E61 Water Inlet Valve Spring This spring provides the return tension for the upper mushroom/water inlet valve in an E61 group head, and it's the same spring used in Pavoni manual-fill water inlet valves (listed there as VBM_61). A weak or fatigued spring is a common, overlooked cause of a group head that won't fully shut off between shots. SPECIFICATIONS 13 x 42 mm COMPATIBILITY Fits: E61 group head water inlet/upper mushroom valve; Pavoni manual-fill water inlet valve (as VBM_61) INSTALLATION Requires opening the group head to access the upper mushroom assembly, a job for someone comfortable with basic E61 teardown. PRO TIPS If the group is weeping continuously even with a good o-ring and gasket, don't overlook the spring, a collapsed or weak spring lets the valve seat imperfectly under water pressure even when every seal is brand new.