Today I went to the yard and sure enough one of the 4 hold down on my step was not set in correctly. Since I have the mast still down I took the plunge, it is now off and in the basement.
What I found.
There are 6 3/8 x 1 flat head stainless bolts holding the step onto the deck. These bolts are threaded directly into the fiberglass of the cabin top. There is NO metal backing plate that I can find.
The bolts came out easier than I had expected. I used the largest screw driver that I had (it saw still way to small to correctly fit the slot) fitted with a wrench for additional leverage. The bolts turned out with a fair amount of effort, but the poorly fitted screw driver never jumped out. One of the bolts turned but didn't back out. the threads in the fiberglass must have been striped. I figure that I will drill this one out and create new threads using the West System since almost all the force is sideways.
The bedding compound that had been used 27 years age to mount the step was not holding a thing. Once the bolts were out I just lifted the plate off. There was a fair amount of corrosion buildup between the plate and the deck that will need to be addressed but nothing major.
The bolt holes that Joe is having trouble with go clear though the lower plate. Although mine seamed shallower, that was due to the bedding compound used to bed the plate coming up though the holes.
Mark #585 Jocelyn