Bingo - this is exactly how to resolve the problem. It's also a good idea to beef out the contact area about 1/8" or less with some duct tape and clear plastic wrap so that there is a little bit of clearance between the chain plate and deck - this can then be filled with 4200 as Phil suggests.

:: before I injected my epoxy and micro balloon mix , I
:: reinstalled my chainplates with a wax coating and let
:: everything form perfectly around them , eliminating the
:: need to recut and making a perfect slot.. Then remove ,
:: clean, and reseal. did this in '07 . no leaks since.

:: used 4200 sealant