Pump drive coupling 331/20717 JCB 8030/JS30, aftermarket

For the JCB 8025, 8026, 8027, 8030, 8032, 8035 and JS30 mini excavators: pump drive coupling 331/20717, an aftermarket part.

An elastic flange coupling consists of a flexible flange bolted to the flywheel and internal teeth that engage a hub on the pump shaft. The flexible flange material damps the engine's torsional vibration, softens shocks and takes up small misalignment between flywheel and pump. The photo shows a 50 Shore A hardness marking on the flange. Couplings of this type are widely used between the engine and hydraulic pump on mini and midi excavators. Over time heat and oil harden or crack the flexible material, and play grows as the internal teeth wear. Knocking from the pump side when the engine runs and stops shows that the coupling is worn; if it breaks, the machine loses all its hydraulics.

Specifications

Compatibility

Other parts are in Hydraulic pumps.

Fitting

To change the coupling, separate the pump or engine side and clean the flywheel flange and pump shaft. Tighten the new coupling bolts to the specified torque in a cross pattern and grease the splines as the manufacturer recommends. After assembly, run the engine at idle and listen for knocking and vibration.