CONVEYOR BELT TROUBLESHOOTING – PROBLEMS & FIXES

Find the Cause,
Not Just the Symptom.

When a belt gives trouble the first reaction is often to blame the belt and order a new one. In our experience, more than half the calls we get are solved on the conveyor, not by changing the belt. Below are the problems we are asked about most, written as what you see → what usually causes it → what to do.

1. Belt runs to one side at the same spot all the time

Usual cause: An idler set or pulley near that spot is not square, the structure is bent, or material has built up on a return roller.

What to do: Check the idlers just before the point where the belt starts to move off. Clean any build-up. Square the idler frames. If it is at the tail, check tail pulley alignment and carry-back on the pulley face.

2. Belt runs off at one point that keeps moving along the conveyor

Usual cause: The belt itself is not straight – usually a joint that was not made square, or a belt that has been stored badly and taken a set.

What to do: Watch the joint as it goes round. If the belt moves off every time the joint passes, the joint has to be remade square. Mark the centre line before cutting.

3. Belt runs straight when empty but moves off when loaded

Usual cause: Material is landing off-centre at the loading point.

What to do: Fix the chute so material falls in the centre of the belt, in the direction of travel. Add a deflector plate if needed. Do not correct this with idlers.

4. Belt slips on the drive pulley, smell of burning rubber

Usual cause: Too little tension, worn or missing pulley lagging, water or oily material between belt and pulley, or overload.

What to do: Check the take-up is free and the counterweight is correct. Re-lag the drive pulley – diamond lagging drains water better (see pulley lagging). Do not over-tighten a screw take-up to hide the problem.

5. Top cover wearing fast at one point along the belt width

Usual cause: Skirt rubber pressing too hard, exposed steel on the skirt board, or sharp material hitting the same spot at the loading chute.

What to do: Adjust the skirt so it only lightly touches. Replace worn skirt rubber. Add impact idlers or an impact bed at the loading point.

6. Long cut or groove along the top cover

Usual cause: Something trapped between the belt and the chute or skirt – a stone, a piece of steel, or the chute liner itself.

What to do: Stop the belt and remove the object. Check chute clearance. Fit a tramp metal detector or magnetic separator belt if steel pieces are common.

7. Edges worn, frayed or folded

Usual cause: The belt has been running against the structure for a long time because of tracking problems.

What to do: First fix tracking. Minor edge damage can be trimmed and sealed. If fabric is exposed along the edge, water will enter and the plies will separate – repair early.

8. Cover cracking in small lines across the belt

Usual cause: Heat ageing (material hotter than the belt grade), ozone and sunlight on a belt stored or running outdoors, or very small pulleys.

What to do: Check the actual material temperature at the belt. For hot material change to the right heat resistant belt or ultra heat resistant (UHR) belt. Check pulley diameter against the belt thickness.

9. Cover swelling, soft and sticky

Usual cause: Oil in the material – the cover grade is not oil resistant.

What to do: Change to an oil resistant belt. If the material is also hot, use an oil & heat resistant (ORHR) belt.

10. Joint failing again and again at the same place

Usual cause: Joint length too short for the belt rating, wrong adhesive, joint made in wet or dusty conditions, or joint not cured long enough.

What to do: Follow the full joint procedure in our belt jointing process. Check that the joint passes over pulleys that are large enough.

11. Plies separating (belt opening up in layers)

Usual cause: Water entering through cuts or edges, or pulleys too small for the number of plies, which bends the belt too sharply.

What to do: Repair cuts early so water cannot enter. Check the pulley diameter. If the separation is long, that section should be cut out and a new piece joined in.

12. Material rolling back on an incline

Usual cause: The incline is too steep for a plain belt, or the material is wet and slippery.

What to do: Use a chevron belt for moderate inclines, a sidewall belt for steep ones, or a rough top belt for bags and boxes.

13. Belt stretching and take-up running out of travel

Usual cause: Normal initial stretch in the first weeks, or a belt with too low a rating for the load.

What to do: Some stretch at the start is normal. If the take-up keeps moving after the first month, check the belt rating with our belt rating chart and share the conveyor data with us.

14. Carry-back falling all along the return side

Usual cause: Scrapers worn or not tensioned, or sticky material.

What to do: Service or replace the primary and secondary scrapers. Clean the return rollers. For very sticky material ask us about a smoother cover finish.

A Quick Rule of Thumb

Still stuck? Send us photos of the damage, the belt marking and a short note of what you are conveying. Our team will tell you honestly whether it is a belt problem or a conveyor problem.

Need a Belt Quickly?

Many common sizes are available from ready stock. Share your old belt details or a photo of the belt marking and we will match it. Reach us on +91 98275 92612 / +91 90395 92612 or info@shrirambeltings.com, or use the enquiry form on our contact page.