Aro 637119-62-C Diaphragm Pump Repair Kit Buna-N Fluid End

Kit Contents and Compatibility

The Aro 637119-62-C fluid end repair kit restores air-operated double diaphragm pumps using Buna-N diaphragms and acetal check balls. It includes two diaphragms, four check balls, fourteen O-rings and fourteen seals. The kit fits ARO pump models 666100-162-C, 666100-362-C, 666100-462-C, 66610A-362-C and 666120-362-C, and cross-references Grainger part 2P598.

Sustained Operation Reliability

Under continuous cycling at up to 120 psi media intake pressure, the Buna-N diaphragms resist swelling and cracking from common industrial fluids. The acetal check balls maintain consistent sealing over long runs, reducing leak paths that develop when softer materials deform. Fourteen O-rings and fourteen seals refresh every static joint in the fluid end, preventing the gradual pressure loss that degrades flow rates during extended shifts.

Upgrade From Worn Fluid Ends

This kit replaces a complete fluid end assembly when diaphragms have lost elasticity, check balls show pitting or O-rings have taken a permanent set. It is not for pumps requiring PTFE or Santoprene diaphragms, nor for units operating above the 120 psi rating. The repair is worthwhile when the air motor and centre section remain sound but fluid-end leakage or erratic cycling signals seal fatigue.