tystik

Bare with me as i am new to the forum. i have a friend who has a 2003 specialized that came with a rst capa tl shock. i know this is more of an entry level shock, but its all he has right now. the shock rebounds extremely hard{bottoms out on the rebound} no matter what adjustments are made. i can feel a solid thud when the wheel comes off the ground and it feels like something maybe loose or worn. i can not find a manual or site that tells me how to rebuild this shock. does anyone know of one or have any suggestions to fixing the problem til he can move up to a more comparable shock by todays standards? thanks