The International Cessna 170 Association

The gauge sits in the middle seam of the tank but the outboard end of the tank is higher than the inboard gauge side so judging by looking at a tank, assuming your on level ground, you'd have to drain down to about 1/3 tank.

But why bother to be that precise. Open the fuel drain and let it run till it stops. This is well below the point of the fuel gauge in that tank.

Seafeye wrote:Only dumb questions are the ones not asked...

Here is mine. How low does the fuel in the tanks have to be to remove the gauge? So I don't create a volatile mess.

ALL of it needs to be drained! And the way to drain it is to, 1. Turn fuel sel OFF. 2. Disconnect fuel line going to the carburetor at the Carb. Use clean 5 gallon or (bigger if you want to carry them around) gas cans, Put the fuel line completely inside the can. 3. Bond everything together if you want to be extra safe. 4. Turn fuel selector on, to tank to be drained, Turn off if can gets full and replace it with another one; repeat till tank is empty. Dump the fuel back in when you are done.

Don't drain it from the wing drain.

I'm sure the internet experts will have better ways, but this has worked for me.

An alternate method if emptying a tank is to fly it dry using the skid ball, then switch tanks when the engine quits.

So Tim, why not drain it from the tank drain? That has worked well for me the last 4 or 5 times I've done it. And no matter how you do it it is most difficult to remove the unusable fuel so unless you remove the tank from the wings there will still be fuel in the system.

Bruce Fenstermacher wrote:So Tim, why not drain it from the tank drain? That has worked well for me the last 4 or 5 times I've done it. And no matter how you do it it is most difficult to remove the unusable fuel so unless you remove the tank from the wings there will still be fuel in the system.

Depends on how you do it. I can introduce you to a guy that burned his plane to the ground and almost lost an arm draining for the wing drain.

Ok Tim, fair enough. Draining fuel at any port without enough thought or benefit of the knowledge (experience) of others can be dangerous. I've spilled fuel all over me at both the fuel tank drain and the gascolator. It is not something I do willy nilly.

First I would highly suggest doing this work when the tank is already low and there isn't much fuel to drain.

Then no matter what port you use, insure you have enough container capacity to hold the fuel your draining. Think about how you are going to hold that container close enough to the port to capture the draining fuel. I've had fuel blowing all over the place with as little as a 4" gap between port and container. 5 gal containers full of fuel are heavy and often we are attempting to move then from an awkward position and we find we don't have the strength to do it. Finding out you can't hold 5 gal of gas straight out at arms length when the fuel is pouring out of the port is not a good time.

Figure out how your going to shut off the fuel if something goes wrong. The gascolator has an advantage here because if it is a stock setup the port flips open and stays open and it can be flipped closed any time. The wing tank drains need to be held open which is tedious at best and so most will remove them. This is always a recipe to be drenched with fuel. And reinserting the valve in a running stream of fuel to close it off is worse than removing it in the first place.

My preference would be to fly the plane till the fuel is low in the tank(s) to be worked on. Second would be to drain most of the fuel of the tank(s) from the gascolator if there is more than 5 gal remaining in the tank. At that point I will either hold the tank port open while the remaining few gallons drain into a container supported close under the wing or remove the valve carefully. I'll be ready with rags wrapped around my arm at my wrist to catch any fuel from running into my arm pit. And I will have a second container ready if the first fills up.

Of course fire protection and a friend willing to help should they be needed, is always welcome and smart.

Tim from this I.E. (When compared to most I'm not) Tim's method allows more control using the AC's fuel S/O valve. I think most of us have done it both ways though removing the wing drains to quickly drain and then applying anti-seize to the outer threads will make life easier when your tank sump drain seals eventually wear out. Caution should be exercised should dry cold air conditions exist.

Like I said, fly the tank empty and you wont have to figure what to do with the drained fuel or worry about fire or an explosion.

Arash,
Very carefully, and close to the airport.

Or, if you're kind of chicken, do one tank at a time.

The times I have had occasion to drain a tank, I had it as low as I could while flying on that tank, then pulled the sump valve to finish draining. However, Bruce's comment brings up a question. When the sump valve is removed, is there still some residual fuel in the tank? When I had occasion 4-5 years ago to remove my fuel tanks, I very carefully measured the volume of fuel that I could put back in both 21 gallon tanks. 19.6 gallons on one side (verified a second time) and either .1 gallon more or .1 gallon less on the other tank. (I do not remember there being any fuel left in the tanks after removing the sump valve, but its been long enough I can't be certain.) I am curious what volume others can get into their "empty" tanks. I suppose the size of the tail wheel might have a minimal effect. No doubt there is some capacity lost due to wing dihedral and between the filler and the front of the tanks due to the tail wheel stance. My tanks in my 172TD are identical to those in B model 170's.

Hi All,

I tried looking in the member section of the site for the templates and didn’t see it. Is it still available to members?

Thanks in advance!

Max

wyoflyboy wrote:Hi All,

I tried looking in the member section of the site for the templates and didn’t see it. Is it still available to members?

Thanks in advance!

Max

Found here: http://www.cessna170.org/forums/viewtop ... =41&t=9013

Thank you very much Bruce!