Abstract: A system for setting a liner in a well casing which has a liner, a liner hanger, a polished bore receptacle, a packer which can be actuated by applying downward pressure to the polished bore receptacle, a running tool, and a junk bonnet which extends between the polished bore receptacle and the running tool and inhibits the ingress of debris into the polished bore receptacle, the junk bonnet and the running tool provided with apparatus which, when the running tool is raised without removing the junket bonnet from the polished bore receptacle, the apparatus cooperate so that when the running tool is subsequently lowered downward force applied to the running tool will be applied to the polished bore receptacle to set the packer, wherein the apparatus comprises a lip which extends radially outwardly from the running tool, and a hook which is biased radially inwardly from the junk bonnet and including a ring which is disposed to restrict radial inward movement of the hook but which can be displaced by the lip to