Ordered this Stopsy http://wohnmobil-caravan-zubehoer-s...y-Tuerstopper-Kastenwagen-Schiebetuer::1.html to add an extra additional stainless steel stop point for the sliding door on our van conversion - much as we love the door wide open on sunny days there are times when we just want it...
SandSwww.magnummotorhomes.co.uk sell a simple fitting for allowing the sliding side door to stop where you sometimes want it to stay open. It is called a - Door Stopperz - and can be found in their Fiat Ducato Special Parts section.
I needed one as when fully open the rear side window cannot be opened (well done Swift R&D department). All that was needed was something thin on the top track. Because the top track takes the majority of the door weight, it only takes a small object to stop it in it's tracks 'sorry about that'.
So I experimented with various thicknesses and believe or not ended up with two pieces of broken hacksaw blade, strategically stuck on the surface where the roller runs. They are about 40mm apart so the roller is stopped both ways, but is easily overcome to open or shut the door. Patent pending
I use an adjustable wooden or plastic curtain rail. Usually available at the shows or I’m sure, most DIY stores . Can be put either side of the door depending on which way the site slopes, as it is adjustable, any width you want. £2-3 ish.
There have some bad reviews of 3D printed door stops that have disintegrated after little use so would be wary of what material is being glued (possibly permanently) to the bodywork. We went for the stainless steel Stopsy because of this although the plastic & aluminium options are much cheaper.