Friday, July 31, 2009

Hose Problems

Hose Problems

Yesterday a friend brought by some hoses off of his racing car for pressure testing. Normally, I only do aircraft hoses, but for a friend --OK

So the hoses fail. Look carefully at the hose to the left and you can see that the hose
pulled out of the socket. The hose was only engaged into the socket 1/4 inch or so. This is why he had a hose leak - it wasn't assembled properly to begin with.

Of all the different types of aircraft hoses I build, this style is the most tricky to assemble correctly. It is also the style of hose that race-car and custom car builders love to use. We use very little of this stuff on aircraft and in general don't like it - except it is "pretty" so I guess that is all that matters.

There are multiple ways you can get into trouble screwing the fittings onto this style hose. Here is just one tip:

After you screw the hose into the socket to the correct depth, place a "back-out" mark on the hose. Then when you screw the fitting together go back and make sure the hose hasn't pushed out of the socket as you screwed the nut-nipple Assembly into the socket.

Also, don't flood the cavity with oil as you can create a hydraulic lock that prevents the rubber from sliding into the recess.

Here is a link to another article on hose assembly at my web site:

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