Soft top problem 2003 clk320 w208
 

I just purchased a 2003 clk320(w208). Soft top is inop. I believe it is because the rear headrests will not retract. I have attempted reset by pressing the headrest button up for 8-15sec and then down. The headrest do attemp to go down but very slowly and they come right back up. I attempted to push them down manually while a helper pressed the button and they did go down more quickly but again did not stay down and when they came back up they made a clack clack sound. Does this sound like a pressure issue from the pump or a problem with the valve that controls the headrests?