reinforcing/repairing garage door bottom rail to stiles
I have a 20+ year old wooden garage door and the bottom metal horizontal rail (the one that has the rubber weatherstripping underneath) needs to be better attached to the interior vertical wooden stiles. Over the years I have used #8 x 2" hex head sheet metal screws driven up from underneath the metal horizonatal rail into the veritcal stiles but find that over time they back out. So, this time I was thinking of doing something different but wanted to run it by the experts here. I was thinking of three options:
1: just add a few additional vertical stiles to the bottom garage door panel and fasten four angle brackets to each. I would screw in the angle brackets to the additonal wood stiles, and then use machine screws with nylon locking washers to fasten the other legs of the brackets to the rail below and the "frame" of the panel segment above. This way, there are no screws fastening the bottom rail to the additional reinforcing stiles. Because there is a strut running across the interior side of the door, it would be hard to install the brackets on the existing stiles so perhaps I could just use my sheet metal screw approach in new holes on the existing stiles and with the rail now more firmly held to the reinforcing stiles, maybe they won't back out so easily.
2. use threaded inserts into the existing stiles but I have no experience using this type of fastener. I heard they are somewhat tricky to install (especially when working on a door half way open). Obviously, I would then use machine screws penetrating the rail from below and maybe use some Loctite.
3. same as (2) but try some hanger fasteners (the ones that have the sheet metal style screw on one end and machine threads on the other) and use nylon locking nuts from below the rail again.
Not sure which is the best approach but I'm thinking (1) is probably the best. My only slight concern is the extra siles might add a bit of weight to the door and understand the doors as somewhat matched to the torsion springs but think that two or four cedar stiles would probably not add too much additional weight and throw things off.
Thanks in advance for any input.