Stripped Thread in Gas Tank

[Bob_Blue_BJ8]

Er, Uhmm, Guys:

Just got back from the local ACE Hardware. Took the old machine screw and the NOS sender unit to ensure fit of new screws and cap washers. Turns out the old screws are 8-32. The NOS sender unit holes are also 8's - 10-32 screw won't fit. Ended up buying 10-32 stainless screws as the next step up. No luck with cap washers that will fit at the corners of the upper sender unit body. I may just try expanding the holes in the original copper washers and making liberal use of Hylomar.

Bob the Bewildered

 

[dklawson]

the old screws are 8-32.

Well darn !!

The 10-32s you bought were the closest common larger size. It's time to add at least one tap to you soon to be growing collection.

 

[steveg]

This is good news. A stripped 8-32 is easy to deal with compared to a stripped 10-32.

 

[wangdango]

If you want 1st class hardware and a big variety of it, try McMaster Carr, do not have the website but you can google them. They have virtually any fastener anyone could ever want, which includes sealing washers, etc. My other suggestion is go onto Amazon and get a US/Metric nut/bolt "gauge," much like you see at hardware stores, while it does not do any of the British fasteners, it covers US/Metric and is just an all around good thing to have. Just my 2 cents!

 

[Bob_Blue_BJ8]

Guys, thanks again for all of the suggestions and advice. I wasn't able to deal with the darned thing until today. Figured I'd try different machine screws first to see if I could avoid tapping. The gas level is just an inch below the bowl and I didn't want to risk getting filings or chips down there. My first try without removing the sender was to use a 1/2" 8-32 in the stripped hole. It went in easy at first and then stopped well proud of seating. Cursing all things British and done by prior owners, I took the sender out. Gee!, there's a thick collar welded under the flange that must be made of sterner stuff than rest of the mild steel tank. Went to our ACE Hardware at picked up some 3/8" 6-32 and M4 .70 stainless screws with M4 washers that fit both. Turns out the tank likes the M4's. I dug out a new sender unit I had bought years ago figuring this was a good time to put it in with the new brass float I just got from Moss with a tube of Hylomar Blue (should be gold considering the price). Cleaned everything, set the new cork gasket in Hylomar, put the goop on top of the gasket, put the goop on all screw threads, tightened all down going to opposite sides like putting on a wheel. Then gooped around the edge of the sender unit flange. All seemed well. Finally put the key in the ignition and switched to accessory. Where before my gauge always read full until there was a cup left, it now reads empty with an almost full tank. Time to search other threads on sender units now.

 

[dklawson]

A couple of points....

Wipe the excess Hylomar off. It is not a sealer that should be applied thickly. You should put a thin film on both surfaces, let it dry until it skins, then put the surfaces together.

I don't know what year the transition happened with Healeys but during the mid 1960s BMC switched from the magnetic gauge system to the bimetallic gauges that use the voltage stabilizer. You cannot mix the gauges and senders from these two systems. The sender resistance changes in the opposite direction and the resistance ranges from empty to full are quite different.

You either need the correct sender for your gauge or you need a device like The Gauge Wizard from Spiyda Design in the U.K. that matches differing senders and gauges.

Link to Spiyda Design Gauge Wizard

 

[Bob_Blue_BJ8]

A couple of points....

Wipe the excess Hylomar off. It is not a sealer that should be applied thickly. You should put a thin film on both surfaces, let it dry until it skins, then put the surfaces together.

I don't know what year the transition happened with Healeys but during the mid 1960s BMC switched from the magnetic gauge system to the bimetallic gauges that use the voltage stabilizer. You cannot mix the gauges and senders from these two systems. The sender resistance changes in the opposite direction and the resistance ranges from empty to full are quite different.

You either need the correct sender for your gauge or you need a device like The Gauge Wizard from Spiyda Design in the U.K. that matches differing senders and gauges.

Link to Spiyda Design Gauge Wizard

Thanks, DK. Turns out that I drove the Healey the day before yesterday to coffee with my car group. The gauge stayed on "Empty" for the 12 mile trip there. On the way back, it suddenly popped up to "Full" and then happily danced around 3/4 on a tank for the whole trip back. Not too bad since my dipstick shows 9 gallons in a 13 gallon tank. I guess the float was initially stuck or the contact between the internal slider and coil needed wearing in (corrosion?). Whatever, it works now and I'm happily awating the next problem!