|Posted: August 26 2010 at 09:49 | IP Logged
I have the identical cabin door on my '87 Portofino. Apparently, mine was replaced a few years before I bought it. Mine was having a binding/chattering issue as well. I cured it by spraying silicone on the tracks as well. I sometimes wipe the excess off, but generally I just spray the tracks. I only have to do this about 3x/yr. It slides very nicely.
Maybe you could try just spraying it and not wiping it. You may need more lube on the tracks.
That's Austin, Texas Y'all!