I purchased replecement door windows, (frame and glass) from Ecklers for my 61 Impala convert. The original factory assemblies have the lower tracks on the window frames removable to facilitate installation and removal. The replacement ones have the tracks welded on to the frames... Has anyone run into these? I don't seem to be able to install them with the tracks welded on. Can't slip them onto the rollers of the power lift motors. Thanks Lance captainlance@optonline.net