Lot of times the alignment pins and holes are dirty or the hinges have a lot of slop. Also as JSC has stated - could be warped (worse case). You might be able to surface the faces to get a better seal. Close the mold and hold it up to a light source and look through the seal - gives you an idea of how bad the misalignment is and where you have to surface the face.
No.08 is a very old number - don't have that listing.