Abstract: A liner hanger assembly has a slip actuation system which is locked for run-in. A piston assembly bolts onto the mandrel in a sealable manner to actuate a mechanical lock. Upon release of the lock, a plurality of springs actuate a sleeve which is in turn attached to the slips to move them relative to their slip seats. The slip seats are preferably mounted to the mandrel without welding and have longitudinal spaces for mud or cement flow therebetween. Load is distributed from each slip through its slip seat into the mandrel without interaction from an adjacent slip or slip seat. A rupture disk ensures that a predetermined pressure is built up before the piston can actuate to defeat the lock. The lock can come in a variety of configurations. One of which is a sliding sleeve over a dog and another is a yoke over a split ring which, when shifted, allows the split ring to expand, thus unlocking the parts.