sliding door sticking

The sliding door of our van has started sticking. The left side opens a tiny bit and, if you can get your fingernails in, you can just about open it.

Any suggestions for what we should lubricate/replace/adjust?

Thanks

LR
PS If this turns up twice, sorry. I typed it in before but no idea where it went

If its only just started doing it use some silicone spray as it does not stain or discolor. Just watch out if you plan to get any paintwork done soon, as it makes it a little harder for a bodywork shop to get the paint to stick. Use something to catch the spray before it ends up on bodywork. There are guide blocks in the runners, lock mechanism etc. Should be a non intrusive way to see if lubrication helps. If it moves give it a little spray.

Have you seen this thread
https://brazilianvwbay.forumotion.com/t7686-help-sliding-door?highlight=sliding+door

Just a thought if it has not quite failed yet or leads you down the right path.

When open does the door move as expected, or is it not tracking right? If not maybe its a similar issue to the following
https://www.thesamba.com/vw/forum/viewtopic.php?t=642199

Good idea. I've got some silicone spray, but the nozzle is broken so it sprays everywhere ;-)

Once open the door is fine. Its just that first half-inch of movement that I need.

Ta