I bought a sierra master cylinder at the Exeter kit car show last november and it is identical in every aspect to the one off my donor except for a 4th connection on the underside right at the front. I didn't notice this until I got home but decided to fit a bleed nipple to blank it off. Trouble is I just found out it is an M12 size hole and I cant find a bleed nipple big enough (M10 is the biggest I can find). Does anyone have an idea on how to blank this off and what it was intended for in the first place?
they were made different sizes to stop mongs on the line piping up wrong,can you use that hole and blank an m10?ill have a look in my box o bits and
see if i have 1
ny reason why there would be 4 connections, three the same size and one like a bucket? If the big one was plumbed into the back brakes for example
what are you supposed to do with the remaining 3? One to each front brake and a spare? It don't add up in my book.
You could allways plumb your inline brake light switch in the spare
Oh cheers for that Wendy. Two problems though.......
1) It's already fitted to the rear of the chassis
2) It doesn't have an M12 thread. Hold on a minute though I could wrap the threads in PTFE tape just a couple of rolls should do it.
Cheers Bob, you chocolate tea pot. 
paul,ive found a 12mm union but no 12mm bleed valves,you could block off a 10mm outlet with a nipple and use a 12 for the other,yours if you want it
quote:
paul,ive found a 12mm union but no 12mm bleed valves,you could block off a 10mm outlet with a nipple and use a 12 for the other,yours if you want it
so my idea would /could have worked then.
see you at stoneleigh