Ok all you rag top owners some tips on maintening your zippers (even works on your pants)
So far I have repaired zippers on several forum members canopies and as it turns out both were what I suspected Zippers were not stuffed at all but full of crud and no lube on teeth
along with stretched sliders (the little black thingy that lets you open and close zip)
first thing you need to do is wash zipper (teeth and slider) for that the best is either RP7 / WD40 or similar to do this get a rag to put behind the zip the spray should have a plastic tube so that it only goes onto the teeth (will not degrade the fabric though) start at one end and was slowly all along the zip one end to the other then wipe teeth, test sliders (if you have sections of zip that have parted when should be closed do not panic)
Wrok slider slowly backwards so that opened section goes back through slider (very slowly doing this as you do not want to damage the zip teeth)
it will take you a while but perserver remember that 30 minutes to do it is a lot cheaper than zip replacement as the proper plastic for your windows is roughly $200.00 a sheet (some trimmers will charge like a woulded bull and fit plastic that is $1.75 a meter and not use the VYBAC window grade plastic)
after you get the slider and sip open properly then get a pair of Multi Grips and come in from the front of the slider (opened section) and place the jaws of the grips on the back of the slider (one one side) and squeeze carefully (trick is not to jam it but close up back of slider) then do same for other side (ensure that the zip teeth are not caught in back of Jaws when squeezing or you will be up for at least a slider and about $60.00).
Then lube the teeth with pure Bees wax
Zips should have the crap washed out of then every couple of weeks if doing lots of offroad work.
Just remember that they are the weakest part of canopy
Hope this makes sense if not call me 03 97426668
(motor trimmer & Sail maker talking here)