Another, other fuel tank question!

[71newp]

Yeah, another one....
So I got a replacement (used) tank, and a NOS fuel sending unit from Van's. So I put in the gasket, the fsu and the lock ring. Once the lock ring is in place, the fsu is loose, it wobbles with hand pressure . Can I use a second gasket to take up the slack?
Thanks,
Tim

 

[bigmanjbmopar]

You sure you got the right parts? it shouldn't move at all once locked in.

 

[Yatzee]

Most likely the o-ring is the wrong cross section thickness ( possibly Chinese ) or the locking ring is the wrong fit. Try installing the fso again using the original 0-ring and collar once you clean and lube the original ring.

 

[Beekeeper]

The aftermarket lock rings are junk use the original lockring and no worries

 

[69a100]

I have seen this happen many a time! As said, make sure you have the right parts or use the old if not trashed out.
I have had to use 2 rubber gaskets in order to make it seal as they aren't as thick as originals. Use a thin film of gasket sealer and sandwich the 2 gaskets together and let cure then install, the lock ring will be hard to get started but when it's done it will be tightly sealed. Good Luck

 

[Gpuller]

I found that if you over tighten the lock ring the sender will be loose. There are some stops on the tank that the lock ring is supposed to lock into. Make sure lock ring isn't past the stops.

 

[71newp]

Thanks for all the replies!! It is a '75 gas tank with a NOS 75-76 fsu. The lock ring and gasket I tried came wrapped with the fsu, but they could be the(after-market/Chinese) problem. I will try to reuse the old lock ring if I can, but it is in REALLY bad shape, other wise the 2 gasket with gasket sealer will get a try!
Tim

 

[themechanic]

Use the zinc lock ring; it's the thicker one. You can buy them new with a gasket.

 

[71newp]

It's fixed! I had a "Spectra" lock ring and gasket from Rock Auto. I tried that and it was better, but still loose. So I used the RA gasket and the lock ring that came with the fsu and it worked perfectly. New question...
The Factory Shop Manual says to lube the filler neck. What the best/safe for fuel system lube. I'm thinking to try white lithium?
Tim

 

[Phil Anderson]

That's what I used.

 

[69a100]

Any type of slippery stuff will work, even plain liquid soap. Good Luck