every time, and knowing what not to touch.
Grease drive, tail, bend and take-up pulley bearings with a good EP grease (lithium complex, or calcium sulfonate complex in wet and hot conditions), sized with G = 0.005 × D × B grams per shot. Leave sealed-for-life idlers alone and replace seized ones quickly. Use the EP gear oil grade the gearbox maker specifies, fill fluid couplings with exactly the oil and quantity the coupling maker states, and use only the lubricant the backstop maker allows.
| Component | Lubricant | Typical interval (follow the maker) |
|---|---|---|
| Drive and head pulley bearings | Lithium complex NLGI 2, or Ca-sulfonate complex in wet, hot or very dusty duty | Every 1–3 months, by quantity |
| Tail, bend, snub and take-up pulley bearings | As above | Every 1–3 months |
| Carrying and return idlers | Usually sealed for life: no grease | Inspect; replace seized idlers |
| Drive gearbox | EP gear oil of the maker's grade, often ISO VG 220 or 320; PAO synthetic for hot or continuous duty | Check level weekly; change as specified or on oil analysis |
| Fluid coupling | The oil the coupling maker specifies, often a light mineral oil such as ISO VG 32 | Check for leaks; fill quantity exactly as stated |
| Backstop (holdback) | Only the lubricant the backstop maker specifies | As specified |
| Take-up winch, wire ropes, chains | Chain and wire rope lubricant | Monthly, or as conditions demand |
Pulley bearings are usually spherical roller bearings in plummer block housings. They turn slowly to moderately, carry high loads and sit in dust.
Most modern idlers are sealed for life and are not meant to be greased. Adding grease can damage the seals. What matters is spotting failing idlers early: listen for noise, look for idlers that do not turn, and use a thermal camera on long conveyors. A seized idler wears the belt and, with a dry belt rubbing on a hot shell, can be a fire risk. Replace it promptly.
A fluid coupling transmits torque through oil, so the type and the fill quantity both matter. Too little oil makes it slip and overheat; too much raises the starting torque and pressure. Fill exactly as the coupling maker states, with the oil it specifies. Never replace a fusible plug with a solid plug or with one of a higher temperature rating than specified; it is the coupling's safety valve.
Backstops stop an inclined conveyor running backwards. Use only the lubricant the backstop maker specifies. Some sprag-type backstops must not receive oils or greases containing solid additives such as MoS₂, because they can change how the sprags grip.
Walk each conveyor with a grease gun, a thermometer and a notebook: grease pulley bearings by quantity, check bearing temperatures, listen for noisy idlers, check gearbox levels and breathers, look for coupling leaks, and note belt tracking problems. Write down what you find.
Gravity and winch take-ups use wire ropes and sheaves; chain conveyors and bucket elevators use chains. Both need a penetrating lubricant that reaches the inside of the rope or chain. Our wire rope lubrication guide explains how.
Crushers and screens feeding the conveyor have their own needs; see our stone crusher lubrication guide. For the full range, see our page on mining and quarrying lubricants.
How much grease should a conveyor pulley bearing get?Use G = 0.005 × D × B, where G is grams of grease, D is the bearing outside diameter and B is its width, both in millimetres. Follow the bearing or housing maker where they give a figure.
Should conveyor idlers be greased?Most modern idlers are sealed for life and should not be greased. Inspect them and replace seized or noisy idlers promptly.
Which oil goes in a conveyor fluid coupling?The oil the coupling maker specifies, often a light mineral oil such as ISO VG 32, filled to the exact quantity stated.
Which gear oil is used in conveyor drive gearboxes?The EP gear oil grade the gearbox maker specifies, often ISO VG 220 or 320, or a synthetic PAO oil for hot or continuous duty.
Running conveyors in a mine, quarry, cement or power plant? Send us the conveyor list with gearbox and bearing details, and our team will prepare a lubrication schedule and quote.