Rattling tapping and grinding noise on spin

What Does a Worn Drum Pulley Sound Like?

The noise pattern is distinctive and consistent. During a wash cycle at slow drum speeds, it presents as an intermittent metallic tapping or clinking. As the machine speeds up into a spin cycle, the same fault produces a grinding, knocking, or rattling sound that worsens as spin speed increases.

The noise changes character with drum speed because the amount of movement in the worn pulley increases with the centrifugal forces and vibration of a faster spin. At slow speeds it taps; at high speed it grinds.

Do not confuse this with drum bearing noise.

Drum bearings also produce a rumbling or grinding sound on spin, but bearing noise tends to be consistent and continuous throughout the spin, getting louder as speed increases. A worn pulley tends to produce a more irregular knocking or rattling pattern. See our guide: what do noisy drum bearings sound like?

What Is the Drum Pulley and How Does It Work?

The drum pulley is a large wheel mounted at the back of the drum, behind the rear panel of the machine. The drive belt runs around this pulley and around a much smaller pulley on the motor. When the motor runs, it drives the belt, which turns the drum pulley, which rotates the drum.

On most modern machines, the drum pulley is made of plastic with a metal insert pressed into the centre. The metal insert is what engages with the drum shaft – it transfers the rotational force from the pulley to the drum. When this metal insert wears, it loses its tight fit on the shaft and allows the pulley to move laterally – left and right – even while the central bolt holds it in place.

This lateral movement is what generates the noise. The bolt holds the pulley on, but the worn insert means the pulley rocks slightly with every rotation.

How to Confirm the Drum Pulley Is the Problem

The confirmation test is straightforward – and if the pulley is worn, the movement will be obvious.

Unplug the machine from the mains before accessing the back panel or touching any internal components.

1. Unplug the machine and pull it out from the wall to access the back panel.
2. Remove the rear panel – usually held by screws around the perimeter. The drum pulley is clearly visible as a large wheel at the centre.
3. With the belt still in place, try to move the drum pulley left and right (laterally, parallel to the drum shaft). On a good pulley there should be no movement at all. If the pulley rocks or shifts side to side – even slightly – the metal insert is worn.
4. If there is obvious lateral play in the pulley despite the central bolt being tight, you have confirmed the fault. The pulley needs replacing.

How to Replace the Drum Pulley

Replacement is manageable as a DIY repair, but the pulley bolt requires careful attention. Getting it wrong can result in a sheared bolt – an outcome that can write off the machine.

If the pulley bolt shears, it may be impossible to remove without professional equipment.

Drilling out a sheared bolt and restoring the thread with a tap and die set requires specialist tools and experience. In most cases a sheared pulley bolt means scrapping the machine. Treat this bolt with care.

Before you start: check the bolt thread direction

Most drum pulley bolts have a standard (right-hand) thread and undo by turning anticlockwise. However, some machines use a left-hand thread that tightens anticlockwise and undoes clockwise – the reverse of what you would expect. If the bolt resists and shows no sign of movement, consider whether you may have the thread direction wrong before applying more force.

Dealing with the locking mechanism

The pulley bolt must be prevented from working loose during use. Manufacturers use several methods:

• Loctite (most common on modern machines): a thread-locking adhesive applied to the bolt. The bolt will feel very stiff to begin with, but once it starts to break free it will turn normally. Do not mistake this initial resistance for a stripped thread or wrong direction
• Tab washer: a metal tab that is bent against a flat on the bolt head to prevent rotation. The tab must be bent back before the bolt will turn
• Locking spacer: a plastic or metal spacer fitted under the bolt that adds friction resistance. Remove it carefully and retain it for refitting

Removing and fitting the bolt – critical tips

• Use the correct size spanner for hexagon head bolts. A spanner that is slightly too large will round the bolt head. Do not use mole grips, pipe pliers, or adjustable spanners unless as an absolute last resort – these all risk rounding the head.
• Use a long spanner for leverage. The initial break torque on a Loctited bolt can be significant. A longer spanner allows controlled force rather than sudden jerks that risk damaging the bolt.
• If the bolt has a Torx (star-shaped) head, use a Torx socket, not a Torx bit. A bit alone cannot provide enough leverage and the head is easily damaged. Torx pulley bolts are particularly vulnerable to stripping even with the correct tool – work carefully and deliberately.
• When refitting, apply new Loctite if the original bolt used Loctite. Without thread locking compound, the bolt will work loose during use and the pulley will fail again quickly. Use medium-strength (blue) Loctite. Do not use red (permanent grade) as it will make future removal extremely difficult.
• Do not overtighten. The bolt must be firm, but excessive torque increases the risk of shearing. Tighten firmly and evenly, particularly if using Loctite which provides additional retention.
• If a tab washer was fitted, bend the tab back into position against the bolt head after tightening to restore the locking action.

Frequently Asked Questions