Floats on fuel sending units.

G

Gary Brink

New member
It appears that I'm not completely done with my plane. Both floats on the fuel sending unit leak so I won't be flying it until I can get them replaced/repaired. They look good but looks are deceiving. Is there anything that I can use to coat them, dip them in, or replace them? Since they are approaching seventy years old, they can't be the first ones to fail.
And yes, I took them to a man who is a master welder and does a lot of soldering as well as teach it. His opinion is they are beyond repair in the traditional way.
 
Do the folks there at Alexandria A/C have them for the Cruisemaster? They are probably the same sending unit. Otherwise, if you can get the fuel out of them, maybe a thin epoxy coat???
BTW....Do not spend any more time ground running the engine or you risk a bad break-in!
If I were you, I'd go fly. You have one full tank....it's good for two hours+. Fly hard for 30 minutes, land and check every thing. If it's OK, go fly for one hour on the other full tank.
My opinion.....
Dan
 
I have done quite a bit of work with some epoxy but I don't know how it will get along with gasoline. Your advice on flying it hard is in agreement with the local A&Ps. Thanks for the advice! It is always welcome.
Gary
 
Gary, you can get new floats from Westach. I have their system in the crate. I damaged a float and a new one cost 5 bucks. Try them could be a cheap fix. Lynn :?:
 
Thanks, Lynn. I found a fuel tank sealer and have put several coats on the floats. It appears to be working but I will save this information from you in case there is a problem again. $5 per float would be a bargain!
Gary
 
Your floats must be Swiss cheese ! I have seen this in motorcycles, then they are truly shot.

But, a split or a hole alone does not make them "beyond repair". See article this year on the subject in
BC Contact. A light bulb with drive all the gasoline out of a float, and a dab of solder will seal it.

Even a LOT of solder will not keep the float from functioning properly. They have a LOT of buoyancy.
Bend the arm to compensate/calibrate - if your sender is otherwise ok.

Note that modern floats use a cylinder of closed cell foam, and dispense with the metal float.

3M makes Fuel Proof Coating.. ( used to seal tanks).. which would certainly seal your floats.
It is MilSpec, and doubtless ok for aviation.

you didn't hear it from me, but I would change out the whole shitaree.. the dumb 90 ohm guage, and the stupid
SW senders that don't match anything anywhere anymore. do this the day after your annual, and never look back.
there is modern SW automotive stuff that is off the shelf, bolt in, and looks identical, and better than the original.
nobody will ever care.
Meanwhile, make a calibrated dipstick, get a good timer, and keep notes. Trust them not some stinking guage.
 
The senders work fine but the floats were full of holes. I am confident they will work just fine now, but I agree to never trust the gauge. Know your fuel burn and time it. This has served me well for nearly forty years so I'm not apt to change now.
 
I would want to know the root cause of swiss cheese'd floats.

Gonna be electrolysis or rubbing.

If on the bottoms only... suspect the latter and I would personally want my float at least slightly above the bottom
at all times.

if all over... suspect electrolysis, and see what is cooking with the sender... and look at the tank
cause that is the other side of the circuit.

hmmm :shock:
 
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