Hrs: 3

Fuel senders

Working on the fuel senders.

The manual says to drill the hole to 10 mm and add a countersink for the 0-ring on the outside.
However, on the original fuel sender the o-ring sits between the bracket and plate, which is more logical than on the outside.

With a step drill I enlarged the hole in the brackets to 10 mm and with a countersink drill I add the same size of countersink as on the original bracket:

Also the hole in the plate needed enlargement to 10 mm and a small countersink:

On the VAF forum I red issues with the fuel senders because there was no good ground connection. Just as Doug W. did I added a 4 mm hole, added a 120 degrees countersink and reused the ground lug of the original fuel sender plate with 4 x 10 mm rivet:

O-ring in the countersink of the bracket:

Reassembled the connector and added a bit Loctite 270 on each nut:

Testing the connection, resistance is between 10 and 190 Ohm and not short circuit:

Because of the orientation of the sender and the float the right tank will measure 190 Ohm with a full tank but the left will measure 190 Ohm with an empty tank. In the Garmin G3X manual is no information if the calibration will work with both situations.
Update 11-Feb-2019: Garmin support confirmed that this no problem when calibrating the fuel quantity.

The wire is too long, I though about shortening it but in the maintenance manual I red that TAF is not shortening it and is using a cable tie. The MIL spec cable ties from Panduit are resistant against hydrocarbons so that shouldn’t be an isse:

Temporary fit, ready to make the floats:

A couple of days ago I found out that the the breather line on the inside of the tank conflicts with the longer rivets I used for the fuel cap. I needed to remove that rivet and countersink that hole to use a sealed rivet 4 x 10 mm. I ordered a 90 degrees drill adapter to do this job: