Cobra top hinge plate bolt failure

Last year "YO" told us about how he nearly lost his trailer top after
both bolts securing one trailer top hinge plate failed. Of course I
checked my bolts and all four were secure at that time.

Yesterday I arrived at the club field and had a problem releasing the
left rear top latch. Sure enough the outer bolt on the left hinge
plate had failed and this allowed the top to move back slightly and
bind up the rear latch. I was able to find replacement bolts at a
local hardware store. 5/16 x 3.5 inch are very close to the
diameter the original metric bolt and provide more load bearing
unthreaded shank.

The bolts in question go through the front handles, the trailer glass
top, the trailer top frame (with an internal spacer block), a spacer
plate, and then the main hinge plate. All the parts try to misalign
under load. With the help of 5 people I was able to align all the
pieces well enough to get the new bolt in and was then able to rig and
fly the task.

Another isolated failure? No. While I was working on it GW walks up
and says he found the same bolt failed on his trailer the previous
evening. My trailer is 9 years old and GW's I think 10 years old.
Both are glass top but I don't know if that is significant. So 3
known failures of these bolts.

Do you feel lucky?

Andy (GY)