It's the nature of the air seal that Newell used in your coach. Clamping the seal to the coach body cutout and expanding inward toward the slide body is called 'radial-in' expansion. When working with air seals radial-in is the most difficult for exactly the reason you discovered - kinking or buckling in the corners. The Seal Masters S-1 seal used in your coach is spec-ed to expand about 0.25" to 0.3" (max) in corner of radii of 3" to 3.5" before it buckles. This is called the 'stroke'. If your corner gaps are larger than 0.25" then buckling is all but inevitable. About all you can do is attempt to bring the slide body closer to the corner. If the slide body isn't centered maybe you can reduce corner gaps by adjusting the slide position. Another potential solution is to add shoulder pads to your slide corners. Shoulder pads can be extruded out of EPDM or some other flexible weather resistant rubber and adhered to the slide body. Yet one more option is to design your own seal and have it extruded. This is what we did on the Wanderlodge forum:
http://www.wanderlodgeownersgroup.co...ad.php?t=10696
http://www.wanderlodgeownersgroup.co...ad.php?t=12300
http://www.wanderlodgeownersgroup.co...ad.php?t=12171
David Brady
'02 Blue Bird, Wanderlodge, LXi, Living room slide
NC