T-Series Clutch Master Cylinder Cap

[xsteamer]

Hi all, I had problems with disappearing clutch fluid 2 winters ago so this spring I checked master cylinder and it was full. When I replaced the Master Cylinder cap (handtight) the top centre disc popped up. I removed and inspected the cap and deduced that it is some sort of pressure relief device after noticing the pinhole through the main body of the cap. I tried pushing the disc back on but it never really seated tight and remained loose fitting so I used my old discoloured clutch master cylinder cap. Can anyone enlighten me to the nature of the cap and if the disc is loose fitting would it be a problem?

 

[DrEntropy]

This is the small cap? 1-1/8" disk in the center?

The assembly is a baffled vent of sorts. Keeps dirt/FOD out of the cylinder but allows atmospheric pressure as fluid is displaced from pad/shoe wear and the level changes.

Can't see any real danger from a loose center other than the possibility of "stuff" having an easier path to the reservoir.

 

[xsteamer]

Thanks Doc, I'll put the newer cleaner cap back on