The best procedure I found for the "u" seal is to use a dab of sealant at the ends where it butts against the cover, but use no sealant anywhere else on it. instead just "spit" on it, then place it in the groove, and slide the upper cover on. The spit is the slickest thing known to man, and allows the seal to retain perfect form and position as the upper cover easily slides over it. When the spit dries it causes good adherance of the seal to the cover with no globs of sealant, no drying of sealant later, etc. Works great! You've all probably used spit on 0-rings - same deal.