Fuel System: fuel sender screws

[wuga]

1962 Lark wagon. Before I cause any damage, does anyone know what size the screw heads are to retain the fuel sending unit? I can't get any socket to fit properly, combination of rust and crud. The heads look sound enough, but just won't take a socket and I really don't want to drop the tank.
Thanks
Warren

[rockne10]

The screws are No. 10x5/8 and Studebaker #G145195
The special washer beneath them are Studebaker #187763

[bezhawk]

The head size is 5/16. An 8mm will fit just fine too. The washers originally were soft copper over asbestos. Plain copper will work fine too. I usually make sure they are dead soft by annealing them. Heat them red hot, and let them cool slowly, and they will be soft.

[StudeRich]

I have removed quite a few Original Fuel Sending Units, and have NEVER found one that did not have Standard, straight slotted Screwdriver type Screw Heads.

[bezhawk]

I guess you NEVER worked on an Avanti?

[wuga]

There are absolutely no slots in these screws. Thanks for the input.
Warren

[altair]

This tank is off a 63 lark and the screw heads are slots the heads may be 5/16 but they are round. An Avanti may be 5/16 but the PO is addressing a 62 Lark.

[wuga]

Well, I couldn't get the screws loose so I dropped the tank. Just as well, I am sending the rad out for boiling and pressure testing and I realized I had better send the tank as well. The same place refurbishes gas tanks as well as rads. After 58 years it was looking pretty kruddy and I am installing a new sender. Now, My apologies to Studrich, they were screws, but with phillip heads that were so filled with rust that there was no indication. I did loosen each of the five screws with a pair of vise grips and after I got one out, I started poking at it with an awl and found the indication of the X.
Thanks again guys
Warren

ps: the picture of that incredibly clean tank got me motivated to dig a little further

[StudeRich]

I guess you NEVER worked on an Avanti?

Of course not, the Car in question is a '62 Lark. My Avanti has no Fuel Sender issues, Yet!

[bezhawk]

When the original OP said he couldn't find a SOCKET to fit, that is why I assumed it was the hex type. silly me.

[wuga]

Sorry for the mis-information. I really couldn't see any screw slots and the heads were so rusty I wasn't sure that they weren't hex head. I'm glad I removed the tank. New engine and new carb, I don't want crap issues in the fuel line. I do appreciate all the help I have received here. I have been doing this for sixty years , but sometimes things just don't add up for me and I find it is better to ask.

Warren

[phwold]

On a past recommendation on this site I purchased a pack of ten Pressure-Sealing Washers direct from McMaster-Carr. Part # was 93781A011. They now come in packs of five for $9.68 They have Buna-N seals within the washer for a better seal, though I still needed to used a Permatex type sealer too.

[Badger]

I am struggling between competing problems..... 1) leaking screws, versus 2) poor grounding of the sending unit. The original crushable copper washers provided both solutions, a great method to seal the heads of the screws while providing conductivity for an electrical ground. But those asbestos filled copper washers are no longer available, so I am thrilled to find the recommendation by "phwold" for the products made by McMaster-Carr. I just ordered a few packages. Now I have my fingers crossed that my sending won't leak, and that the recently installed NOS sending unit will give me an accurate read (oh all right, a reasonable estimation). That would beat the heck out of carrying a spare gas can in the trunk.....

[RadioRoy]

You can put a connector/lug under a screw head and wire that to a good ground on the car's frame.