Quote Originally Posted by locodriver2007 View Post
Hi guys, can any one please explain the difference between the BIG Nut master cylinders and the standard master cylinder and why they were used? And did they come out standard on HJ Sandmans?
Cheers Mark
A "Big Nut" ([sic] - it is actually a bolt or a plug) master cylinder is a standard master cylinder. The are a cast iron master cylinder whose design incorporated the nut at the front so as to enable re-kitting. The common one that is seen nowadays is the replacement PBR (aluminium) type whose design does not require access to the front to re-kit (if you could or even wanted to it would be more cost effective to replace the whole master cylinder with a new one, they are now that cheap).

There are different numbers and different types of big nut master cylinders, HK-HG ones were a large, more oval shape to the resovoir, HQ-Z was a smaller, squared-off resovoir. My memory is fading (meaning don't take this as gospel) but remember seeing "DISC" on the odd nut here and there (A9X rings a bell....).

Hope that helps,

Dave.