The lock on our caravan door has become really really stiff to lock & unlock. I have tried silicon spray and WD40. Anyone got a clever solution as I think I might have made it worse!?
I have read that graphite spray is the stuff to use on locks, but haven't tried it. Rubbing a (soft HB) pencil on a household door key works, so that might be worth a go too.
Wd 40 will wash any grease thats in the lock out.Its not advisable to stick it in any lock though it may free it.A light grease or Graphite grease is the stuff to use,this can be bought from car accessory shops.
We has the same with a Hartal door lock. Tried all sorts from silicon WD40. To sanding down internal parts. After a lot of messing about replaced it but used the existing barrel. 5 min job
Search this site, there is a known problem with some Hartal door locks. Mine was replaced under warranty. Lubrication does not help as the parts are plastic. I seem to remember someone describing how to strip and modify, to cure the issue.