Pump drive coupling 20/950400 JCB 8060/8080, aftermarket

For the JCB 8052, 8060 and 8080 excavators: pump drive coupling 20/950400, an aftermarket part. The card also lists 4426513, 20T-01-31110.

A rubber flexible coupling sits in the drive between the engine and the hydraulic pump. Metal bushes bonded into the rubber ring are bolted in turn to the flywheel flange and to the pump hub; torque passes through the rubber body, which damps engine vibration and shock. Over time heat, oil and load harden the rubber, crack it or part it from the bushes. The engine then knocks when running, the pump turns unevenly and the coupling finally tears. When inspecting it, look for cracks, tears and swelling in the rubber around the bushes; oil-soaked rubber is also a reason to replace it. Check the hub splines and the pump shaft when the coupling is changed. Check the bolt threads in the flywheel flange during the change.

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.