It could be metal, wood or both. Roll the chair over. Torx down all the screws that hold the two main rocker springs. Most rocker recliners have whats called rocker blocks.They are located on the left and right side of the frame. The main rocker springs are connected them. Check the joints on the rocker base to see if they are loose. They can be glue and clamped if they are not to bad. Get some mineral oil and a dropper and put two or three drops around the mechanism. Put a towel or something under the chair so that the oil dose not get on your carpet. Good-luck.
Irvin
April 2009