replacing a fuel level float

[brian]

One of the tanks in my -6A does not read fuel level, or reads it sporadically. I got a new gauge, and that gauge seems to be reading zero, so I guess that leaves the float/sender.

Can a float/ sender go bad?

Will I be able to remove & replace the float/sender by removing the wing gap seal, or does the tank have to come off for access?

Are there any other things to look for that might cause the gauge to read sporadically or not at all?

thanks,
brian

[Jess Meyers]

Brian, yes the floats sometimes sink, we removed ours after grounding the plane and draining the tank, it was carefully removed from the wing root area. The float was replaced and re-installed, don't have the part number in front of me, but about $12.00

[Omega232Devils]

Brian,
I just replaced my sender on my left tank during a leak repair. I think it is feasible to remove just the sender through the access panel, although it depends on how it was put on. If put on with just the rubber gasket or a very thick layer of proseal, then it should be pretty easy for small arms to do it. (Definetly easier with the tank off!)
You may want to check the sender itself if you are using the Stewart Warner type float sender from Van's. The metalic strip that the float arm raises and lowers on to change the resistance (i.e. fuel levels) wears out pretty easily. For $27 bucks you can put a new one in.

Dan

[JonJay]

Here is a link to the process

http://www.vansairforce.com/communit...ht=fuel+sender

[Bob Redman]

G'day Brian,

I have just replaced the float on one of the SW senders provided by Van's.

I drained the tank. The float had detached and was lying at the bottom of the tank. I removed the sender unit (not the access panel) and could just see the float and wire lever lying on the bottom of the tank next to the first rib outboard. I used a small inspection mirror and flashlight.

I opened the bottom surface of the wing root fairing, then used the magnet on the end of the extendable inspection mirror to catch the wire lever, then manipulated the wire and float through the sender hole using my fingers.

I had not bent the wire sufficiently on the first 90 deg turn, so the wire did not stay in the two nylon clips in the sender unit. It had popped out after installation.

I tightened the radius of the 90 deg bend, fitted the wire to the sender unit, tested it using a multimeter, and refitted the now complete sender unit using Loctite #3 on a new 'rubber' ? gasket.

The repair has worked, and no leaks so far.

Regards,

Bob Redman

[Steve]

It sounds like an intermittent problem so verify all electrical connections are tight and corrosion-free before you R&R the sender.

[brian]

I checked the connections last night. They all seem good. I measured 44.2 ohms between the sender terminal at the tank and ground. It was 45.6 at the gauge end, so that seems reasonable. The reading did not change at all as I drained a couple gallons of fuel out of the tank.

So, I guess that leaves the sensor. It looks like an awful job to get at, and may be easier to remove the tank. For now, I'll probably continue to live with it and just use the fuel flow computer, which is quite accurate, but won't help me if I develop a tank leak in flight.

Does anyone know how many ohms there should be between sender terminal and ground when tank full and tank empty?

[Frank Smidler]

If it is an older 6 it may have hollow brass floats. Both of mine leaked and sank (at different times) requiring a change to the newer foam core floats. I removed the wing fairings and pulled out just the senders and not the access plate. If the floats are leaking you can tell by the weight and shaking them. When I replaced them I changed to machine screws (female hex) in place of the phillips screws, they were a lot easier to install using a 1/4" ratchet (idea from VAF, thanks).