Hi,

I had a 180 for years and anytime I parked it on a slope I always just selected the fuel selector to the upslope wing.

Fast forward and with my current 185 I parked for the first time with pretty full tanks on a slope. I did the same procedure and put the selector on the uphill wing.

Came back to it a couple days later and it was dripping fuel out the downhill wing anyways pretty bad. Lost a decent amount of fuel.

I see that 185s can sometimes have this happen with full tanks even with the selector in the “correct” position to prevent it.

Ideas? I see they make fuel pump vents plugs?

Fuel is probably transferring through the vent line that connects the two sides. It crosses above pilot's head just behind the windshield.

180Marty wrote:Fuel is probably transferring through the vent line that connects the two sides. It crosses above pilot's head just behind the windshield.

Copy that. Are there ways to prevent it other than adjusting parking spots? The spot I was in wasn’t really that “tippy”. My old 180 in the exact spot didn’t drop a drop.

I'm not familiar with the plumbing in a C-185, but my Maule has check valves in the cross-connect between wings that is supposed to prevent flow between wings when the right fuel selector position is chosen. One of my "check vales" was bad and I lost a fair amount of fuel due to siphoning when the tanks were full even on level surfaces. Once the siphoning started, it was really hard to stop. Replacing the errant check valve solved my problem.

180Marty wrote:Fuel is probably transferring through the vent line that connects the two sides. It crosses above pilot's head just behind the windshield.

This ^^^

MTV

Is there a way to stop that? My 180 parked in the same spot had zero issues. It isn’t even that uneven of a parking spot compared to places in Idaho.

My early C180 does not cross-feed with the selector in the "off" position.

Kinda just the design

guess you could put a small balloon catheter into the drain with a remove before flight on it

hotrod180 wrote:My early C180 does not cross-feed with the selector in the "off" position.

Oops, forgot that some if not all C185 fuel selectors don't have an OFF position.

Even the on/off has the same cross vent up top





At least per my 185 manual

That schematic is pretty useful. Note the check valves on each tank vent? Those valves have a tiny hole in them to allow air expansion in the tanks. If you park in the sun after topping those long range tanks all the way the fuel will begin to seep out those tiny holes. If you leave it long enough, especially on a hill, you can lose quite a bit of fuel.

I still like the snorkel vent out the top by the left wing root on my 1954 180. What I find interesting is you have to change to under wing when you replace the left bladder. But, 170's and 195's still can keep the out the top vent that doesn't have the leak problem. Why was the 180 discriminated against?

180Marty wrote:I still like the snorkel vent out the top by the left wing root on my 1954 180. What I find interesting is you have to change to under wing when you replace the left bladder. But, 170's and 195's still can keep the out the top vent that doesn't have the leak problem. Why was the 180 discriminated against?

Dunno about 'discrimination", but I don't like that AD requiring the change in venting.
1) underwing vents often tend to be problematic, as described on this thread.
2) the service kit to do the change is no longer available.
I'm dreading the day if/when I have to replace the LH bladder & comply with that moving the vent requirement.