"Good idea to wash regularly and wipe down afterwards any metal parts of MR or TR with a little light oil (eg wd40) which then adheres and protects metal from corrosion."
NOT GOOD IDEA ANYWHERE NEAR BONDING OR JOINT. RHC DO NOT RECOMMEND WD 40.
(There have been previous discussions on this matter - if you are any doubt, ask RHC first or at least ask a UK R44 engineer who will give you the RHC gospel on WD40.)