Hey guys,

1. I've replaced most of the lines in my car with stainless braided lines with AN fittings. However, before I start putting gas/oil through them, I'd like to pressure test them to make sure they don't leak, and to make sure they'll hold together in at least a basic test. I have tried capping one end with an AN cap, putting a hose bard on the other end, and using a mitty vac to pull a vacuum. However, that will only tell me if the lines are airtight and I see two problems with this test. First, I'm assuming that they don't actually have to be airtight to be fuel/oil-tight. Second, it doesn't actually pressure test them to make the the ends won't just pop off once I apply normal fuel pressure to them. Sooo... Anyone have any good techniques for pressure testing lines, preferably doable in a normal garage? I'm not looking for anything crazy, just up to 100psi or so as a basic test. I'd also prefer to use liquid of some sort rather than just pumping them full of air. Of course if they're airtight, that's spectacular, but if they're not airtight, trying to pump them full of air doesn't help much.

2. Anyone have any good techniques for cleaning AN lines before installation to make sure there aren't any bits of stainless braid or dirt/dust in them? I thought about just blowing them out with my compressor, but I figured I'd ask and see if anyone has any better ideas.

Thanks!

- Andy

 

If they're not airtight they're not gonna be water tight!

Make some caps with tire valve stems on one end and a fitting for a pressure gauge on the other, pump them full of compressed air and see if it leaks out. On larger ones you should fill most of the way with water before applying the air pressure. That's a safety thing... if a large hose is full of compressed air there is a tremendous amount of stored energy in there and if it fails it will be impressive. If it's mostly full of un-compressible water and a small pocket of compressed air there is a lot less energy to release if it blows.

 

Good ideas on all counts. Got any suggestions on how to get the valve stem fitted onto a line? I can imagine how to connect a pressure gauge (NPT gauge -> NPT/AN adapter -> line) but I can't imagine how to connect a valve stem.

 

Drill a hole the right size in the cap and put a valve stem in the hole Use the metal type that uses rubber grommets and a nut.

Or just buy everything ready to go:

http://www.jegs.com/p/JEGS/JEGS-AN-H...87074/10002/-1

http://www.jegs.com/i/Earls/361/D016...oductId=763816

 

Here's what I ended up making for this. About $15 of home depot air compressor parts and the one AN fitting that I had laying around.

 

What about cleaning them? Im curious too.