I've had my Inspiron 8000 since May 2001. I've had the hinges repaired in July 2002, and I'm about to call and have them repaired again. This is the only symptom I had: increasing play in the LCD when opened (between 5 to 10 degrees).
I believe Inspiron 8000, 8100, and 8200 all use the same basic case, so this is what is required to repair your system. The whole plastic panel which holds the LCD must be replaced. The hinges themselves do not come detached from the LCD panel.
It's not a functional problem, but it makes the laptop feel cheap to me...so I get it repaired. It's no problem for me since they repair it for free, but I'd rather they give me high-quality hinges. I still love Dell and would buy another, but this goes to show that nothing is perfect!
Let me know if you have any questions about my experience. I'll be glad to help!
As near as I can tell the replies to the original question are addressing two different problems with the hinges. Besides the cracking there seems to be a problem with the screws coming loose and also a problem with the actual ease of movement of the hinges themselves.
If the screws stripped out I would try tapping new 3mm threads into the existing 2.5mm stripped ones. If that did not work then I would try small sheet metal screws to secure the hinge assemblies to the base. I wouldn't buy a new top until none of these remedies worked any more.
Regarding movement of the hinges. Don't ever oil them. I tried this once and shot some WD40 into the hinges. It had the effect of making the hinges so loose you could no longer keep the screen at any desired angle. These hinges depend on the friction of the cast metal and are not designed to have any lubrication in there. If the hinges wear out then I can't think of any remedy other than replacing the top. If they crack before wearing out and you can get it replaced under warranty then so much the better.
The hinges are attached to a large metal piece that forms the strength of the top. The metal piece is held to the plastic top with two screws. One could buy a new top, remove the metal plate with the hinges, and then sell off the nice new plastic top on ebay to somebody who had theirs all scratched up. Probably would fetch ten bucks or so.
Finally, I have discovered that when ordering parts, in most cases, it is cheaper to order parts for the newer models if they will work on your machine. Last time I checked the top assembly for an I8200 was cheaper than that for and I8000 or I8100 yet they are physically the same but with different part numbers.
Don't really know anything about cracked hinges. It is my observation that the hinges become looser and looser over time from normal use and eventually the lid will not stay in just any position you want it to. When it gets to that point I would replace mine. As far as a "major" problem is concerned about the worst thing that can happen is the hinges break and the lid might not stay up at all. At this point one could still use an exterior monitor until replacement hinges are obtained if not on hand.