I found this question is from diy.stackexchange.com:
"Many houses in my neighborhood are about 5 years old and are experiencing similar problems with their gutters. The nails holding them up are pulling out little by little. A couple homeowners had theirs fall off. I took a look at mine and saw a few nails sticking out. What's the correct way to fix this?Just hammer them back in and hope for the best?"
Here is a solution from a reader:
"Fill holes with adhesive (Liquid Nails) and hammer back in.
You could also hammer in a different kind of nail. If the nails are loose and pull out easily, just pounding them back in won't help much."
Here is another interesting and novel solution:
Take some toothpicks and dip them in wood glue (e.g. tightbond).
Stuff as many toothpicks into the hole as you can, snapping them off flush with the hole.
Put the nail/screw back in (while the glue is still wet).I find myself doing this most for loose door hinges, but it works for pretty much anything. Once the glue dries, the result is better than new.
Maybe the above suggestions would help but there actually is a very good product that solves the gutter spike problem. The product is called Fasten Master. You can buy it at The home depot and even Walmart.
All you do is remove the loose spikes and drill this long screw through the gutter and into the fascia board. This screw is so strong that you don't need to replace every loose spike. If you have a whole gutter pulling away from the fascia, no need to replace every spike. You could just replace every other spike with a Fasten Master, and just pound the remaining spikes back in again.