To access and replace the nuts on the backing plate you will need to cut an access hole from the cuddy side of the front seatback. There is no floatation back here so it is an easy reach to the back of the jib track. Replace the screws with stainless steel bolts nuts and fender washers. Make the access hole the same size as an inspection port and you will have future access as well. I think I have uploaded a picture to my profile, but if not email me at
roger.conrad@mts.net and I will send you a picture of the location of the inspection port and the repair to the jib track backing plate.