[ROVERNET - UK] P6B Master cylinder question

[Ali Al-Abbasi]

All

I'm about to pull the master cylinder out on my 1970 P6 3500S. The master 
cylinder appears to have a cover missing on the top where there's a spring 
exposed. What is this for and can I get a replacement cover.

Also, I'm under the impression that these master cylinders are the same as 
certain Jaguar ones. Is this true?

I would like to evaluate whether they are worth rebuilding or replacing if a 
Jag part is available.

Many thanks.

Al