door slides.

Can anyone provide a vector here? I have a 2001 Sundancer 280 and the cabin door was difficult to slide back and forth. It sqeaked loudly and just wasn't mving freely. I though maybe the top and bottom rail tracks, bushings, and bearings need to be replaced. So I purchased new ones and then...

So I have had a sticking door on my 280. I cleaned all the tracks and the door opened and closed smoothly but the screw on the top of the door which goes into the slide block keeps working it way out. The other day in rough waters it worked its way all the way out now the block isn't lined...