A fluid displacement and pressurizing device having a housing and a carrier member. A plunger extends through the carrier member and plunger engaging structure is retained by the carrier member. The plunger engaging structure is selectively engageable with and disengageable from the plunger. The housing and earner member are configured such that the carrier member is transversely installable in the housing. Preferably both the carrier member and the plunger engaging structure form a sub assembly and the sub assembly is transversely installable in the housing after having been assembled. By providing that the carrier member is transversely installable as a sub assembly which includes the plunger engaging structure the device is easy to assemble and lends itself well to an automated assembly process. Integral handle and gripping features make control and operation of the devices easier and allows for torsional operating loads to be resolved without reaching the device body.
