Quanta Gas Tank Leak (1968)

[William H.]

I installed a new Quanta gas tank about 8 years ago in my 1968 L-71 Corvette and have only used aviation fuel. The tank started leaking from around the perimeter of the sending unit. I changed the o-ring and snap ring and it is still leaking. It is not coming through the fuel sending unit and there is no staining where the o-ring is seated.

I think it may be coming through one of the spot welds where the snap ring retainer is attached. Has anyone heard of this happening? I pulled the tank but cannot see with my naked eye for sure. Thanks.

Bill

[Larry M.]

Re: Quanta Gas Tank Leak (1968)

Go back with GM NOS o-ring and retaining ring.

With tank out, I would partially (1/4 to 1/3 full ) fill it with water and do a very thorough leak check........or install the tank gas filler extension with non-vented cap, and soap test at 0.5 psig with air (hand pump). Attach pump thru tank sending unit outlet tubing connection.

If water is used, dry tank and sending unit thoroughly after, and spray sending unit down with some WD40 as well.

Larry

[Richard G.]

Re: Quanta Gas Tank Leak (1968)

I couldn't get a proper feel when I tightened my ring on my Quanta tank.
I could twist the sensor a few degrees with the locking ring tight.
The tank and sensor both came with their own locking rings.
After visually comparing the two rings I couldn't identify any real differences.
I swapped the import ring and the domestic locking ring anyway. The change imminently tightened up the sensor enough that I couldn't rotate it, by hand, any longer.
In my case it wasn't the tank but the imported fuel sender's locking ring that caused the issue.
Can you wiggle the level sensor with the ring tight?
I hate working with fuel running down my arms! I WAS GLAD I caught this before it caused a leak, which I am certain it would have.
I like Larry's idea of pressure checking the tank. Good idea on an frame off.
Any fuel leaks around our old cars makes me nervous.
Rick