Weatherstripping troubles

Do you have a tool, similar to a dull pizza cutter, that can be used to press or squeeze replacement new pile into place without partial disassembly of the window frame? I have an unidentified bottom track sliding glass window. This window is held together with a continuous gray rubber gasket within an aluminum frame. Surrounding the frame is an aluminum track holding gray wool pile. This pile is worn and must be replaced. The wool pile is your 58-045 (9/32 X 1/4"). The wool pile along the top and bottom of the alum. window frame is easy to remove and easy to slip-in (install) the new replacement pile. Unfortunately this does not apply to the longer sides of the alum. glass frame. On the bottom and top of the frame is a moulded white plastic piece attached by a screw. This screw (one in each corner) holds the four frame pieces together. One would think to merely remove the screws and plastic pieces, then pull the corner of an aluminum side out a little would be enough to reveal the track, .... pull out the old pile and replace by sliding in new. However, the alum. pieces fit tight together and are slightly bowed in the center. I am afraid to pull any of the four alum pieces of the frame apart fearing this may tear the rubber seal or worse. This is the reason for asking if Swisco sells a tool as described above. Any other suggestions?

Harold