So I picked up some Sikaflex from the local RV shop. They had both Proflex (Geocel), Sikaflex and numerous other Silicone based sealers. After speaking to one of the service folks they recommended either the Profelx or the Sikaflex but said they use the Sikaflex when they make their repairs... SO there you have it.
Since I had already done this once before I DO NOT want to have to do this a third time! The new old Boss 310 stuff had pealed right out in a nice long piece. It was very flexible and formed a beautiful "gasket" along the ridges of the seals and into the channel where the seal sat but obviously that was not enough..
I decided I would really get the area clean this time. I removed the outer rubber "D" seal off the "T" shaped flanges it was keyed into. I was surprised to find the T flange was actually only rubber as well and was actually part of the molded upper wiper seal. The wiper seal had some kind of adhesive (gray colored) gluing it onto the sidewall of the trailer and had also been held in place by staples. My guess is they were there to hold the seal in place while the glue dried?? But in typical fashion.. None of the staples were actually seated fully, most stuck out 1/8" or so... Thank FR! LOL.
So what did all this mean? Well the D seal being sealed is not realy that important. I looked at the other D seals around the slide and they were not even sealed at all. The part that was important, and actually where the leak was, was the upper wiper seal. So I scraped out what I could from behind the wiper seal without actually pealing it away from the wall. I want to avoid this if possible..
I then sealed the wiper seam and let that set a bit. Once it was ready for the final coat, I put the "D" seal back on and sealed that onto the wiper seal. I sure hope this solved the leak! If not I might need to surrender!!!!