For identification purposes, hydraulic tube fittings and connectors are separated ... pitch is the distance between threads (mm). A pitch gauge is useful for comparing threads.

Leaky hydraulic systems cost so much to maintain that many ... between certain kinds of threads are so slight that you should hold the fitting and thread-pitch gauge in front of a white background, ...

If some of the sealant gets into the hydraulic system ... reduced to 0.45 inches or smaller, the fitting should be replaced. For a quick check, a pin gauge works well.