The Bucher PM-3551 2-Way Hydraulic Power Unit is a 12V double-acting HPU with a 2-gallon high-density polyethylene reservoir. It powers cylinders both up and down — so it handles dump beds, lift gates, scissor lifts, and any application where gravity won’t bring the load back. 3,250 PSI relief, 1.5 GPM peak flow.
When do I need a 2-way HPU instead of a power-up / gravity-down unit?
Use a 2-way (also called double-acting) HPU any time the cylinder needs to retract under load — closing a tailgate against wind, lowering a lift gate with no weight on it, or holding a position mid-stroke. A power-up / gravity-down unit is fine when gravity does the work coming down, but it can’t push the cylinder back.
- 12V DC, 2-Way (Power Up / Power Down) — double-acting
- 2-gallon high-density polyethylene reservoir
- 3,250 PSI operational pressure
- 1.5 GPM max oil flow
- 6 SAE hose connections
- Operating temp: -20°F to 130°F
- Recommended fluid: ATF (Automatic Transmission Fluid)
- Bucher PM-3551 — made in USA, 100% tested
For a compact 3-quart variant of this same circuit, see the Bucher 2-Way HPU (PM-3551-0667). For lift-only jobs where gravity does the return stroke, see the Bucher Power-Up / Gravity-Down HPU.
