Have you taken the box off to see what went wrong as in is the seal still in place ?? as has been said ideally no lube should be used on the outside & also I keep an eye on how easy the seal goes in & if it goes in very easy I put a smear of silicone on the very outside face outer edge to housing rim, just a bit of piece of mind ... As has been said you must put a smear of grease on the complete seal lip & even a light bit on the crank too ..