C-90 focusing anomaly

Hi guys....I have the older black C-90. The focusing on it, as you know, is by turning the front housing. The front half fits loosely in it's threads and causes a focus shift problem. When focusing, while scope is level, if you apply reward pressure and focus when you let go it falls forward slightly and now the focus is off. If you allow this falling forward to stay there and apply slight forward pressure and focus it will stay in focus till you tilt the scope way up. At a 45 degree angle or higher it stays to the rear. Is there a fix for this problem or do all of the older C-90's have this? Or is there something missing like a retaining spring to keep the front half with a tight fit? Thanks, Gerry

Ain't no springs nor anything else. Just the threads and a couple of screws to prevent the front barrel from unscrewing. It's possible your grease is drying out. See this page for doin' the regrease, which I just did on my new (Orange Tube) C90:

http://www.celestron.com/c3/support3/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=2126

You'll also find this site helpful:

http://astronomyasylum.com/c90.html