The International Cessna^® 170 Association

Could you just replace the floats with these new floats from Aircraft Spruce?
http://www.aircraftspruce.com/catalog/t ... kkey=17088

Kurt Aichele wrote:Could you just replace the floats with these new floats from Aircraft Spruce?
http://www.aircraftspruce.com/catalog/t ... kkey=17088

Yes, I believe some people have and the what I'd do if I wasn't so frugal. In reality I'd probably find a suitable piece of cork before I place the order from Spruce.

Corey, it appears that your rod is still too long to properly calibrate. Shorten it such that the float rests on the bottom of the tank at empty and can still rise fully without contacting the tank roof and it should work.

George, I haven't purchased the gauge (yet) and I am reluctant to at this point after reading the problems Jeff has had. I also am fully aware of the communication breakdown between the parties invloved on this subject. What I believe Jeff tried to explain and then I tried to clarify with my drawings is that the gauge manufacturer has changed the design in such a way that full range is now impossible. The gear section used to be 4" from the gauge. Now it appears to only be about 2" from the gauge. If the gear section only goes 2" into a 3-1/2" tube, then you can only bend the rod to either read correctly when empty or full, but not both. I tried to illustrate that in my drawings, the red lines representing the 3-1/2" long fuel tank tube. I have written to AS&S to verify my theory of the the shortened gear section and will reply to this thread if and when I get a reply from them.

10-22-15 Update: AS&S wrote back and said the gages in stock do measure 4" to the gear as shown on the drawing. I will order one today and post my installation results when done.

I have a potentially related problem. Since I bought the airplane a year ago, the left gauge only works about 10% of the time. When it does work, it works fine (bouncing back and forth like the right one in turbulence and fairly accurate). When it doesn't work, it pretty much stays stuck on full. This leads me to believe it's not a float problem, but I may be missing something. Thoughts?

DEM

For what it is worth:
I have had 2 issues with the original fuel gauges and both can be fixed.

1. The float fails and it can be replaced. I used cork and had to add several layers of (I think it was Spar Varnish). I would probably go with the Spruce float next time.

2. The magnet will slip on the rod and can cause intermittent readings. I used epoxy to glue it back on and it has held for years. I know of other also doing this.

I did buy 2 of the Spruce gauges and was never able to get them to work correctly as the geometry is wrong. Also the rod was very brittle and broke.

I found that just cutting them down worked accurately as I added 5 gal at a time.

Well my replacement gauge arrived and measured 4" from the face to the gear, just like the stock gauge and just like AS&S said it would. The gas tank neck measures 3-1/4". So I cut the rod to match the original float and DID NOT bend it as I did not see a reason to and staked both ends. The new gauge is now working and looks new like it should.

Side note: I replaced the gauge because my old one was stuck at 1/2 tank. When I removed the old gauge it seems to work flawlessly and I can not find any reason it would be stuck at 1/2. When I put the new one in and added fuel it was stuck on empty. I drained the fuel and removed the gauge and peered into the gas tank looking for clues. Seeing nothing I reinstalled the gauge and added 5 gallons of fuel. Still stuck on empty I removed the gauge again still baffled by it not working. As I was loosening the screws I did notice it start to work so I re-installed it carefully alternating screw sequence and rocking the plane each time to ensure it kept working. That did the trick. I can't explain it, either the float getting into a bind on the fuel bladder (this is a 180 by the way) or the dial getting in some weird torque position that stuck the needle. Maybe that's why you should bend the rod??

Thanks Corey,
I have to do this and was wondering what the deal was....Pete

Corey, Thanks for posting the pictures. (I've not fully understood why so many seem to have so much trouble with what seemed so simple to me. Mine work perfectly. Maybe because Bill Goebel did it for me.)

PS: He bent the rod exactly as the original in order to keep the 90-degree float position, but I see no reason your float shouldn't work just about as well. The synthetic float should also last much longer than only 60 years or so.

Clasic Aero has gauge support, floats, seals, complete assemblies. 480-650-0883