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Old vs New Vans resistive fuel,level sender

pjc

Well Known Member
I have an early slow build RV-6 with the “old” style SW level sensors (see pic).

The one from my left tank is no longer functioning properly and will have to be be replaced. Can I assume the “new” SW sender from vans (IE F-385B) is a drop-in replacement (mechanically and electrically compatible) ?

Anyone done this replacement/upgrade and have any advice? Any operational concerns with senders of different vintage in the two tanks?
(I am prepared for the Proseal mess to come — mostly just want to be sure the new sender will bolt up, the float will swing appropriately, and gauge readings will be approximately correct.)

Thanks
Peter
 

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Hard to see through the proseal, but looks like the screw mounting pattern might be different. You might have to fabricate an adapter plate if the center hole & screw holes don't line up, easy.
 
Hard to see through the proseal, but looks like the screw mounting pattern might be different. You might have to fabricate an adapter plate if the center hole & screw holes don't line up, easy.

Here’s the obverse view if it helps ....
 

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Fuel Tank sending units

I upgraded the tanks in my 4 several years ago that had the original SW units and the mounting holes matched up. The new ones come with a sketch and dimensions for bending and mounting the float on the wire arm which improved the accuracy of their fuel level readings.
 
I upgraded the tanks in my 4 several years ago that had the original SW units and the mounting holes matched up. The new ones come with a sketch and dimensions for bending and mounting the float on the wire arm which improved the accuracy of their fuel level readings.

Excellent, thanks.
 
pjc I agree with the prior post and have changed the senders in the RV6 I owned. I installed the latest version of the Stewart Warner resistance floats that Vans offered at that time. Everything matched up fine and I too recall instructions on bending the float arm either in the plans or with the floats.
Take your time sealing things and it will work fine. Good luck!
 
Follow up

New parts went in just as expected. I bent the new float rod to the drawing provided by Van’s. All sealed up and back in. Giving the flamemaster a couple days more to cure before testing with 100LL. Of note:

1). I will recalibrate as I refill the tank, but it looks like the new sender will effectively use 100% of on my Van’s gauge. (The old ones were calibrated, and marked, to show empty at about 40% gauge deflection).
2). I bought the 3.5oz Flamemaster kit from Vans. I was prepared with a scale and disposables to mix by hand, but the clever mixing tube apparatus made easy (and clean) work of mixing and dispensing the sealant.
3). 3.5 oz was far more than I needed. Surplus is in the freezer — will be interesting to see how long it lasts before curing.
4). With the float wire bent to the Vans drawing, and the deeper projection into the tank of the new style senders, I can no longer remove the sender while attached to the tank access plate through the wing root. The sender will have to be unbolted from the access plate (and my snazzy new sealant job broken open) to remove the sending unit or access plate. As I am still (happily) using the effective, but life limited, cork gaskets on the access plates, this will be a problem again in a couple of years.

In retrospect, knowing the above, I would have bought 2 new sending units and replaced both sides. Also, I would have bought the 3.5 oz (red) “access door” sealant formulation from flamemaster, and would have eliminated the cork gaskets (finally) in favor of sealant.

Peter
 
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