Fuel Sending unit keeps weeping fuel

[timmycharger]

Any tips on getting a new fuel sending unit to seal properly? When I restored the car, I put in a brand new tank and re used my old sending unit.  Turns out I should have not used my 20 year old sending unit because it didn't work properly, always showed 1/8 tank no matter how much fuel I put in. 

I bought another one, don't remember the brand but aftermarket and installed it about a month ago. Good news is that the gauge now works, bad news is that it seeps out fuel. It doesn't drip but it will make the area below the sending unit wet after driving around.  I used the lock ring they provided with the rubber gasket and it leaked, I tried different combinations of using the old lock ring and gasket, then new lock ring with old gasket etc, all with same results.

I bought some permatex ultra rtv that is fuel friendly and was going to smear some on there but I am hesitant to do so. Any other tips to get this thing to seal? maybe bending the lock ring in spots so it presses harder on the gasket? I am using a rubber mallet and tape covered punch to knock the ring into place until it hits the little stops on all the sides , like I did the first time so I think I have it on correctly. 

Any tips or suggestions would be appreciated.   

[71charger_fan]

When I did mine, I used the lock ring that came with the sender and it did as yours is doing. Eventually, I bought an NOS lock ring. After installing the NOS lock ring, my leak stopped. The replacement lock ring I had just didn't clamp tightly enough.

[70sixpkrt]

Use you old lock ring. The new ones suck. I replaced my tank and sending unit last year and used my old lock ring and new gasket. Has not leaked.

[timmycharger]

Thanks for the feedback. I just picked up a NOS one on Ebay after I saw your response on another thread with the OP having similar issues I am having.