Abstract: A door closer of the kind having a piston slidably mounted in a bore containing hydraulic fluid and dividing that bore into damping and reservoir chambers. Drive means is connected to the piston to respond to sliding movement of the piston and translate that into rotary motion for driving door connected linkage. The piston is spring influenced in a direction towards the damping chamber, and fluid pressurized by the piston tending to move in that direction bleeds from the damping chamber through an escape port which is controlled by a biased and movable closure member. Normally the closure member is biased into a rest position in which it blocks passage of fluid through the escape port, but it responds to fluid pressure in the damping chamber to move into an open position at which fluid can bleed through the escape port.