I have a Rapidex - a post 1960 model as it doesn't have a date stamp mentioned by Laguna.
Some months ago I needed to have a repair carried out so I contacted ' the main man ' Garry Mils of the Mill Tackle Co. This he did, along with a general service as the reel had not seen light of day for 50 years.
Please read ' Centre pin reel repairs ' under ' Search ' and in particular the fact that he recently moved premises, although this probably completed by now.........
What he did tell me is that this particular reel was made in the day when lines were much thicker and consequently did not suffer the problem of line managing to find its way into the drum area if using ( say ) the 3lb bs lines of today.
However, as my reel is in almost new condition without any wear or slack from long use I do use light line with it and it works very well with my Drennan Ultra rods..
I do have another, almost identical reel, the Flick-Em Perfection by Allcocks, which has been in use for all its life and this DOES suffer with the line problem, although it is used with care on a weekly basis.
Garry Mills is very helpful and a phone call for a chat well worthwhile - in fact a necessity, I would suggest !!
ps Depending on the age of your reel the internal's may well be different to mine so establishing its age a good starting point.................