But the idea is to get the ferulle to compress the tube against the insert to form the pressure sealing. Having a larger ID, or thinner wall provides some 'clearance' or a slight 'void' space between the liner wall and the insert. All things being equal, the ferulle will compress to a known dimension, so the ID of the ferulle will compress similarly. If the ID of the tube has been changed by drilling, so does the the amount the ID will compress against the insert.
It may still be enough to hold pressure for the brakes to work, but after continued pressure cycles it will eventually start to leak.
Be carefull. Mixing and making OR changing the specs will change the way things work.
Tom Swearengen, TS Flightlines LLC, AS Flightlines
Joint Venture with Aircraft Specialty
Teflon Hose Assemblies for Experimentals
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