My disc drive is being really weird.

So this is kinda hard to explain (if you need images just ask), I basically tried to clean the gears to make the disc spin but I can't get the plastic piece back on the gears correctly, and I also have another Wii with a disc drive that won't take discs (it did once but then it stopped taking discs again), so I just wanna know why that disc drive is doing that as well. I hope you guys can help me. Update: The second wii that wasn't taking discs is now taking discs, but it makes this grinding noise and won't read the disc.