Idler pulley 320/08685 JCB JS, genuine

For the JCB JS excavators with the Dieselmax engine: idler pulley 320/08685, a genuine JCB part. The card also lists 320/08924.

The stud length and face type (flat or grooved) are set by the belt layout; the wrong pulley pulls the belt out of line. The bearing is sealed and needs no greasing; the whole pulley is replaced. One bearing failure can stop the whole belt drive: with a broken belt the alternator stops charging, the water pump stops turning and the engine overheats quickly. So the pulley bearing is checked for noise and play at every belt change. If the pulley has play or feels rough when turned, replace it. The belt and pulleys are usually renewed together. The pulley may have a steel or plastic body, with the bearing pressed in.

Specifications

Compatibility

The part is listed for JCB JS excavators with the Dieselmax engine. The catalogue also has the aftermarket version of this part. Other parts are in JCB Dieselmax engine.

Fitting

Release the belt tension, remove the old pulley and tighten the new one to the specified torque. Route the belt correctly and release the tensioner. Thread locker can be applied to the pulley bolt.