Having just installed my new Spectra Premium tank and sender (PN CR11F tank and a FG69B sender) a few days ago, I have a severe leak from my sender. The sender seems to fit loosely in the hole and I can move it around a bit even with the lock ring in place. I asked Spectra for advice and they recommended using Permatex fuel sealer, PN 85420.

I took my sender out and applied the sealer between the sender and gasket and tried to keep the gasket centered over the sender when I reinstalled it. It still leaks.

Any advice about fixing this leak?

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1965 Plymouth Barracuda,
225 engine, Quadrajet, HEI, Dutra Duals, 904 Torqueflite, 2.76:1 axle, Addco front bar
Rods & Relics - Fort Erie, ON / Collector Car Tech

Something's not made correctly. No sealing goop is called for at this junction!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I didn't think it was a good idea either. I thought the goop might be useful to keep the gasket centered on the sender while I install it though.

I thought the that looseness of the sender might be an clue as to the leak. I had a closer look at the sender's flange and it looked like the 2 locating tabs were bent inwards slightly. I bent them perpendicular (or a little past perpendicular) to the flange and reinstalled the sender just now. It seemed a bit let loose but I didn't want to risk uncentering my gasket with too much movement.

I'll try putting some gas in the tank in the morning and see it still leaks.

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1965 Plymouth Barracuda,
225 engine, Quadrajet, HEI, Dutra Duals, 904 Torqueflite, 2.76:1 axle, Addco front bar
Rods & Relics - Fort Erie, ON / Collector Car Tech

No, but there is gasket between sending unit and tank.

I had this happen to me on an aftermarket sender too. At first I thought the replacement gasket was thinner but that wasn't it. The locking ring that came with it was different then the original. It was a while ago so I don't remember the details exactly. The design of the bumps on the tab didn't allow for enough pressure to be applied to the sender so the rubber gasket wasn't compressed enough. I want to say I just re-used the original ring.

The looseness of the sender also made me suspect that the gasket wasn't being compressed enough. To increase the pressure, I tapped a bit on the 3 lock-ring tabs to bend them in a bit (with a brass rod to avoid sparks) but I don't think they moved very much.

I noticed that the Spectra lock ring is slightly different than my old OEM ring with a bump before each of the 3 tangs (for lack of a better description). I had been locating the lock ring's bumps on the centers of the tank's tabs but I thought that that the bumps were more of a means of preventing the lock ring from backing off.

I gave the lock ring a bit more of turn so that the tabs were centered between the tangs and the bumps. The sender definitely felt securely installed and did not leak when I refilled it.

The Permatex goo likely wasn't necessary but probably helped a bit to keep the gasket in place while I was tightening the lock ring.

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1965 Plymouth Barracuda,
225 engine, Quadrajet, HEI, Dutra Duals, 904 Torqueflite, 2.76:1 axle, Addco front bar
Rods & Relics - Fort Erie, ON / Collector Car Tech