Caterpillar S305

The Caterpillar S305 is a hydraulic mobile scrap and demolition shear, the smallest work tool in Cat's S-series shear line (S305, S308, S320, S325, S340, S365, S390). It carries no engine of its own; it draws power from the host carrier's hydraulic system through a dual circuit, roughly 60.6 L/min at 25,000 kPa for cutting and about 20.1 L/min at 10,000 kPa for rotation. Base weight runs about 550 kg (1,212 lb), the jaw opens to roughly 239 mm (9.4 in), and the shear head rotates a full 360 degrees continuously to reposition cuts without repositioning the carrier. It mounts to a Cat skid steer loader in the 236-299 series class or to a mini excavator in the roughly 4-6 t range, with bracket configurations matched to each carrier type. Production runs roughly 2012 through 2020, identified by serial prefix BRD.

Cat's S-series shears share a common architecture across the range, reversible four-edge knives, a straight lower jaw for spreading cutting force, and a continuous rotator, scaled up from the compact S305 to the much larger S390. The S305 exists to put that rotating-shear capability on carriers too small for a dedicated demolition excavator, which is why it targets interior demolition, conduit and light structural cutting rather than heavy steel processing. Current Cat dealer catalogs list an S308 with essentially the same base weight and jaw opening as the S305, suggesting Cat carried the small-shear slot forward into a next-generation model rather than running two parallel small shears, though no formal replacement notice has been published. In the used and parts market, value tracks host-carrier compatibility and attachment-specific wear rather than engine condition: buyers are checking blade wear, pivot-pin and bushing play, rotation-bearing backlash, and hydraulic seal condition, and the parts trade around the S305 centers on those consumable and wear items rather than any driveline component.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.