Inline pumps with rear attachable syringes include a pump and a syringe with each designed so that the pump syringe system may be easily coupled and decoupled in the field. An end mount block on the pump has a slot shaped to accept a similarly shaped plunger button and plunger rod on the syringe. A user aligns the plunger button of the syringe next to the slot on the mount block of the pump, and slides the plunger button and rod into the inner cavity of the pump. Both the pump and the syringe have threaded couplers which securely couple the pump to the syringe by rotating the couplers with respect to each other.
