Zinc plating without properly.taking everything apart will not work well, an alternative would be to remove all
accessible rust before applying good zinc or zinc/alu spray.
Gents,
I am a happy man now.
Yes, I did follow the general advice and did not take everything apart (upper and lower halves of the sliding rails) ...
but instead brought them to my zink shop as they are.
He, the shop owner (Micky) said, yes, let's give it a try.
What shall I say ...?
They came out beautiful, look like brand new.
The zink plating even went at least partly into the rails.
Will wash out the remaining internal debris/dirt with 'farmers degreaser' (Diesel) and give it a good lube job.
Although I have to get this special grease (Renolit) first that Dirk (secretly) recommended to me.
I am a happy guy now ...!
Happy Ascension Day
Achim
(zink-plated parts collector)