centralcalvette

I replaced the fuel sender and gasket 4-5 years ago and now it's leaking pretty bad. I searched and didn't find any threads. Anyone have any hints on resealing it? I got a new rubber gasket from one of the big venders. Can I assume just clean both sides of the tank and the sender and hope for the best ?

62corvette

Many posts on this. Rubber reproduction o-ring and metal sealing ring are infamous for what you are experiencing. Did you soak the o-ring in oil overnight? That helps, especially if you have NOS GM parts.

centralcalvette

I haven't soaked it yet. this isn't a NOS product.

Tampa Jerry

As mentioned above, soak the O-ring in regular oil overnight. Make sure the O-ring is evenly spaced in the tank indent. Make sure the ring holding the O-ring in place is tight. I fill the fuel tank 5 gallons at a time and wait a few hours to make sure there are no leaks. Jerry

loup68

Why would you have to soak the O ring in oil? It is going to be immersed in gasoline in the fuel tank. Are they not using the correct O ring material for gasoline? Lou.

carriljc

Looks like you have a 69. I'm guessing it comes in from the bottom like my 68. My 68's has been wonderful over the years but a couple of years ago after working on my tank and removing and reinstalling it the dang thing started leaking. If you don't think it is the rubber o-ring, then it might be the metal part.
On mine it was actually the soldered metal part of the assembly.... I was surprised that it was soldered actually. Anyway, I cleaned it and removed the solder...then I BRAZED the the 2 parts together. Leak checked it over a couple of days by using paint thinner (no, not installed on the tank) over the newly brazed sections. Put it back in. Works like a dream.
By the way, I used a light coating of grease when installing the rubber o-ring.

centralcalvette

I replaced the seal last night after work. The old seal was destroyed! It feels like there's some sort of internal support that failed. The new one from the same supplier is fairly stiff both in bending and squeezing directions. The old one feels like spaghetti. I added 2 gallons of fuel and it held overnight. I appreciate all the input.

Hopper12

I wonder if the deterioration of the seal could have anything to do with corn gas? Asking for a friend.

carriljc

Doubt it. My seal is decades old and doesn't leak.

Tampa Jerry

The O-ring is immersed in motor oil according to the AIM. The oil lubricates the O-ring and offers some protection from the part of the O-ring that does come in contact with fuel. Jerry

loup68

My 68 AIM does not show anything about lubricating or soaking the gasket. I have never done this and I have changed a few GM gas tanks in my day. I can guarantee you that the original posters gasket got eaten up by ethanol. But I have a new gasket changed about nine years ago when I changed my fuel tank and it does not leak with ethanol fuel. Lou.

NHvette

I have a new repro fuel sender that I put in the car over 15 years ago.
For 15 years, it sat in the garage, zero miles.
Now, as I regroup to complete my journey, the fuel sender started leaking ... OUT OF THE ELECTRICAL TERMINAL !!
So, this weekend, I'm putting in a new Spectra sender unit, hope it lasts at least 15 years.

Good luck finding the cause of your leak and sealing. Hope it's just the rubber seal.