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Fuel and vent line grommets

FinnFlyer

Well Known Member
Van's specify (DWG 39) AN931 grommets. They require 3/4" and 1" holes.
Why not use SB-437 bushings?

Or, is it actually possible to install (push in over the skin) the grommets with the vent/fuel line inside the grommet, allowing the AN818 nuts to pass through the skin holes?

In other words, can you fabricate the line with grommets, nuts sleeves and flares on both ends and then feed nuts and line through hole in skin and then push the grommet in place in the skin?

Finn
 
Van's specify (DWG 39) AN931 grommets. They require 3/4" and 1" holes.
Why not use SB-437 bushings?

Or, is it actually possible to install (push in over the skin) the grommets with the vent/fuel line inside the grommet, allowing the AN818 nuts to pass through the skin holes?

In other words, can you fabricate the line with grommets, nuts sleeves and flares on both ends and then feed nuts and line through hole in skin and then push the grommet in place in the skin?

Finn

Never thought of fabricating the line with the grommet installed. Most just slice one side of the grommet and push it over the line.
The fittings will go through the holes allowing you to fabricate the line on the bench.
 
Plastic push-ins

I used the plastic grommets that came with the kit for internal line runs. Small hole, and they slip right over the vent lines. I installed mine with a dab of Proseal and they are there for life, and sealed from exhaust gas entry.
 
I used the plastic grommets that came with the kit for internal line runs. Small hole, and they slip right over the vent lines. I installed mine with a dab of Proseal and they are there for life, and sealed from exhaust gas entry.

Same here however the hole in the fuselage for the main fuel line is 1? so you can get the fittings through. The rubber grommet lends itself better at that location.
 
Grommets

Van's specify (DWG 39) AN931 grommets. They require 3/4" and 1" holes.
Why not use SB-437 bushings?

Or, is it actually possible to install (push in over the skin) the grommets with the vent/fuel line inside the grommet, allowing the AN818 nuts to pass through the skin holes?

In other words, can you fabricate the line with grommets, nuts sleeves and flares on both ends and then feed nuts and line through hole in skin and then push the grommet in place in the skin?

Finn
My lines are TS Flightlines but concept is the same.
I basically did. I drilled holes only big enough for fittings. Grommets were installed on the lines as they were snaked through holes then massaged into place in the hole. Not easy but holes are pretty well sealed. A dab of proseal will seal them completely.
 
My lines are TS Flightlines but concept is the same.
I basically did. I drilled holes only big enough for fittings. Grommets were installed on the lines as they were snaked through holes then massaged into place in the hole. Not easy but holes are pretty well sealed. A dab of proseal will seal them completely.

I have done this also, however, last time I just split the grommet. So much easier and you can not tell it was cut. Seems to be sealed well enough. No air leaks.
If you don?t split the grommet, a heat gun on a low setting helps soften it so you can massage it over the fittings a bit easier.

FYI. I pulled my hoses (older rubber with a Service life) and made hard lines. It is a right of passage to make these lines on a 6. Hose weighs more (a lot more, like a few ounces ;) ), May have a Service life, and, most importantly, its cheating.
 
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