This article was updated Jan. 17, 2023. It was originally published Oct. 21, 2004. Using the correct thread is critical for proper mating and replacing hydraulic fittings.

A $1 hydraulic fitting can ruin a $10,000 valve or other expensive components in your ... This testing requires the identification of both mass per area and longest particle found in the system ...

Tube fittings are essential to hydraulic systems, connecting tubing and hose to pumps, ... ISO 6149 uses metric parallel threads and the male end includes a special identification groove.

Let’s clear up some misconceptions. Here’s what not to do when you find a hydraulic fitting leak and why. 1. Don’t use your hand to check for leaks.