My metal framed, vertical sliding windows have small tubes to each side that contain a corkscrew like flat metal piece (evidently for friction against some other device inside). One end is anchored to the window frame while the other is anchored somewhere near the bottom of the sliding window. Whatever makes up the friction/spring mechanism within these tubes is failing in a number of windows. The manufacturer name is not apparent. The windows are 16 years old. The local window shops offer the quick answer of.."Time to replace your windows." which a cannot afford at this time. Is there anyone that can direct me toward repair or replacement of the spring mechanism? I would be happy to provide dimensions and a digital photo of the problem if this would help. Thank you very much.