I washed and re-sprayed my cockpit cover for the AT this past summer. Took the cover to a coin laundry and used the biggest washer and dryer they had to clean it first. Didnt use any heat in the dryer.
Then I bought a 3M Teflon Waterproofing from Boaters world. Poured that into a pressure sprayer and sprayed the canvas while it was spread out on the lawn.
Worked very well, water beads and rolls off like a fresh waxed car.