Hi, i've got my brake master cylinders in place and i have a problem connecting the pipes to the fluid resevoir. The copper nut wont screw into the cylinder. I've tried another nut in the hole and it also goes 2 threads then gets stuck. Should i tap this and risk getting swarf in the cylinder or should i ask for a replacement?
Cheers
Adam

A little more info might help here. What make of m/c are you using?

IIRC the threads are tapered on Girling and Wilwood m/c (someone might correct me though ) so it might look as though they are cross threaded but are actually ok.

Girling (as with Lockheed, Teeves and Bendix ) brake systems do not use tapered threads.

However they can use either metric or unf threads depending on original application and year of manufacture.

Ah, I stand corrected - looks like a possible thread mismatch then.

I wouldn't force or tap anything, its your brakes...... Take the cylinder back and either get one which fits your unions, or unions to fit the cylinder.