Greetings !
12A 85 FB -about to refurb clutch secondary cylinder -have Mazda parts -the rubber type seal seems insubstantial- but no doubt works- but I'd like to reduce chances of air getting into cylinder .
Question ? If I were to put a rubber washer say 5 mm thick with hole to take pushrod smoothly then RTV on outer side -all covered by corrugated rubber sleeve -supplied with kit - Would I be wasting my time ?????? or is it good idea?

 

Under the assumption that the clutch slave cylinders are the same across the pond....

I just rebuilt mine using just the parts included in the rebuild kit (piston+seal, spring and outer boot) and have no issues with leaks...
You shouldn't be concerned with air in the system as there is a bleeder on the slave and you'll be flushing the whole system out anyway..

Cheers,
Kam

 

Thanks for comeback - just done mine today and guess I was just looking to improve whilst it was out - however I did notice that replacement kit rubber seal is much better than original,anyways alls in and I got a stiff one -but will bleed again later as I'll let the hydraulics settle and bubbles in fluid to big up .