If the coupler breaks it usually means the pump motor is out of alignment. The most common cause of this is the rubber resilient mounting rings that mount the motor to the base are deteriorating and allowing the motor to drop. Always inspect the mounting ring when replacing a coupler.
Armstrong Couplers and Motor Mnt

Amstrong Motor Mounting Ring Set 874055-000

Armstrong Flex Coupler 806140-001
Armstrong Flex Coupler 806137-001K
Armstrong Flex Coupler 807436-001K
Armstrong Flex Coupler 816665-000K
Armstrong Motor Mounting Ring Set 810120-050


Armstrong Pump 3JE Flex Coupler Insert 875001-800

Armstrong Pump 4JE Flex Coupler Insert 875000-801

Armstrong Pump 5JE Flex Coupler Insert 875000-802

Armstrong Pump 6JE Flex Coupler Insert 875000-803

Armstrong Pump 7JE Flex Coupler Insert 875000-804

Armstrong Pump Motor Mount and Coupler Kit 810120-004
Armstrong Pump Motor Resilient Mount Rings 810120-000

Armstrong Spring Coupler 806026-001

Armstrong Spring Coupler 806168-001K


Armstrong Spring Coupler 810120-006
Pack of 5 Armstrong Pump Spring Coupler 806026-001
Pack of 5 Armstrong Pump Spring Coupler 806168-001
New Products For April - Armstrong Pump