How do I put the head back down?

Because the unit is pulsing I took it apart to clean everything. In the process I lifted the head (the unit holding the filter) and now it will not go back to it's property position.

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0