1/4 steel tube penetrates the RS frame rail... ???

[rlaggren]

Directly beneath the cruise control on a bracket on the frame rail there is a 1/4" steel tube el the penetrates the rail - looks similar to brake line, but I doubt that's it. It runs across the firewall to the drivers side, drops down to the LS rail, does a U-turn and runs back up and across the firewall and heads down toward the rear end along w/the fuel lines. I'd say it's a fuel line w/a loop for cooling or something except I don't see where it connects to anything in engine bay - it just disappears into the frame rail.

Anybody know anything?

Rufus

[HowlerMonkey]

Might be a vent for the charcoal cannister.

[asavage]

Charcoal canister! AHAHAHAHA! That cracked me up, Thanks.

Yeah, it's a fuel tank vent line. Though the FSM calls it an "Expansion hose" and what they call the "Ventilation hose" runs to the top of the filler neck.

My '82 Wagon has the same. From the '82 FSM, page FE-6 (Wagons):
(click on image for larger)



If you click on that and look at the fuel lines ends, you'll see

• The tank's vent line goes to hose;
• To a short section of nitrile line;
• Fuel check valve (probably a liquid/gaseous check, so no liquid departs);
• Nitrile line;
• Steel line to the firewall (it ends short of the other two lines, where they go forward to the fuel filter area);
• Nitrile line again;
• Steel line to left frame rail, loop down, back to right rail area;
• Nitrile line;
• Steel line into right frame rail.

If you're brave or adventurous, you can pull that last steel line's clip and withdraw the line from the rail. My bet is that it just stubs open there, but maybe it goes a bit further.

If I had Nissan FAST loaded here (the 'doze box broke here, I may not fix it), I'd see what the hose diagram has to say about it.

[rlaggren]

Thanks, Al.

It's sure easier to look at an FSM page when I can blow it up 10x and actually see the little cross overs! <g> I may try and see what's on the end of that elbow, though I bet you're right - vent to atmosphere.

Something down there is making a CRACKING noise every once in a while for the past 8 months when I hit some minor road change. Tried jacking the car around, checking all the structure, sheet metal and suspension. Then last week I wiggled this elbow and CRACK! Maybe it's broke loose in there or something.

Cheers, Rufus

[asavage]

I took some pics today of the '81 Wagon in Mark's backyard. In the first pic, you can clearly see where the steel line from the tank end ends, and the connection to the steel line loop to the left frame rail area (right side of the pic) and back to the right frame rail.

The second pic shows the transition from the steel loop line to the right frame rail line that disappears.

(click on any image for larger)

[rlaggren]

That's the beggar. Good pics. I'll be fooling w/it soon - that noise is permanently on my list and it can't be _that_ hard to either fix or rule out the elbow.

Rufus